Paving, Kerb & Retaining Wall
Handbook
Expect the Best
Disclaimer: Although the information in this book is presented in good faith and believed to be correct, Bosun makes no representations or warranties as to the completeness or accuracy of the information including variances in colour, size, texture and weight. Due to different aggregates used in various regions, variances will occur. Version 11, Printed June 2022
Expect the Best
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This book is best used in conjunction with our website: www.bosun.co.za
The pictures in this brochure, although not digitally enhanced, were nevertheless professionally taken from optimum angles to make for beautiful viewing. When these sites are seen in real life, they may appear less than picture-perfect due to the influences of outdoor conditions.
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Contents Paving Introduction Modern residential designs Modern commercial designs Sidewalks Roads Permeable paving
5-9 10-29 30-61 62-63 64-65 66-67
Paving Products Critical considerations when paving Colours and Finishes Products
69 70-71 72-99
Kerbs Dry cast kerbs versus wet cast kerbs Innovation Precast solutions Installation and specification Products
102-103 104-105 106-107 108-109 110-113
Retaining Wall Blocks Vertical fixed connection (VFC) wall block Robust block Versoblock Installation guidelines Design concepts
116-121 122-129 130-133 134-137 138-141
Information - Buying and Installing Paving Things you should know about paving prior to installation Paving material comparison Efflorescence Selecting the right contractor Laying patterns Installation guidelines Permeable paving design and installation guidelines Common paving installation problems Maintenance Guarantee Complementary Products Building Information Modelling (BIM) Product specifications
143 144-145 146-147 148-149 150-158 159-163 164-168 169 170-172 173 174-178 179 180
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Paving
Paving: Introduction
South African National Standard for concrete paving bricks explained The South African National standard for concrete paving blocks is SANS 1058: 2012. Bosun’s factories in Midrand, Brits and PE are amongst the first manufacturers of concrete paving blocks to be awarded the SANS 1058: 2012 mark. All our factories manufacture products according to the required specifications and product guarantees are based on them. Bosun kerbs and retaining wall blocks also comply with the South African National Standard as tested by the CMACS and other independent accreditation bodies.
What does it mean if paving blocks comply with the National Standard? • The manufacturer has an equipped laboratory and tests batches of manufactured blocks. • Blocks comply with strength specifications which are tested by means of tensile splitting. • Blocks comply with abrasive resistance specifications. TThis means that they are only permitted a specified amount of “damage” due to friction. • Blocks are permitted only minimal dimensional variances. • The visual quality of the blocks must be acceptable. A customer has recourse if necessary when it comes to the quality of paving blocks.
The fully equipped testing facility at Bosun Midrand. (All Bosun branches have fully equipped testing facilities.)
Bosun is a proud member of the Concrete Manufacturers Association, the American Interlocking Concrete Pavement Institute (ICPI) and the American National Concrete Masonry Association (NCMA). The principles of the design and installation of segmented paving, kerbs and retaining walls are greatly standardised across the world and the American associations did a sterling job in creating technical specifications, design manuals and training courses based on these principles. Bosun is committed to sharing the knowledge gained from these associations with our local market. In fact, much of the technical material purchased by Bosun is available to our customers through our website, free of charge. (www.bosun.co.za) Good infrastructure is expensive but it lasts a lifetime, is reliable, and allows society to develop on the back of it.
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Paving: Introduction State-of-the-art manufacturing equipment Bosun pavers are manufactured exclusively on Hess Machines and SR Schindler machines are used for beneficiated finishes. These companies form part of the “Top Werk” group, one of the world’s leading manufacturers of precast concrete equipment. The weak South African rand makes it more expensive to invest in this equipment, but we strongly believe that the accuracy of these machines, as well as their cutting-edge technology, result in products which are vastly superior to the average cheaper alternatives.
Transport A specialised fleet of trucks are contracted to Bosun. These vehicles are equipped with air suspension and aluminium decks to ensure a rigid, flat loading surface and the softest ride possible. In addition, all trucks are equipped with state-of-the-art cranes in order to offload quickly and efficiently, again minimising the risk of damage to products. Be aware that inferior delivery vehicles will cause damage to pavers in transit.
Expertise Owning the best manufacturing equipment is well and good. However, real value can only be added by the expertise of the people operating that equipment. Bosun has employed the expertise of Industry-leading European consultants and invested heavily in staff development and training both locally and with overseas partners. This has resulted in a product offering consistent with leading European manufacturers. Jochen Meyer, one of Bosun’s European associates and block making consultants.
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Larger paver sizes
Standard Brick
BOSUN Pavers
Many of our dry cast pavers are much larger than traditional South African paving bricks. Wet-cast concrete manufacturers have traditionally been known for the production of large “flagstones”, which are similar in size to Bosun’s large pavers. However, dry-cast slabs offer the following advantages over traditional wet-cast flagstones: • They are guaranteed to be dimensionally more accurate than wet-cast flagstones. • They have non-tapered edges for more accurate installation and smaller jointing gaps. • They have nibs for accurate installation.
Manufacturing technology Bosun manufactures a double-layer paver offering a “base” layer which reinforces structural integrity, while the “topping” layer provides a smooth, attractive finish which heightens abrasive resistance.
Guarantee Bosun offers a five-year guarantee on its products. (See the detailed guarantee on page173.)
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Paving: Introduction
Beneficiated Concrete Finishes Bosun offers concrete pavers with various beneficiated finishes or surface textures, which are new in South Africa and exclusive to Bosun. These finishes are achieved by means of technical processes with specialised machinery and equipment as shown below in these highly simplified graphic representations.
Ground pavers The grinding of concrete involves cutting the surface or “face” of the concrete with a series of diamond tipped blades, creating a fairly smooth texture. The smoothness of the surface texture is dependent on the use and application of the amount of cutting blades being used. The desired outcome of this process is to expose stones with interesting natural colours on the surface of the pavers. The difference between grinding, washed and shot-blast is that stones on the surface of ground pavers are perfectly flat and smooth whereas stones exposed by means of washing or shot-blasting will still have a naturally rounded shape. Grinding is an expensive process due to blade costs.
Shot-blast pavers The shot-blasting process involves peppering pavers or kerbs with “shot” or small beads of steel which are fired at high velocity by means of compressed air. The shot actually dents the surface of the product bit by bit, thereby dislodging small particles of concrete which then fall away. This exposes small stones and other aggregates on the surface. In a sense, the result is similar to that of washed pavers, as described opposite, but a shot-blast texture is slightly smoother, although more irregular than a washed texture.
Ground and shot-blast pavers These pavers are ground and then lightly shot-blasted in order to provide a rougher surface texture.
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Washed or exposed aggregate pavers In the washing process fine cement particles are removed from the paver’s surface with a special water-spraying technique which exposes beautiful small stones in various colour schemes, creating interesting and hard-wearing surface textures.
Chamfered pavers Chamfering is a process where an angled edge is cut on the paver. This could be done on any or all of the edges.
Calibrated pavers Calibration is a process whereby the bottom of a paver is cut with a diamond-tipped blade in order to create a thickness which is dimensionally accurate and consistent. It is almost impossible to manufacture large pavers and maintain accurate and consistent heights. The SANS height variance specification on large pavers is ±5mm. This could result in a 10mm variance between two adjacent pavers, though one which is still within the specified range. All large paving stones should be calibrated prior to resale.
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Paving: Modern Residential Designs
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Paving: Modern Residential Designs
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Grass or other groundcover is used as an integral part of this permeable paving system. By planting groundcover in the holes designed in these pavers, a green surface is created. Grass will not be damaged by cars driving or parking on these pavers. Reality check It is more expensive and requires more skill to install permeable paving.
Paving tip The best paving will fail if it is installed incorrectly. Select your installer very carefully and remember that while it is more expensive to install paving properly and correctly, it will pay off in the long run. (Please see page 148.)
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Paving: Modern Residential Designs
Paving tip Large pavers are more difficult and more expensive to install. When using large pavers on driveways, special care should be taken during the earth preparation.
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Reality check Concrete paving’s colour will fade over time. Dust engrained into capillaries could also dull the paving. The colour of the paving will appear to be more vibrant after rainfall.
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Paving: Modern Residential Designs Bosun XXL Urban pavers can be used as stepping stones. Their 900mm width allows enough space to walk on comfortably.
Paving tip Paving blocks are heavy, making them difficult to transport and handle. Always bear in mind the cost of delivery when purchasing paving.
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Black Smooth Ethnic Pavers installed in a herringbone pattern. A herringbone provides superior interlock as it can withstand traffic in multiple directions Urban Medium pavers in a natural looking Basalt finish. Refer to page 86 for more information.
Paving tip Exercise caution when using cement grouting, as it could permanently stain your paving and might also crack or break up in the future. The best and proven fixed grouting material is polymer grouting such as Romex, which is available from Bosun.
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Paving: Modern Residential Designs
Urban Large Pavers in Granite, installed in a herringbone laying pattern. Urban Large Pavers in Granite, installed in a stretcher bond laying pattern.
Paving tip Installation of paving will most probably cost more than what was originally anticipated. However, if paving is to last for a lifetime, it is wiser to spend more and avoid taking shortcuts.
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Bosun’s Urban Medium Pavers in a Basalt finish used as cost-effective garden edging. Such applications are more aesthetically please than standard bricks and garden kerbs. Reality check Paving blocks take some time to settle on a site before they look their best. Allow about six months for colours to settle. Efflorescence is also most likely to appear within the first year of installation. Venetian pavers in black colour used to edge a driveway paved with SmartStone cobble pavers.
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Paving: Modern Residential Designs
Paving tip Bosun pavers can be sealed with a polyurethane or a water-based acrylic sealant. This will enhance the colour and protect the paved surface. Beware of sealing pavers prior to the appearance of efflorescence, as this will trap the efflorescence within them. Also ensure that the pavers are thoroughly cleaned so that you do not seal in the dirt. Pavers need to be 100% dry before sealing. Lastly, be cautious when sealing driveways, as warm tyre residue could bond with the sealant, causing unsightly marks.
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Reality check It requires more skill to install intricate designs. Always consider the thickness of pavers when using a variety of pavers in conjunction with each other. If one paver is thicker or thinner than the others, the procedure becomes complicated.
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Paving: Modern Residential Designs
The Urban range of pavers is available in various sizes which could be used to install in combination with each other. (The pavers on this page were sealed with a water-based sealant.)
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Reality check Combination patterns are more difficult to install, requiring more skill and therefore customers can expect to pay more for this type of installation.
Combination of different Urban Pavers in a Marble colour
Paving tip The use of a large plate compactor is recommended for the levelling of combination patterns. Small compactors will bed smaller pavers deeper than larger ones.
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Paving: Modern Residential Designs Traditionally, concrete paving bricks or “cement bricks” have satisfied the price-conscious segment of the market. Many paving contractors would deliver a sales pitch such as: “Clay bricks will cost you x amount. If you’re looking for something a little classier, simulated stone or ‘SmartStone’ is an option, but it’s more expensive. However, the cheapest option we can offer you is cement bricks.” This has changed in the past five years. Modern manufacturing equipment and increased technical proficiency have enabled concrete paving manufacturers to produce unique products and remarkable finishes at the upper end of the scale.
Paving tip Never install plastic sheeting under paving, as it badly affects the base structure. Plastic sheeting DOES NOT prevent weeds from growing. Weeds grow when seeds are deposited from above into the joints between pavers.
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Paving tip Structural integrity of a paving installation comes from good compaction of layer works beneath the paving, not from the paving blocks themselves. When using base material found on site, it must be excavated and compacted in layers using a heavy roller.
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Paving: Modern Residential Designs
XXL Pavers by Bosun Bosun XXL pavers are 27 times larger than standard bevel pavers. This type of paving is new to South Africa and because of their size, they require special equipment and skills to install. Every paver’s size is 900mm x 600mm and the blocks weigh more than 90kg each.
Paving tip Pavers are fragile and should be handled with care. They should never be thrown or tipped out of wheelbarrows.
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Paving tip What happens underneath your paving is more important than the visible paving. Consult our installation section at the back of this book for necessary questions to ask your installer. (See page 148.)
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Paving: Modern Residential Designs
Paving tip It is likely that your pavers will be affected by efflorescence in their lifetime. This is a temporary natural white film that appears on concrete, clay or natural stone, but eventually disappears on its own. (See page 146 for a comprehensive explanation of efflorescence.)
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Reality check Tyres leave marks on any type or colour of paving. Darker colours will disguise the marks more effectively, though they will still be visible.
Modern residential pathway created with Bosun XXL Paving Slabs in Marble colour.
Smooth Ethnic pavers in Brown
Paving tip When your paving is jointed with sand, top up your joints by sweeping dry plaster sand over the paving from time to time. Always sweep diagonally across the paving.
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Paving: Modern Commercial Designs
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paving: Modern introduction Paving: Commercial Designs
Sandton Gate
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Design by Boogertman & Partners
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Paving: Modern Commercial Designs
St. Alban’s College
Paving tip Bosun recommends that an engineer design the layer works of any commercial paving project.
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Design by Boogertman & Partners
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Paving: Modern Commercial Designs
Ellipse Waterfall
Design by Green Inc Landscape Architects
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A combination of Linneo pavers in Granite, Ebony and Ivory were used to create striking contrasts.
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Paving: Modern Commercial Designs
Nedbank Menlyn Main
Design by Interdesign Landscape Architects
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Talk to Bosun about special paving elements like tactile pavers, walkway demarcations and concrete bollards.
Reality check Your project is likely to be affected by efflorescence in its lifetime. Expect this and make the investor aware of it. It is a temporary phenomenon in concrete, clay and natural stone and will eventually disappear. (See page 146 for a comprehensive explanation of efflorescence.)
Paving tip Be careful when using power washers to clean paving, as this could blast the jointing sand out of the paving joints.
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Paving: Modern Commercial Designs
Time Square – Menlyn Maine
Paving tips Bosun has various textures and colours available in order to create flow and demarcation in landscaping designs. Avoid grouting pavers with red plaster sand, as it will stain your paving. Paving on steep slopes is more complex than level areas. Use edge restraints and pay special attention to layer works on such installations.
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Design by Interdesign Landscape Architects
Reality check Combination patterns are more difficult to install, requiring more skill and therefore customers can expect to pay more for this type of installation.
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Paving: Modern Commercial Designs
Menlyn Podium
Design by Uys and White Landscape Architects
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Paving tip Bosun’s sister company, SmartStone, produces wet-cast pavers, cobbles and flagstones with contrasting textures to Bosun pavers. These can easily be incorporated into Bosun’s paving designs.
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Paving: Modern Commercial Designs
Alice Lane Phase 3
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Design by Ochre Office Landscape Architects
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Paving: Modern Commercial Designs
Mall of Africa
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Designed by Daniel Rebel Landscape Architects
Reality check Discolouration of concrete can be seen on bridges, road barriers, kerbs and paving. There are various causes, but natural colour variations are a characteristic of concrete as a building material. Don’t expect paving which is exposed to and installed in the African elements to look like ceramic tiles. It definitely won’t!
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Paving: Modern Commercial Designs
Cell C
Paving tip SmartStone, Bosun’s sister company has various copings and bollards which could be used in conjunction with Bosun pavers. Paving is porous. Before site completion, there is a big risk that paving might be stained by the red soil found in many areas in Gauteng. Contractors transferring it with their feet and rainstorms are usually the main culprits. It is therefore ideal to install paving as late as possible in a project’s development, although this is not always practicable.
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Design by Insite Landscape Architects
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Paving: Modern Commercial Designs
Nelson Mandela Square
Design by Bentel and Associates
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Paving tip Bosun offers various unique surface textures in order to achieve your desired effect. At Nelson Mandela Square, the architect envisaged the use of pavers with an aged appearance. In order to create this appearance, these pavers underwent a grinding process where specially selected aggregates were exposed in the surface texture. After this process, the pavers underwent a light shotblast where they were peppered with small steel balls in order to roughen the surface and further enhance the texture.
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Paving: Modern Commercial Designs
Oxglen Office Park
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Design by DDV Design Group
Paving tip Pavers should be levelled with a plate compactor or, in the case of large pavers, with a large rubber mallet. However, a plate compactor should always be used when “shaking” jointing sand into joints.
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Paving: Modern Commercial Designs
Trumpet on Keyes
Designed by StudioMAS Architecture and Urban Design
Paving tip Installing paving on a concrete slab, eg above underground parking, is very specialised. Always consult an engineer for such designs.
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Reality check Concrete is porous. Fine dust might settle in its capillaries and paving will appear dull. Regular washing of pavers might be required in order to restore its vibrance.
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Paving: Modern Commercial Designs
Summit Place
Design by Uys and White Landscape Architects
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SmartStone cobbles were used to good effect in this project to demarcate parking areas.
Paving tip Bosun recommends the use of interlocking shaped pavers in areas with heavy vehicular traffic.
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Paving: Modern Commercial Designs
BMW Head Office
Reality check XXL Urban pavers are extremely heavy and therefore very difficult to install. Please talk to your Bosun representative about special tools we have available to simplify the installation of these large pavers.
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Design by African Environmental Design
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Paving: Modern Commercial Designs
Newtown Junction
Design by Daniel Rebel Landscape Architects
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Lifestyle Garden Centre
Paving tip Natural surface textures are created by means of specially selected aggregates. The pavers used in this project underwent shot-blasting that exposed small stones which, in the process, created a slip-resistant, yet unique external floor.
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Paving: Sidewalks
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Sidewalks in Tshwane
Sidewalks in Waterfall City
Sidewalks in Vilakazi Street Soweto
Bosun pavers are also widely used for sidewalks within private developments.
Red sidewalks in Soweto In 2006, in commemoration of the 30th anniversary of the 16 June 1976 student uprising in Soweto, the route from Morris Isaacson High School to the Hector Pieterson Memorial was paved with red pavers. This was the first stage of a broader project to pave all the routes students took on their way to Orlando West, where a violent confrontation with the police took place. Red pavers were initially chosen to symbolise the bloody sacrifice made by the students on this day and in the days immediately after it. Over the years, this project evolved and is currently also linked to the beautifying and greening of Soweto. Many of the routes in commemoration of 16 June have been completed, while the red sidewalks have almost become a Soweto trademark. The plan is to eventually have paved sidewalks throughout Soweto that will serve its community more effectively. Sidewalk in Sandton CBD
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Paving: Roads
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Numerous municipal, provincial and even national roads (including tollgates) have been paved with Bosun Interlocking Pavers. Segmented block paving is popular for use on roads because: • Segmented block paving is not susceptible to potholes. • Installing it creates local jobs for communities. • It creates a sense of ownership for local communities. Municipalities where Bosun paving has been used in the recent past: • Johannesburg • Madibeng • Tshwane • Moses Kotane • Ekurhuleni • Govern Mbeki • Lesedi • Dr Moroka • Emfuleni • Chris Hani • Nelson Mandela Bay • Phumelela • Cacadu • Mangaung • Nkonkobe • Rustenburg
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Paving: Permeable Paving Permeable paving is a paved surface through which water is able to pass between the blocks. The benefits of a permeable paving system are: It assists stormwater drainage systems, natural breakdown of pollutants and water harvesting, while preventing soil erosion. The Bosun Waterwise Paver™ has four different installation techniques allowing for optional levels of permeability. With the correct design, water could either infiltrate the subgrade (ground), or be channelled to an underground storage facility, which has proved to be an extremely effective means of water harvesting.
Reality check It is far more expensive and requires much more skill to install permeable paving.
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These pictures were taken at the same time on a rainy day. This site is installed with Bosun Waterwise Pavers and normal interlockers. It can be seen that water has drained through the permeable paving in the parking area, whereas the water has dammed up on the standard interlocking paving. This site has a system of underground pipes and an underground catchment tank in which rainwater is harvested for irrigation.
Reality check A permeable paving system requires an engineer’s design and very specific layer works to function correctly.
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Paving Products
Paving Products: Considerations
Critical considerations when paving: Installation, installation, installation: Use a reputable installer. The vast majority of site complaints we attend to relate to bad workmanship and inadequate earth preparation by installers. Refer to the “Selecting the right contractor” section on page 148 of this handbook prior to seeing an installer. Beware of scam artists who disappear with deposits or do not provide detailed quotations or invoices. Also beware of installers who do not keep you informed on a regular (preferably daily) basis of their progress on the work. Check references and consult consumer bodies and public tools like Hellopeter.com. Contractor memberships with industry bodies like the Master Builders’ Association or Concrete Manufacturers’ Association provide you with some form of recourse when complications arise. There are reasons that some products and services are cheaper than others: We know this, yet we all push the boundaries in order to save money. The best advice in this regard is to be informed beforehand as to what can be expected. Have reasonable expectations: Most people expect to pay less for paving than the amount they eventually do. Remember, paving is expected to last a lifetime and in many instances, it could also carry vehicles (like a normal road). In South Africa paved areas are usually large, as we have bigger yards and outside living spaces. We always recommend saving a little longer for good-quality work, rather than opting for something cheaper. Paving is made to be rugged and is installed outdoors, so do not expect it to look as smooth and glossy as ceramic tiling. Moreover, when paving is newly laid, it does not yet look its best. It needs a few months to “settle down”. There are some practical considerations when it comes to buying paving: In general, paving trucks are big and bulky. Ensure that they can gain access to residential estates and boomed-off areas. Paving is usually offloaded by cranes in bundled packs. However, it then needs to be moved manually to the place of installation. For this reason, you need to be very clear about where it should be placed. Allow for breakages and cutting when ordering paving: 5-10% extra should be sufficient. Preferably be present when paving is offloaded and inspect the packs, or at least do this before unpacking and installation take place. Once packs are broken, there is always the possibility of the installers and manufacturers blaming each other. Is the installation of paving quick and easy? The simple answer is “no”. It doesn’t matter what an installer tells you: expect inconvenience. Most paving can’t be installed on top of existing paved materials. There will be digging, refuse and dust. Still, no matter how disagreeable this is to cope with, never try to rush the installation. Rather let the installers do the job properly. Remember, you expect paving to last a lifetime, so one or two days of additional inconvenience are nothing in the bigger scheme of things. It is also essential to take the recommended period of “curing” seriously and not using a driveway or patio immediately after paving. Starting to use a driveway too soon will negatively impact the integrity of the installation. Are some suppliers better than others? Not all paving bricks or stones are the same. Our aim in stating this is not to try to win your business, but simply to make you aware that there are unscrupulous paving manufacturers out there and that what you think is the cheapest option could well turn out to be the most expensive one in the long term if the work is done incorrectly. What paving material is the best? Make a wise decision when it comes to the type of paving material you select. Refer to our paving comparison for an unbiased guide to the most common paving materials used in South Africa. Again, this guide is not a selling tool. All paving materials have both advantages and disadvantages.
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Paving Products: Colours and Finishes
Colours and Finishes Many of Bosun’s colours and finishes are new and have never been seen before in South Africa. The following colours and finishes are available on 50mm - 80mm pavers.
Shades of Grey
Grey
Granite
Ash
Natural Stone Texture Fade Resistant
Shades of Brown
Tan
Brown
Sahara Shades of White
Marble
Kalahari
Natural Stone Texture Fade Resistant
Ivory
Natural Stone Texture Fade Resistant
Shades of Red
Red
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Multiblend
Autumn Blend
Shades of Black
Black
Basalt
Natural Stone Texture Fade Resistant
Ebony
Natural Stone Texture Fade Resistant
Stone Finishes
Stone Black
Stone Grey
Stone White
Chestnut
Please refer to page 83 for our Flagstone Exclusive Finishes Please note: Our blended colours vary from paver to paver, creating a random organic effect. We recommend viewing a number of sample pavers together in order to perceive the holistic picture of any one colour. (Feel free to visit our factories where we will assist you in this regard.) Due to photographic and printing processes the colours in this catalogue may not be a hundred percent accurate. Concrete is made from natural products which are mined and crushed and the resulting aggregates are never exactly the same colour. These differences do reflect in the final products in the form of slight colour variations. It is therefore recommend to mix pavers from different packs when doing an installation.
Scan to view on our website
Not all products are available in the colours listed on this page. Please consult your Bosun representative for more information
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Paving Products - Regular Paving
Bevel Bond Paver A traditional brick-shaped paver with bevelled edges. This product is 50mm thick and is the most cost-effective paving solution for residential driveways and walkways.
Dimensions Height Mass per Paver SANS Pavers per m2
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200mm x 100mm 50mm ± 2.15kg 1058: 2012 Approved 50
Split Bevel Bond Paver A smooth surfaced paver with bevelled edges, which creates the impression of 100mm x 100mm cobbles when installed.
Dimensions Height Mass per Paver SANS Pavers per m2
200mm x100mm 50mm ± 2.15kg 1058: 2012 Approved 50
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Paving Products - Regular Paving
Rio Rocoso Bevel The Rio Rocoso Bevel has the appearance of a ripple surfaced cobble with bevelled edges.
Dimensions Height Mass per Paver SANS Pavers per m2
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200mm x 100mm 50mm ± 2.15kg 1058: 2012 Approved 50
Paving Products - Designer Paving
Bosun Cobble This paver creates the impression of 150mm x 150mm cobbles when installed. It is manufactured in a double paver shape in order to create better interlocking when installed, compared with smaller square cobbles.
Dimensions Height Mass per Paver SANS Pavers per m2
300mm x150mm Gauteng: 60mm PE branch: 55mm ± 5.8kg 1058: 2012 Approved 22.2
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Paving Products - Designer Paving
Venetian Paver This paver is slimmer and longer than a traditional paving brick in order to create a totally unique design.
Dimensions Height Mass per Paver SANS Pavers per m2
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255mm x 55mm 60mm ± 1.90kg 1058: 2012 Approved 72.7
Smooth Ethnic Paver This bevelled paver is slightly larger than a standard paving brick.
Dimensions Height Mass per Paver SANS Pavers per m2
200mm x 150mm 55mm ± 3.7kg 1058: 2012 Approved 33
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Paving Products - Designer Paving
Urban Paver Exclusively available from Bosun, the Urban paving range is available in various sizes, with the Large, Slimline and XXL Urban pavers being much larger in size than standard paving bricks. Urban’s feature a mini-bevelled edge in order to create a smooth, seamless look. The modular design of these modern pavers allows for the different sizes to be installed in combination with each other.
Standard Brick
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Urban range
Small Dimensions Height Mass per Paver SANS Pavers per m2
200mm x 100mm 60mm ± 2.6kg 1058: 2012 Approved 50
Medium Dimensions Height Mass per Paver SANS Pavers per m2
200mm x 150mm 60mm ± 3.7kg 1058: 2012 Approved 33.33
*Available in the following exclusive finishes:
Marble
Granite
Ebony
Ivory
Ash
Stone White
Stone Black
Stone Grey
Not available in Stone Finishes or Chestnut*
Slimline Dimensions Height Mass per Paver SANS Pavers per m2
400mm x 200mm 60mm ± 11kg 541 13
Large Dimensions Height Mass per Paver SANS Pavers per m2
400mm x 300mm 60mm ± 17.5kg 541 8.33
Chestnut
XXL Dimensions Height Mass per Paver SANS Pavers per m2
900mm x 600mm 80mm ± 95kg 541 1.85
Granite
Marble
*Please consult your Bosun representative for more information
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Paving Products - Designer Paving
Linneo Paver These large, rectangular pavers are available in two sizes and create a seamless, modern feel. Install them in combination with each other or singularly. A linear, staggered stretcher bond pattern is recommended.
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Standard Brick
Linneo Range
Large
Small Dimensions Height Mass per Paver SANS
300mm x 120mm 80mm ± 6.5kg 1058 : 2012
Paver per m2
27.77
Dimensions Height Mass per Paver SANS Pavers per m2
600mm x 240mm 80mm ± 23kg 541 6.94
Exclusive Finishes* Marble
Granite
Ash
Ebony
Ivory
Also available in Stone Finishes - see page 71
*Please consult your Bosun representative for more information
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Paving Products - Designer Paving
Bosun Flagstones Bosun Flagstones are specially designed for use on patios, pool surrounds, home aprons, commercial walkways and piazzas. They are thicker than tiles in order to withstand the elements, but thinner and visually more attractive than traditional paving products. These Flagstones have straight edges that allow for less obtrusive jointing gaps. Their dense surface allows for effortless cleaning and prevents unwanted liquid penetration, that could permanently stain your outdoor floor.
Rectangular Dimensions 200mm x 400mm Height 35mm Mass per paver ±7.06kg SANS N/A Pavers per m² 12.5 Square Dimensions 400mm x 400mm Height 35mm Mass per paver 12kg SANS N/A Pavers per m² 6.25
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Flagstone Exclusive Finishes Smooth Finishes
Flagstone Black
Flagstone White
Flagstone Tan
Textured Finishes
Flagstone Shotblast Black
Flagstone Shotblast White
Flagstone Shotblast Tan
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Paving Products - Coping
Cosmopolitan Coping A large, flat-face contemporary coping. It features a natural concrete textured finish and is distinctive from the Bullnose coping. Best used with larger Bosun elements.
Dimensions Height Mass per Paver Pavers per Linear meter
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588mm x 288mm 50mm ±155kg 1.67
Bosun Bullnose Coping This coping is designed for use on the edges of patios, pools, steps and staircases. Therefore, to ensure a slip-free surface, it is manufactured with a shot-blast texture.
Dimensions Height Mass per Paver SANS Pavers per m²
300mm x 100mm 55mm ±3.6kg 1058: 2012 Approved 10
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paving: introduction Paving Products - Premium Finishes
Organic Finishes Bosun’s organic finishes are new to selected designer and interlocking pavers. The colour and texture on these pavers are derived from natural stone aggregates exposed by an advanced “washing” technique. Stone doesn’t fade, neither will these pavers. The end result is a natural looking, fade resistant, coarse exposed aggregate finish. Kalahari and Basalt finishes are available on our Urban Small & Medium and both 60mm and 80mm Interlockers. These finishes are exclusively available from our Midrand branch.
Basalt
Kalahari
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Bosun Colourfast Finishes - The Pavers That Won’t Fade Bosun Colourfast finishes are predominantly derived from the specially selected, natural stone aggregates used in their topping. As the name suggests, the colour of these pavers will not fade - as natural stone does not fade. Due to their superior colour fastness, these finishes lend themselves to the design and creation of permanent colour contrasts on a paved surface. Colourfast finishes are suitable for both residential and commercial applications. Colourfast finishes are available on selected Urban, Linneo, and both 60mm and 80mm Interlocking Pavers. These finishes are exclusively available from our Midrand branch.
Ebony
Ivory
Ash
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Paving Products - Premium Finishes paving: introduction
Stone Finishes The specially selected aggregates used in these pavers are exposed by “grinding” the surface to eventually cut through the aggregates. The grinding process creates a smooth exposed aggregate finish with the most interesting effects, especially when viewed from close. This unique grinding process is commonly referred to as a “honed concrete finish” or a “polished concrete finish”. Not one of these pavers are identical and the contrasting colours in them creates life in the paved surface. Selected Urban and Linneo pavers are available in these polished finishes.
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Stone Black
Stone White
Stone Grey
Chestnut
Exclusively available from our Midrand branch
Paving Products - Interlocking Paving
60mm Interlocking Paver An interlocking paving brick, ideal for commercial applications. Interlocking pavers are robust, providing hard-wearing durability and a multitude of other benefits.
Dimensions Height Mass per Paver SANS Pavers per m2
200mm x 100mm 60mm ± 2.6kg 1058: 2012 Approved 50
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Paving Products - Interlocking Paving
80mm Interlocking Paver This is an interlocking paving brick for industrial or heavy commercial applications where trucks, forklifts and other heavy machinery are prevalent. This paver has also been used extensively on municipal roads.
Dimensions Height Mass per Paver SANS Pavers per m2
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200mm x 100mm 80mm ± 3.5kg 1058: 2012 Approved 50
Shale Interlocking Paver This paver has a wavy-surfaced stone texture. It is available with or without bevelled edges and appears more natural and rustic with wear.
Dimensions Height Mass per Paver SANS Pavers per m²
200mm x 100mm 60mm ± 2.6kg 1058: 2012 Approved 50
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Paving Products - Interlocking Paving
Rio Rocoso Interlocking Paver Designed to “lock” together when installed, this paver has the appearance of a ripple-surfaced cobble with bevelled edges. It combines the functionality of interlockers with the aesthetic appeal of a cobble.
Dimensions Height Mass per Paver SANS Pavers per m2
92
200mm x 100mm 60mm + 2.6kg 1058: 2012 Approved 50
Citylock Paver An interlocking paver that resembles smaller and larger pavers installed in a pattern using two differently sized pavers.
Dimensions Height Mass per Paver SANS Pavers per m²
230mm x 140/90mm 60mm/80mm ±3.5kg 1058: 2012 Approved 39
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paving: introduction Paving Products - Permeable Paving
Waterwise Heavy The Waterwise Heavy merges permeability with superior structural performance. The block features a specially designed double nib system which provides superior structural performance and adequate spacing between the pavers to allow water to drain through the jointing gaps. Furthermore, they ensure enough space between the pavers to accommodate the correct jointing material for permeable pavements as specified by the Interlocking Concrete Paver Institute (ICPI). At 80mm thick and with specially designed nibs, the Waterwise Heavy permeable paver is suitable for residential, commercial and industrial applications. The simplistic rectangular shape creates a functional and aesthetically pleasing paved surface.
Dimensions Height Mass per Paver SANS Paver per m2
200mm x 100mm x 80mm 80mm ±3.87kg 1058 50 units Learn more on page 164
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Waterwise Paver Bosun has pioneered the innovative, registered-design Waterwise paving system. Designed for permeable paving systems, this paver anchors itself to adjoining pavers, leaving gaps between the joining areas through which water is able to drain. The Bosun Waterwise Paver™ could be used in four different installation options, determined by the level of permeability required because of its unique registered design. With the correct design, water could either infiltrate the subgrade (ground), or be channelled to an underground storage facility, which has proved to be an extremely effective means of water harvesting.
Dimensions Height Mass per Paver SANS Pavers per m2
239mm x 209mm 60mm ±4.35kg 1058: 2012 Approved Varies according to permeability (ref pg146.)
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Paving Products - Permeable Paving
Waterwise Citylock An interlocking paver that resembles smaller and larger pavers installed in a pattern. This paver is similar in appearance to the Bosun Citylock paver, but offers permeability and can be used in conjunction with the original Citylock paver, as illustrated below.
Dimensions Height Mass per Paver SANS Paver per m2
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230mm x 140/90mm 60mm ±3.5kg 1058:2012 39
Grass Blocks The Bosun Grass Block is a permeable paver designed to facilitate the growth of grass in paved areas. The design of the grass block encourages water to drain through the voids where vegetation grows while offering sufficient structural integrity to allow for vehicular traffic. Our grass blocks are often used for erosion control purposes.
Dimensions Height Mass per Unit SANS Pavers per m2
600mm x 400mm 100mm ± 35kg N/A 4.2
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Paving Products - Permeable Paving paving: introduction
Bosun Buffalo Block Suitable for traditional grass block installations as well as permeable paving systems, the highly versatile Buffalo Block creates an interlocking matrix of individual blocks positioned together to establish an erosion-resistant surface while remaining flexible and fit for vehicular traffic.
Dimensions Height Mass per Unit SANS Pavers per m2
98
400mm x 216mm 100mm 12.227kg N/A 13.55
The unique geometry and patented nib design provide the necessary curvature and interlock required for small water channels and v-drains. Furthermore, less surface preparation is required on uneven surfaces, due to the tapered nib design. The Buffalo Block is ideal for roadside drainage channels, as the vegetation growth within the voids of the block can create the appearance of an aesthetically pleasing ‘soft’ road shoulder. Unlike traditional grass blocks, the Buffalo Block’s compact design results in less on-site wastage and breakage, ease of installation and a higher load bearing capacity.
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100
Kerbs
Kerbs
101
Kerbs: Dry Cast Versus Wet Cast In Europe 95% of kerbs are manufactured using the dry-cast method. In South Africa, as far as we are aware, Bosun is the only manufacturer of dry-cast kerbs.
dry cast wet cast
Wet-cast kerb (left) installed next to a dry-cast kerb (right).
wet cast
dry cast
Two years later. Dry-cast kerbs are darker. The surface doesn’t abrade as easily and better withstands acid attack in the long term.
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dry cast Dry-cast kerbs are manufactured in the same way as interlocking pavers.
dry cast
wet cast Wet-cast kerbs are manufactured in the same way as cobbles.
wet cast
Bosun dry-cast kerbs were used on the left-hand side of this traffic island. Wet-cast kerbs were used on the right-hand side. It is clear to see that the dry-cast kerbs are dimensionally more accurate than the wet-cast ones.
Reality check Kerbs are installed on roads. Expect them to discolour quickly due to tyre marks, exhaust fumes and asphalt. The production capacity of dry-cast kerbs is not limited by availability of moulds.
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Kerbs: Innovation
Castle Bottom Kerb A
B
C
D
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Conventional Kerb
Castle Bottom Kerb An innovation in kerbs is the Bosun Castle Bottom Kerb, currently available in our 1 000mm Figure 3, Figure 7 and Figure 8C kerb. (Please see page 110, 111 and 112.) The Castle Bottom Kerb has ribs or cavities across the bottom of its surface. Advantages of Castle Bottom Kerbs, compared with conventional kerbs: • The cavities provide a grip for installers when laying the kerbs, which allows for much easier handling. (Left Row A ) • The cavities make the Castle Bottom Kerb much quicker and easier to install. Where unlevelled screed surfaces force installers to uplift, fill up and re-lay conventional kerbs, it is easier to manoeuvre a Castle Bottom Kerb into place, with the screed being displaced into the cavities in the kerb. (Left Rows B & C ) • Kerbs are laid on a concrete screed. Because the Castle Bottom has more point loads, it will sink into the screed, providing much better adhesion in all directions. The Castle Bottom eliminates air pockets in the screed beneath the kerb. Air pockets could create tensile weaknesses beneath the kerb when installed. (Left Row D ). Patent: ZA 2012\09544
Kerbs with nibs Bosun’s Figures 3 and 7 kerbs are available with nibs. Please see page 110.) Advantages of Kerbs with nibs compared with conventional kerbs: • The nibs ensure easier installation with the correct spacing between kerbs. • This reduces the likelihood of air pockets in the grout. • Because the nibs touch the adjacent kerb, greater force stability is achieved, resulting in less movement when installed.
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Kerbs: Precast Solutions p
Problem
s
Solution
Bosun Channel Kerb
p
Formworks with cast in-situ channels.
s
Bosun precast channel kerb.
s
Bosun precast edge beam with interlocking nib.
Interlocking Edge Beam
p
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Cast in-situ edge beams.
p
Problem
s
Solution
Transition Kerb
p
Cast in-situ transitions to mountable kerbs.
s
Bosun precast transition kerb.
s
Bosun delineator kerb.
Delineator Kerb
p
Back-to-back kerbs to create bus lanes.
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Kerbs: Installation and Specification
The installation of kerbs is specified by SANS 1200MK. In principle, the following is prescribed: •
Trenches on which kerbs are to be installed should be excavated and well compacted. If the engineer finds that the in-situ subsoil is not good, an imported sub-base material should be used.
•
A bedding material of at least 50mm thickness should be used that consists of crushed stone, cement and sand, with a maximum particle size of 13,2mm.
•
There should be close joints no larger than 10mm between kerbs and they should be filled with 3:1 sand/cement. The joints must be pointed. Ends of kerbs should be well moistened before jointing and filled joints must be covered and kept moist for 48 hours. When joints have cured, an appropriate sealant must be used, where necessary.
•
Allow for expansion joints of at least 12mm at intervals of at least 20m.
•
After jointing, the kerbs must be backed with concrete “haunching” of at least 15Mpa and the space behind kerbs must be back-filled and well compacted in layers.
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SANS specifications for concrete kerbs explained The South African National Standard for precast concrete kerbs, edgings and channels SANS 927:2013: •
Bosun kerbs all adhere and are manufactured to SANS specifications. Product guarantees are based on the same rules.
•
Kerbs are made up of high-quality materials.
•
The kerbs must be free of cracks, other than hairline cracks. They must also be free of visible twists and dents.
•
Kerbs dimensions must remain within ±3mm in length and straightness.
•
Kerbs must comply with strength specifications.
•
Kerbs must be sampled and tested in a lab. Reality check Don’t expect kerbs to look like the smooth, shuttered concrete seen on buildings. Dry-cast kerbs might initially appear to be darker than wet-cast ones. In the construction of roadways, kerbs will take a beating from heavy machinery used in layer works. Contractors should be aware that kerbs are not unbreakable.
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Kerbs: Products
Figure 3: Barrier Kerb A half-battered, heavy-duty barrier kerb used to create traffic islands and corners. It restricts access to the pavement and is used in heavy-traffic areas.
Fig 3 Long
Fig 3 Short
Length
1000mm
330mm
Mass Per Unit
±110kg
±36kg
SANS
927 : 2007
Figure 4: Barrier Kerb A half-battered, medium-duty kerb installed in townhouse complexes and small shopping centres. It restricts vehicular access to pavements.
Fig 4 Long
Fig 4 Short
Length
1000mm
330mm
Mass Per Unit
±80kg
±26kg
SANS
927 : 2007
Figure 7: Semi-mountable Kerb The Figure 7 semi-mountable kerb is used on public roads and other applications where limited access to a pavement is required.
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Fig 7 Long
Fig 7 Short
Length
1000mm
330mm
Mass Per Unit
±105kg
±35kg
SANS
927 : 2007
Transition Kerb (7/8C) This kerb serves as a neat and simple transition between the Figure 7 and Figure 8C kerbs. It is easy to install and does not require on-site curing.
Length
1000mm
Mass Per Unit
±120kg
Figure 8B: Medium-duty Mountable Kerb A medium-duty mountable kerb, ideal for use in residential estates and residential driveways on ramps.
Fig 8B Long
Fig 8B Short
Length
1000mm
330mm
Mass Per Unit
± 86kg
±27kg
SANS
927 : 2007
Figure 8C: Heavy-duty Mountable Kerb A heavy-duty mountable kerb for use on commercial and municipal road edgings where vehicular traffic needs access.
Fig 8C Long
Fig 8C Short
1000mm
330mm
Mass Per Unit
± 107kg
±36kg
SANS
927 : 2007
Length
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Kerbs: Products
Alternative for Figure 10 Kerb A kerb that can be used as an alternative to the Figure 10 kerb.
Length
1000mm
Mass Per Unit
±73kg
Figure 12: Garden Kerb Garden kerbs are ideal for neat and efficient edging of any paving. Well-installed garden kerbs keep paving in tact and ensure that it doesn’t move. It can be used on residential and light-duty commercial applications.
Length
500mm
Mass Per Unit
±12kg
SANS
927 : 2007
Figure 14: Kerb Only available in Port Elizabeth. It serves as a channel for run-off water and is used on commercial and industrial roads.
Length
112
1000mm
Mass (1000mm length only)
±60kg
SANS
927 : 2007
Edge Beam Commonly installed on paved areas with steep slopes in order to prevent horizontal creep and the subsequent opening of paving joints.
Length
1000mm
Width
150mm
Height
150mm
Mass Per Unit
±55kg
Channel Kerb Channel kerbs are used as a method of preventing the degradation of road surfaces and edging between channels and the kerb. Used as an edge restraint, they carry the flow of water to the nearest catch pit.
Length
1000mm
Mass Per Unit
±60kg
Delineator Kerb: Double-sided Semi-mountable Kerb This kerb allows for buses to mount the kerb if necessary while smaller vehicles cannot. It is a cost effective alternative to placing two separate figure 7 kerbs back to back. Applications include bus lanes and BRT’s, shopping malls and parking bays. The Delineator kerbing system includes spacing blocks that allows for drainage. Length
1000mm
Mass Per Unit
±115kg
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Retaining Walls
Retaining Walls
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Retaining walls: VFC Retaining Wall System
Bosun VFC Retaining Wall System A retaining wall block awarded with three patents.
The VFC (Vertical Fixed Connection) retaining wall system is designed to construct 90° concrete block retaining walls. In addition, the VFC system meets SANRAL’s requirements for vertical retaining walls outlined in South Africa COTO specification for roads 2019. The system uses a positive mechanical interlock connection between the geogrid and the block through an oval shaped interlocking pin. In addition to the fixed connection, the VFC uses a double nib system, resulting in increased shear resistance than what a single nib system can offer. The innovativeness of this system is evident in the fact that the company holds two direct patents and one indirect patent on various aspects of its design.
A positive mechanical connector and double nib system: • • • • • •
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The VFC block features a specially shaped channel that enables the connection of geogrid to a custom-designed concrete pin (locking mechanism). The system mechanically secures geogrid to the block, enabling the building of vertical, 90 degree retaining walls. Patent: ZA 2018/04934 Vertical walls are required on various infrastructure projects with space constraints. The VFC creates more usable ground space. The VFC further boasts a double nib system, resulting in increased shear resistance than what a single nib system could offer. The VFC block is compliant with SANS8006-1 and tests have been conducted in accordance with ASTM D6638 and ASTM D6916 to verify the local facing stability. The VFC block has been designed for use with a variety of both imported and locally manufactured geotextiles available in South Africa.
Retaining walls: VFC Retaining Wall System Easy to use and install: As with the patented Bosun Castle Bottom kerbs (Patent ZA: 2012\09544), the VFC Base Block has cavities on its bottom surface. These cavities make the base block much quicker and easier to install. Where an imperfect bedding layer forced installers to uplift, fill up and re-lay conventional blocks it is easier to manoeuvre the Castellated block into place, with the bedding layer/levelling pad material being displaced into the cavities in the base block. • •
• • •
•
The castellated base block simplifies bedding and sets the levels for all succeeding layers. The base block comes with a simple jig which enables the placement of a spirit level across both axes. This, in turn, facilitates accuracy and ease of setting out. The base block can be inverted and used as capping on the top of the wall. The locking of the geogrid into the VFC block is quick and simple. The weight of the standard VFC block is approximately 24kg, making it light enough for one man to handle, in turn promoting hand labour. The VFC block complies with SANS 508 and block heights in particular, are guaranteed to be consistent.
VFC block Dimensions Height Mass per Block
300mm x 300mm 140mm ±26kg
VFC base block Dimensions Height Mass per Block
300mm x 250mm 80mm 13kg
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Retaining walls: VFC Retaining Wall System Positive mechanical connection (locking mechanism):
Locking mechanism
Design concept
Design concept:
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Retaining walls: VFC Retaining Wall System Interchangeable face: The VFC features an interchangeable face. This means that it can be used to construct linear, concave and convex wall geometries with a 2m radius. No concrete infill or cutting of blocks is required when constructing curves. The larger block face is used by default, while concave curves can be achieved by simply flipping the VFC block over from front to back (Patent: ZA 2017/08449). Convex curves can be achieved by shifting the rear parts of the blocks towards each other. This will result in less cutting on site.
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Retaining walls: VFC Retaining Wall System Practical advantages: Roads built on the VFC system are better equipped to handle potential impacts on barriers. Conventional retaining wall systems using friction principles may fail as opposed to the fixed connection system used with the VFC.
VFC System
Conventional System
Due to the fixed connection and strong nibs, zero relative displacement occurs between blocks experiencing building surcharge.
VFC System
120
Conventional System
Retaining walls: VFC Retaining Wall System
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Retaining walls: Robust Block
Robust Block The Robust Retaining Wall Block, developed and manufactured by Bosun, is an innovation in the retaining wall market. The block features new patented design elements with better weight distribution and height tolerances compared to standard retaining wall blocks. The specially designed nib also offers excellent shear resistance. The Robust Block is a cost-effective solution for large, engineered solutions. The Robust Block can be used in either a closed or open face formation, with the open face being extremely popular due to the economic advantage of using less blocks and saving on costs. At 5.1 blocks/m² using an open formation, it is one of the most competitive in the market. An open face formation can be transformed into a closed face by using a cost-effective slider between the blocks. The slider prevents soil erosion between the blocks and most importantly on the top row – regardless of formation.
Robust block Dimensions Height Mass per Block
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440mm x 300mm 250mm ±47kg
Bosun Robust Block advantages 100% Consistent Block Heights A critical aspect with retaining wall blocks is consistency in block heights. SANS 508, (the official South African specification for retaining wall blocks) specifies dimensional differences of not more than ±3mm. The Bosun Robust Block guarantees these height tolerances or your money back. If there are any dimensional inaccuracies, it is at the back of the block that can’t be seen and it doesn’t have any structural influence.
Why are blocks of consistent heights important? • The layer on top of irregular blocks will rock back and forth. • There will be uneven weight distribution of blocks placed on top of an uneven layer, leading to stress points and, ultimately, block failure. • Geotextiles placed between uneven rows of blocks might tear or rip out. • It wastes a lot of time to level blocks on site with little stones, etc. (Patent: ZA 2016/00519)
Special V-shaped stiffeners The Bosun Robust Block has a superior crushing strength compared to most standard concrete retaining blocks. The crushing strength is derived from various design elements, including the unique V-shape stiffeners in the block. Because of the Bosun Robust Block’s superior crushing strength, the construction of retaining walls which are 10m high is possible it. The V-shaped stiffeners also offers a better distribution of force and, in combination with the flat top of the block, offers better resistance to deflection on the sides and top of the block.
Flat surface Because this block has a flat surface, vertical pressure from above is displaced more evenly and point loads are more widely spread than with conventional retaining blocks.
Nib The Bosun Robust Block offers excellent horizontal shear (sliding from the back) resistance because of its specially designed nib.
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Retaining walls: Robust Block Other advantages of the nib are: • Fewer blocks are used in closed laying method. • Gaps between the blocks are smaller in the open laying method. • There is less chance of soil falling through gaps in the open installation method. • It is possible to build steep walls at angles of up to 80°.
0pen blocks Soil erodes into the block at the back (open side) of the Robust Block. This means that soil doesn’t leave the retaining structure when it erodes.
Installation guides The Robust Block offers installation guides on the top part of the block. These lines will ensure consistent overlapping of blocks on site.
Handling The blocks is easy to pick up and handle on site. It is possible to carry six blocks with a gravity clamp.
Slider for closed face installations The use of the slider allows for a more cost-effective closed face option which prevents soil erosion between the blocks and most importantly on the top row, regardless of formation. In addition, the slider can improve the aesthetics of the wall as it promotes plant growth within the retained soil. Dimensions Height Mass
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320mm x 60mm 230mm ±9kg
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Retaining walls: Robust Block
Block usage in a closed face laying pattern 9,09 Blocks/m² Block usage for open face laying pattern 5,13 Blocks/m²
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Retaining walls: Robust Block
Robust Block When the wall is packed using the nib, an 80° angle is naturally created.
There are two ways to create less steep walls: 1
Block layers could be moved back. Loft required in degrees
2
Place upper block (x) mm back (layer by layer)
60°
144,3mm
65°
116,6mm
70°
91,0mm
75°
67,0mm
The foundation could be tilted in order not to lose the benefits of the nib.
Tilt measurement = foundation width (x) x tan O Degree of wall required
O
400
75°
5
35mm
400
70°
10
70,5mm
500
75°
5
43,7mm
500
70°
10
88mm
600
75°
5
52mm
600
70°
10
105,7mm
Foundation width (x)
128
Lower back of foundation by
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Retaining walls: Versoblock
Versoblock With its registered design, the Versoblock offers superb versatility. The lip helps to ensure that the blocks above keep their position behind the blocks below. • Versoblocks could be used with either the front, back or side exposed, to create different finishes. • Versoblocks could be installed closed, creating a solid retaining feature – or open in order to create a living wall of plant life. • The load is carried on five points on the block, compared with three points on similar systems, thereby increasing the stability of the wall. • Versoblocks are available with a lip which simplifies installation and increases stability.
Dimensions Height Mass per Unit
420mm x 300mm 200mm ± 28kg
Profile without lip Unit of measurement: mm
The load is carried on five points on the block, compared with three points on similar systems. This increases the stability of the retaining wall.
Profile with lip
The lip helps to ensure that the blocks above keep their position behind the blocks below.
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Installation options Versatile in aesthetic appeal, Versoblocks can be used with either the front, back or side of the block exposed to create different finishes. Side on Closed Face
Front on Closed Face
Back on Closed Face
Versatile in strength, Versoblocks can be installed in numerous ways to cater to the retaining wall’s strength requirements.
Side on open
Front on open
Back on open
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Retaining walls: Versoblock
132
Reality check
The strength of a wall comes from the design – not the blocks. It is therefore critical to consult an engineer when a wall is higher than 1,2m.
133
Retaining walls: Installation Guidelines Important aspects of retaining walls The strength of a wall comes from the design – not the blocks. It is therefore critical to consult an engineer when a wall is higher than 1,2m. Bear in mind that a retaining wall must resist the lateral pressures generated by the soils behind it – or, in some cases, water pressure too. Every retaining wall supports a “wedge” of soil. As the setback of the wall increases, the size of the sliding “wedge” is reduced. This reduction lowers the pressure on the retaining wall. The most important consideration in proper design and installation of retaining walls is to recognise and counteract the tendency of the retained soil to move downslope due to gravity. This creates lateral earth pressure behind the wall, which depends on the angle of internal friction and the cohesive strength of the retained material. Lateral earth pressures are zero at the top of the wall and - in homogenous soil - increase proportionally to a maximum value at the lowest depth. Earth pressures will push the wall forward or overturn it, if not properly designed. Also, any groundwater behind the wall that is not dissipated by a drainage system causes further hydrostatic pressure on the wall. It is critical to have proper drainage behind the wall in order to limit the pressure on the wall’s design. Drainage materials will reduce or eliminate the hydrostatic pressure and improve the stability of the material behind the wall. When the weight of blocks alone is not enough to resist soil loads (walls higher than 1m), horizontal layers of geotextiles are used to reinforce soil behind walls. With proper soil reinforcement and design, retaining walls can be constructed to heights in excess of 20m. Why retaining walls fail: • Insufficient drainage. • Incorrect or non-use of Geotextiles. • Insufficient compaction of soil behind the wall. • Inadequate foundations.
Critical considerations • The NHBRC stipulation is that a wall of up to 1,2m does not need an engineer’s approval if the soil is good and compactable, with no excessive stormwater and there is no load pressure on the wall, such as vehicular traffic or buildings. Retaining walls which are higher than 1,2m need an engineer’s approval. • You cannot build a retaining wall where clay and non-compactable sand conditions exist. • For a wall which is higher than 3m, the common rule is to use Geotextile in every third layer (we recommend that with a Bosun Robust Block, a Geotextile be used in every second layer). • Consider available space, drainage and water management.
Foundation All retaining walls should have a foundation, even if the wall is not high. • After excavating and digging the foundation, the soil must be levelled and compacted. • Foundation dimensions are custom-designed. • For walls which are more than six layers high, construct a concrete foundation. If walls are less than six layers high, the soil needs to be compacted and cement can be added. • Wet your concrete foundation regularly for 24 hours for better curing and to prevent cracking.
Soil compaction • Inadequate soil compaction is the most common cause of retaining wall failures, according to engineers. • The wall blocks are merely the “skin”. Compaction is what determines structural integrity. • Compaction needs to be done layer by layer behind the blocks. Lay one row of blocks and compact behind and inside them, blocks using a mechanical compactor or roller and a hand tamper respectively before laying the next row. • Every layer must be moist when compacted (neither dry nor muddy). • Ensure you achieve the compaction density as per design. Normally, this is 90-95% MOD ASSHTO.
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Packing • Make use of a string line or a dumpy level to pack straight walls. • Alleviate creeping on higher rows around corners by using half-blocks, when required. • Ensure blocks are level and not tilting or leaning in any way.
Use of Geotextile • Ensure the Geotextile is laid smoothly and does not “concertina”. • The Geotextile is placed over a block and then the next block which is placed on top of it anchors it in place. • It is good practice to allow the Geotextile to protrude a few millimetres, making it visible. The overhang is cut off after completion of the wall. • Geotextile can be used as a base to prevent soil from falling through the blocks in the open laying patterns.
Drainage Good drainage is essential to prevent water build-up. Without sufficient drainage, a dam is created. Always be on the lookout for excessive stormwater drainage flow and, if necessary, build V-drains 1,5-2,5m from the edge to channel surface water away from the retaining wall. • Drainage pipes must be laid in crushed stone and protected by Geotextile.
Design
Block height = 200mm
The most common measurement used by civil engineers to achieve the required construction angle is 750.
Degree 600 650 700 750 800 850
Technical specifications
Tie Back (mm) 115,5 93,3 72,8 53,6 35,3 17,5
Side on closed orientation 0,012 420 200 13,09 28
Side on open orientation 0,012 600 200 8,33 28
Front & back on closed orientation 0,012 300 200 16,67 28
Front & back on open orientation 0,012 523 200 9,56 28
500
500
460
460
Advantages Easiest to install Green wall Most aesthetically pleasing Disadvantages Possible creeping around Most economical Most expensive corners material cost material cost
Green wall
Volume Length (mm) Height (mm) Blocks per m2 Weight per block (kgs) Minimum wall angle from horizontal
Difficult to install
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Retaining walls: Installation Guidelines
Good installation practices
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Reality check The installation of retaining walls requires skill and meticulous attention to detail. The wall pictured above not only looks terrible, but is also likely to fail – and when a retaining wall fails, the consequences could be dire. It is critical to consult a specialised engineer and use a skilled contractor for the construction of retaining walls higher than 1,2m.
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Retaining walls: Design Concepts for Walls Lower Than 1.2m These retaining wall design concepts are based on the Bosun Robust Block and the Versoblock. NOTE: These design concepts are GUIDELINES ONLY. Consult an engineer before building Retaining walls. For walls lower than 1,2m an engineer certificate is not required under normal conditions.
Normal conditions Normal conditions can be defined as: • The area must have good, compactable soil (no sand or clay). • If the area does not have good, compactable soil, fill material should be imported (G5 or G6 is acceptable). • Care needs to be taken when building retaining walls to prevent injury or death. • No structural or vehicular loading. • No severe surface or groundwater in the area. Foundation: • Excavate to a depth of ±220mm. • Compact the soil 100mm below the intended concrete foundation to 93% MOD ASSHTO. • Construct a 400mm x 120mm, 20 Mpa concrete foundation – a concrete foundation will enable easier levelling. • The first block should preferably be placed 100mm below the ground level. Construction: • It is recommended that the wall be constructed at a 75° angle. • After each block layer, the soil should be compacted to 93% MOD ASSHTO. Do not compact layers more than 150mm thick. • Use a vibrating roller or jumping jack tamper for compaction. Any mechanical compaction must not be closer than 300mm behind the block. Compaction 300mm and closer must be done by hand in order to prevent blocks from tilting. • Install 40/40 composite reinforcing geogrid between every second row of blocks. The geogrid should be ±800mm from the front edge of the blocks. (It is recommended that you use RockGrid® by Kaytech). • The geogrid should be laid flat, without creases. For Bosun Versoblock installations, use a geogrid after every third block. • The most important aspect of retaining block walls is the compaction behind the blocks, together with the geogrid. The blocks merely act as the system’s “skin”.
Foundation detail
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For areas with moderate surface or sub-surface water The definition of normal conditions must be considered. Foundation: • Excavate to a depth of ±220mm. • Compact the soil 100mm below the intended concrete foundation to 93% MOD ASSHTO. • Construct a 400mm x 120mm, 20 Mpa concrete foundation – a concrete foundation will enable easier levelling. • The first block should preferably be placed 100mm below the ground level. Construction: • It is recommended that the wall be constructed at a 75° angle. • After each block layer, the soil should be compacted to 93% MOD ASSHTO. Do not compact layers more than 150mm thick. • Use a vibrating roller or jumping jack tamper for compaction. Any mechanical compaction must not be closer than 300mm behind the block. Compaction 300mm and closer must be done by hand in order to prevent blocks from tilting. • Install 40/40 composite reinforcing geogrid between every second row of blocks. The geogrid should be ±1 100mm from the front edge of the blocks. (It is recommended that you use RockGrid® by Kaytech.) • The geogrid should be laid evenly, without creases. For Bosun Versoblock installations, use a geotextile between every third block. • The most important aspect of retaining block walls is the compaction behind the blocks. The blocks merely act as the system’s “skin”. Sub-soil drain: • The sub-soil drain should preferably be installed ±600mm behind the blocks in order for water to flow into the drain, as opposed to the compacted area. • Use a 75mm perforated pipe, enclosed in 19mm or 6mm stone and wrapped in 150mm x 150mm A2 non-woven filament geogrid (Bosun recommends A2 Bidim® by Kaytech). • Fines will clog the system if a geogrid is not used. • Construct outlets every 6m to dispose of water at the lowest end of the sub-soil drain. V-drain or kerb: • The purpose of the V-drain is to direct water away from the retaining block wall. • The V-drain or kerb should be ±1,5m behind the top edge of the wall, in order to divert water from the compacted area.
Structural drain detail
* For more comprehensive details on design concepts or walls higher than 1,2m, refer to the website: www.bosun.co.za
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Retaining walls: Design Concepts for Walls Lower Than 1.2m Structural loads / Vehicular loads for areas with sufficient space The load should be at least 1,7m from the edge of the wall. The definition of normal conditions must be considered. Foundation: • Excavate to a depth of ±220mm. • Compact the soil 100mm below the intended concrete foundation to 93% MOD ASSHTO. • Construct a 400mm x 120mm, 20 Mpa concrete foundation – a concrete foundation will enable easier levelling. • The first block should preferably be placed 100mm below the ground level. Construction: • It is recommended that the wall be constructed at a 75° angle. • After each block layer, the soil should be compacted to 93% MOD ASSHTO. Do not compact layers more than 150mm thick. • Use a vibrating roller or jumping jack tamper for compaction. Any mechanical compaction must not be closer than 300mm behind the block. Compaction 300mm and closer must be done by hand in order to prevent blocks from tilting. • Install 40/40 composite reinforcing geogrid between every second row of blocks. The geogrid should be ±1100mm from the front edge of the blocks. (It is recommended that you RockGrid® by Kaytech.) • The geogrid should be laid evenly, without creases. For Bosun Versoblock installations, use a geotextile between every third block. • The most important aspect of retaining block walls is the compaction behind the blocks. The blocks merely act as the system’s “skin”. Sub-soil drain: • The sub-soil drain should preferably be installed ±600mm behind the blocks in order for water to flow into the drain, as opposed to the compacted area. • Use a 75mm perforated pipe, enclosed in 19mm or 6mm stone and wrapped in 150mm x 150mm A2 non-woven filament geotextile. (It is recommended that you use RockGrid® by Kaytech.) • Fines will clog the system if a geogrid is not used. • Construct outlets every 6m to dispose of water at the lowest end of the sub-soil drain. V-drain or kerb: • The purpose of the V-drain is to direct water away from the retaining block wall. • The V-drain or kerb should be ±1,5m behind the top edge of the wall, in order to divert water from the compacted area.
Foundation detail
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Structural loads / Vehicular loads for areas with limited space Loads should not be closer than 1m from the top edge of the retaining block wall. (Consult a civil engineer if the load is closer than 1m.) The definition of normal conditions must be considered. Foundation: • Excavate to a depth of ±250mm. • Compact the soil 100mm below the intended concrete foundation to 93% MOD ASSHTO. • Construct a 400mm x 150mm, 20 Mpa concrete foundation – a concrete foundation will enable easier levelling. • The first block should preferably be placed 100mm below the ground level. • Ref 193 Mesh or Y10 reinforcing can be added to the foundation, depending on the load. Construction: • It is recommended that the wall be constructed at a 75° angle. • After each block layer, the soil should be compacted to 93% MOD ASSHTO. Do not compact layers more than 150mm thick. • Use a vibrating roller or jumping jack tamper for compaction. Any mechanical compaction must not be closer than 300mm behind the block. Compaction 300mm and closer must be done by hand in order to prevent blocks from tilting. • Install 40/40 composite reinforcing geogrid between every second row of blocks. The geogrid should be±1 100mm from the front edge of the blocks. (It is recommended that you use RockGrid® by Kaytech.) • The last geogrid layer must be laid under the load foundation ±1 500mm from the top edge of the wall. • The geogrid should be laid evenly, without creases. For Bosun Versoblock installations, use a geogrid between every third block. • The most important aspect of retaining block walls is the compaction behind the blocks. The blocks merely act as the system’s “skin”. Sub-soil drain: • The sub-soil drain should preferably be installed ±600mm behind the blocks in order for water to flow into the drain, as opposed to the compacted area. • Use a 75mm perforated pipe, enclosed in 19mm or 6mm stone and wrapped in 150mm x 150mm A2 non-woven filament geogrid. • Fines will clog the system if a geogrid is not used. • Construct outlets every 6m to dispose of water at the lowest end of the sub-soil drain. V-drain or kerb: • The purpose of the V-drain is to direct water away from the retaining block wall. • The V-drain or kerb should be ±1,5m behind the top edge of the wall, in order to divert water from the compacted area. Foundation detail
* For more comprehensive details on design concepts or walls higher than 1,2m, refer to the website: www.bosun.co.za
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Information
Information
Things you should know about paving, prior to installation Delivery It is highly advisable for you and your installer to inspect our products upon delivery. In the unlikely event of either party disputing our contract of supply, this remains the best time to resolve such disputes, with the least implications to all parties.
Installation It is always advisable to use an experienced and reputable paving installer. Obtain references beforehand and please feel free to contact Bosun as well in this regard.
Pricing Please consider pricing very carefully and bear in mind that there are always reasons for a product or a contractor being comparatively cheaper. As a contractor, developer or home-owner, you will be spending a substantial amount of money on paving. Do your homework and bear in mind that the cost of an installation involves much more than the price which was initially quoted.
Maintenance Some claim that certain types of paving are maintenance-free, but this is a myth. Although in many instances little maintenance is required, it is advisable to at least replenish jointing sand by sweeping approved plaster sand over the paved surface from time to time. This costs very little, but will go a long way towards ensuring that a paving installation lasts for many years.
Installation according to the South African National Standard It is imperative that your paving is installed in accordance with SANS 1200MJ. Even the most superior manufactured product might fail if the installation is not done in accordance with SANS. Amongst others things, SANS 1200MJ specifies the quality of bedding and jointing sands and the method of installation. (For more information on SANS 1200MJ, please see page 153.) The Bosun five-year guarantee is conditional upon installation being done in accordance with SANS 1200MJ.
How residential paving has traditionally been sold Traditionally concrete paving bricks or “cement bricks” have satisfied the price-conscious segment of the market. Many paving contractors’ sales pitches sound something like this: “Clay bricks will cost you x amount. If you’re looking for something a little classier, simulated stone or ‘SmartStone’ is an option, but it’s more expensive. However, the cheapest option we can offer you is cement bricks.” This has changed over the years. Modern manufacturing equipment and increased technical proficiency have enabled concrete paving manufacturers to produce unique products and remarkable finishes at the upper end of the scale.
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Information: Paving Material Comparison
Paving Comparison Make an informed decision and know what you are buying. (Contact www.bosun.co.za for a more comprehensive comparison.) Below is a summarised comparison between the most common materials used for paving in South Africa: As advertised
Dry Cast Concrete (Bosun)
Wet Cast Concrete
Natural Stone
Clay
Tar
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What can be created
Possible outcome due to bad-quality product, bad installation or limitations of the material used
Ageing
Most suited for: Residential driveways Pool surrounds Patios Internal tiling Landscaping Pathways Commercial parking Commercial driveways Public roads Industrial driveways
Dry Cast Concrete ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Wet Cast Concrete ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Natural Stone
Clay ✓ ✓
✓ ✓ ✓
Tar
✓ ✓ ✓ ✓
✓
✓ ✓
In one word
Durability
Design
Natural
Clean
Road
Advantages:
Lowest cost of segmented materials. Dimensionally accurate and easy to install. Various shapes and sizes for a wide variety of applications. Durable.
An aesthetically pleasing alternative to brick. Re-creates the look of natural stone. Less damaging to the environment than natural products. Various shapes, textures and sizes.
There is a positive, fashionable perception regarding the use of “natural” products in building and construction. Natural stone can be beautiful.
Clay pavers have a natural appearance with very good colourfastness. Durable.
Low initial cost of installation. Smooth driving surface.
Be aware of:
Weathering of surface Obvious weathering of surface in the long in the long term. term. Some shapes of pavers are not “new” and exciting.
Lack of long-term consistency. Limited dimensional accuracy.
Limited options in colours, shapes and sizes. Not modern and exciting.
Aesthetically, tar is limited. Not suited to low-traffic areas or heavy vehicles turning sharply and slowly.
Most obvious possible post-installation imperfections inherent to the specific paving material:
Colour fading. Long-term abrasion. White efflorescence. Black efflorescence.
Colour fading. Long-term abrasion. White efflorescence. Black efflorescence.
Flaking or breaking. Staining and discolouration.
Spalling or chipping of edges. Very susceptible to white efflorescence.
Cracking and potholes. Needs a lot of traffic to assist expansion and contraction.
Most obvious possible manufacturing defects (mostly applicable when purchasing from suppliers):
Products are dimensionally inaccurate. Uneven edges. Colour inconsistency. Not SABS-compliant in terms of strength.
Dimensionally inaccurate products. Pin holes on surface. Not natural and sometimes irregular colours. Colour stains, especially on larger products. Weak products.
Products are dimensionally inaccurate. Soft material. Stone that flakes or breaks. Colour inconsistency.
Weak product, breaking or crumbling. Chipped products. Products are dimensionally inaccurate.
Bad engineering or composition of material. Cracking.
Most obvious possible defects due to bad/ faulty installation (mostly applicable when installed by an unqualified installer):
Complete site failure or pavers breaking and spalling due to earthworks. Unlevelled or irregular surface. Cement staining when installed with cement grouting.
Complete site failure or pavers breaking and spalling due to earthworks. Unlevelled or irregular surface. Cement staining when installed with cement grouting. Crooked installation lines. Failure of cement grouting.
Complete site failure or pavers breaking and spalling due to earthworks. Cement staining. Installation of chipped and irregular products. Crooked installation lines. Unlevelled or irregular surface. Failure of cement grouting.
Complete site failure or pavers breaking and spalling due to earthworks. Cement staining when installed with cement grouting. Crooked installation lines.
Site failure due to earthworks. As asphalt paving is “installed” in-situ, there are great risks involved compared with other paving materials produced in controlled factory environments.
Aesthetics:
Limited larger paver options. Limited textures. Many colours available, but limited realistic, natural options.
Many shapes, sizes and unlimited textures. Includes large pavers. Combinations which may be installed together. Natural colours.
Mostly available in square, rectangular or totally irregular options. Limited textures. Natural colours.
Limited shapes and textures. Mostly available as standard “bricks”. Limited colours.
N/A
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Information: Efflorescence
White efflorescence Efflorescence is the formation of salt deposits, usually white, on or near the surface of concrete and clay bricks, causing a change in its appearance. Apart from the discolouration, efflorescence is harmless. This is best described as being “a temporary skin problem and not a deep-seated disease”.
Efflorescence on Bosun Pavers In Gauteng efflorescence is most obvious in the rainy summer months, but may be observed throughout the year, especially in irrigated areas and after a sudden drop or rise in temperature. It can occur from within the concrete or from the sub-grade (soil below the pavers). Over time, efflorescence becomes less extensive and in most instances, it disappears completely. Lightcoloured pavers might show the deposit less than darker-coloured ones.
How efflorescence occurs Efflorescence is a natural phenomenon that occurs through one or a combination of the following processes: Chemical processes Formation of efflorescence can be the result of a reaction of concrete constituents with carbon dioxide and/or sulphurous gases. Physical processes The formation of efflorescence could be caused by a number of physical processes involving both salt and water transfer in and out of the concrete product, the aggregates used in installation and the sub-grade or earth beneath the pavers.
Removal of white efflorescence • • • • • •
Efflorescence is very difficult, but not impossible to remove. Irrespective of the method used to clean efflorescence, it could reappear (in some instances, more severely than before). In many instances, rain simply washes away white efflorescence. Others recommend dry brushing and the avoidance of water to clean effloresced pavers. Some recommend washing with clean water or a mild detergent. A proven, but risky method of cleaning efflorescence involves the application of a mild acid solution to the pavers (one part pool acid to 12 parts water). Thorough pre-soaking and post-washing with clean water are required when using this method. Pre-soaking reduces natural porous tendencies, limiting the depth of penetration of the cleaning solution. Post-washing is required to remove any residue of the acid.
Bosun’s take on efflorescence • Efflorescence is a natural phenomenon appearing randomly in most materials used for segmented paving. As mentioned earlier, it could even be caused by the earth on which the paving is laid. Bosun Brick and other companies are actively working to find a remedy for efflorescence. • Many paving installations have never been affected by efflorescence. Some have had efflorescence for a few weeks, while others have been affected for months. Sometimes efflorescence is recurring and in other cases, it happens only once. • Bosun Brick cannot guarantee efflorescence-free products (prior to- or post-installation). Bosun Brick’s comprehensive five-year guarantee therefore does not cover efflorescence. Remember, white efflorescence is usually a temporary problem.
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Black efflorescence
(Desert varnish or black attack)
Black efflorescence is the unpredictable, sporadic darkening of concrete, clay and natural stone. Sporadic darkening usually occurs within six months of installation and is extremely difficult to remove. This phenomenon occurs on pavers, bridges and buildings. Although various studies have been conducted on black efflorescence, the exact cause is still unclear. However, studies have found a correlation between black efflorescence and the moisture of the surrounding area in which it has been installed. The short-term solution is to replace the affected pavers and ensure adequate drainage of the sub-base during installation. Over time and as the pavers wear off, discolouration will occur, thus blending in with other discoloured pavers. Other forms of discolouration mistaken for black efflorescence include mould, algae, tyre rubbers and staining from bedding sand. White efflorescence
The same site 6 months later
Black efflorescence
Reality check The formation of efflorescence on a site (black or white) is linked to the earth’s water content beneath the paving. In areas where high water tables exist or where moist clay soils are prevalent, efflorescence is a common occurrence. Black efflorescence is usually common to specific geographical areas. A neighbour’s paving and adjacent concrete structures would give you an indication of the potential of your paving being affected by efflorescence.
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Information: Selecting The Right Contractor For structural soundness a paving installer should be asked questions based on the following in order to determine the likelihood of installations lasting for many years. CATEGORIES OF CONTRACTORS
A practical guide for selecting the right paving contractor
Type of contractor World-class
RiskyWorld Class
Consult the Bosun Installation Guide for comprehensive reasons for these procedures.
Will you dig up any soil?
This costs more
Will you construct a foundation layer with G5 material or similar?
For structural soundness
This costs more
Will you compact the foundation layer using a roller or heavy-plate compactor?
This costs more
Do you have a plan for drainage and water run-off? This costs more
Will you lay pavers and kerbs on edges in concrete and haunch it with concrete?
This costs more
Are you going to bed the pavers in moist bedding sand, screeded in sections?
This costs more
Will you have a plate compactor on site all the time when installing my driveway?
This costs more
For an aesthetically pleasing finish
Will you install flagstones on a concrete bed? Will you move pavers on site without tipping wheelbarrows?
This costs more
Will you draw pavers from different packs when installing?
This costs more
Will your cutting be clean, straight and accurate? This costs more
Will you grout my flagstones with special paving grout? This costs more
Will you have experienced supervision on site? This costs more
Will you remove rubble promptly? This costs more
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? ? ? ? ? ? ? ? ? ? ? ? ? ?
Incompetent
A paving installer should be asked questions based on the following in order to determine the likelihood of an aesthetically pleasing installation. CATEGORIES OF CONTRACTORS
A practical guide for selecting the right paving contractor
Type of contractor World-class
RiskyWorld Class
Incompetent
Consult the Bosun Installation Guide for comprehensive reasons for these procedures.
Will you have a toilet on site?
This costs more
Cleanliness and professionalism?
or a pleasant experience
This costs more
Good administration and systems? This costs more
Do you require a deposit? Will you try to substitute euality pavers with a cheaper product from an unreliable supplier?
Usually requires 50% upfront
This costs more
Can I contact the contractor, even after installation is complete? This costs more
Will the contractor take responsibility if things go wrong? This costs more
Conclusion
PRICE OF INSTALLATION:
MAKE THE RIGHT CHOICE:
? ? ? If the contractor wants more than Usually requires 50% upfront, you more than 50% upfront are at risk
? ? ?
MOST EXPENSIVE
A CHEAPER OPTION Generally these contractors walk a fine line in order to be price-competitive.
CHEAPEST
Paving installed by these contractors is guaranteed to last a lifetime.
Paving will last, but sagging, ponding and edge failures might appear very early on if any of the above aspects are not adhered to.
Paving is guaranteed to fail
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Information: Laying Patterns
Bevel Bond, Urban Small & Urban Slimline
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Bosun Cobble, Split Bevel Bond & Rio Rocoso Bevel
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Information: Laying Patterns
Interlocking Pavers
Citylock
Permeable Citylock
152
Smooth Ethnic, Urban Medium & Urban Large
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Information: Laying Patterns
Urban Range Combination Patterns
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Urban Range Combination Patterns
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Information: Laying Patterns
Waterwise
Paver layout Permeability Quantity
20% closed 20% 25 Pavers per m2
Paver layout Permeability Quantity
60% closed 4,2% 28 Pavers per m2
Paver layout Permeability Quantity
40% closed 15,7% 23 Pavers per m2
Paver layout Permeability Quantity
100% closed 0,2% 30 Pavers per m2
Paver layout Permeability Quantity
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80% closed 3,4% 28 Pavers per m2
Venetian Paver
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Information: Laying Patterns
Linneo Paver
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Information: Installation Guidelines These guidelines are based on SANS 1200MJ, the official South African specification for the installation of paving. Important: Earthworks (base layer preparation) are site-specific and fall within the scope of an engineer’s expertise. Bosun strongly advises that an engineer design any paving’s earthworks. This is imperative for commercial, public and industrial sites intended to carry heavy vehicular traffic.
Terminology: • Sub-grade is the prepared natural earth on which paving will be installed. • Sub-base is the prepared layer beneath the paving and bedding sand. (In South Africa it is usually “natural earth”, unless otherwise specified by an engineer. In other countries it is usually a special imported material, consisting of particle sizes between 40mm and dust.) • Bedding sand is the final layer upon which the paving blocks are installed. • Jointing sand is used for grouting between pavers. • Earthworks or base preparation (beneath the bedding sand.) • The soil conditions and application will determine whether a special sub-base is required. An engineer is required to calculate the need and specification. This will involve excavation and back-filling. • For domestic driveways and paving subjected only to pedestrian traffic, good-quality natural earth might provide sufficient strength for the installation of paving. (However, if you want your paving to last a lifetime, insist on an imported sub-base.) Sandy and clay soil conditions will always require a specially designed sub-base.
Compaction: • Good compaction of the sub-grade and sub-base is critical for your paving installation to last, whether you use an imported sub-base or not. Good compaction means compaction in layers and not merely the compaction of the top soil. In practice, this means taking out soil, compacting, putting some soil back, compacting, etc. • Hand-stampers and small plate compactors are simply not good enough to achieve good compaction. We recommend the use of a mechanical roller.
Bear in mind that: • Excavation is usually required on areas intended for paving. The extent of excavation is determined by the thickness of pavers to be used together with their bedding. • In most instances, excavated material will need to be removed from the site. • There might be natural depressions in the earth of the area to be paved and, depressions, special materials will be required to fill them. On residential driveways, excavated earth is generally usable. Bedding sand should not, in any circumstances, be used for this purpose. • All plant material and roots must be removed from the soil and site. • Carefully consider the roots of trees that might eventually grow under the paving. • Carefully consider underground utilities prior to excavation and digging. • After excavation, “drainage levels” must be checked and rectified.
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Information: Installation Guidelines Drainage: • Many paving failures are due to ingress of water into the earthworks beneath the paving. In order to eliminate this problem, pay attention to drainage. • It is imperative that there are adequate longitudinal falls and no undulations to prevent ponding and infiltration of water into the layer works, particularly in the first year after installation. A minimum fall of 2% in any direction is generally required. It is also important to ensure that the paving is laid proud of (ie 5-10mm higher than) stormwater structures or channels. • Where a high water table exists, sub-soil drainage should be installed. • Drainage channels and underground drainage pipes should be installed in certain areas, such as low points in steep driveways, around downpipes, etc. • Consider the natural land and buildings when designing a drainage plan.
Sub-base stabilisation: Sub-base stabilisation should be done in accordance with SANS 1200MJ when specified. In simple language, this requires cement to be mixed into the sub-base.
Edge restraints: • The earth preparation should extend to the rear face (back edge) of edge restraints. • Edge restraints consisting of kerbs or channels must be constructed on the subbase before paving is laid. In residential applications, an edge restraint might be constructed by laying the pavers on the edge in a concrete bed. (This is often called the header course.) • Experience has shown that the best edge restraints are kerbs. For residential and pedestrian applications, garden kerbs are ideal. There are many aesthetically pleasing options on the market. • On large paved areas and paving on steep slopes, additional restraints in the form of edge beams might be required. Please refer to the CMA manual for paving on steep slopes. • In-situ concrete on edges is not recommended as it usually breaks after a few months.
Bedding sand: • The incorrect selection and application of bedding sand is a major cause of site failures. • The sieve analysis of bedding material is specified in SANS 1200 MJ (the only South African specification for the installation of concrete paving). To simplify what is said in SANS 1200MJ, good-quality, washed river sand usually falls within this sieve analysis and is therefore recommended as default bedding material. • Cheap, inferior bedding materials will cause site failure. • Do not mix cement with bedding sand, unless specified by an engineer.
Bedding sand do’s and don’ts: • Bedding sand must be spread over the sub-base and evenly screeded in the loose condition so as to achieve an even thickness of 20-30mm. • For pavers larger than 250mm on one edge, we recommend a thickness of 40mm of bedding sand. • Do not compact bedding sand before laying pavers. • Where the sand bed is accidentally compacted before the units are laid, it must be raked and evenly re-screeded in a loose condition.
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Bedding sand do’s and don’ts (continued): • Bedding sand must be moist. (Not saturated with water – only moist.) • The sand bed must be laid slightly in advance of the placement of the units, but only to the extent that the particular area of paving can be completed on the same day. (With the sun baking down, it might be limited to a few hours at a time.) Therefore the moisture content of bedding sand should be continuously assessed on site. • Where bedding sand dries out, it must be raked back into a heap, moistened with water and shovelled in order to obtain consistent moisture. Only then must it be levelled out and screeded again. • Do not add water to spread out bedding sand. • Dried out or too little bedding sand will cause: - Uneven paved surface. - Rocking pavers that will break in time. - Grouting failures. - Pavers with chipped edges (spalling). - Do not use plastic sheeting beneath or on top of bedding sand. It does not prevent weeds from growing and badly affects the structural integrity of the paving.
Laying of pavers: • Where appropriate, lines must be set up at right angles to each other to control the alignment of the pavers. • Joint widths must be 2-6mm. • Nibs on pavers are generally 1-2mm in size. This is smaller than the joint widths, as specified by SANS 1200MJ. The ideal would therefore be to use nylon line as guides and leave grouting gaps larger than the paver nibs. • In other countries, it is specified that nibs be used as a guide only and that pavers be packed without touching at all. • In practice in South Africa, concrete pavers are always butt-jointed, with nibs touching adjacent pavers. Technically this is incorrect, but in reality, only paving artisans can do this and there are very few of them in South Africa. • Pavers from various packs should be mixed when installed. Installing pack by pack will result in a “patchy” finish. • Pavers should be transported in a paving cart or wheelbarrow prepared with blankets. They should not be thrown into wheelbarrows or front-end loaders and dumped, as this will damage them.
Cutting: • Whole units must be laid first. Precisely cut pieces should then be fitted into gaps which are too small to lay complete pavers in, such as those which are close to edges and around manholes. • The best practice is to mark pavers when they are packed out and to then individually cut them with a special paver cutter or masonry saw with a diamond-tipped blade. In reality, however, pavers are in many instances packed out, marked and cut with an angle grinder on the ground. When this procedure is followed, cutting will never be as accurate or neat as required.
Levelling (first compaction of pavers): • Compaction of pavers should be done while the bedding sand is still moist. It is a useless exercise on dry bedding sand. • All debris and sand should be cleaned off paving prior to plate compaction. • For Bosun unbevelled Large Urban Pavers, we recommend that compaction only take place after jointing sand has been swept into gaps between pavers. This will help to prevent edges chipping. In this instance, initial levelling should be done with a large rubber mallet, which is available from Bosun. • For any other pavers with bevelled edges, we recommend that at least two compaction passes with a mechanical plate compactor be made over the paving as soon as possible after laying, and before the introduction of any jointing sand. • By the end of each day, compaction must be completed to no closer than 1m from any free edge. A uniform, even surface should be obtained over the paved area. • To avoid damaging pavers, we recommend fixing conveyor belting onto the vibrating plate of the compactor.
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Information: Installation Guidelines • After compaction, lines should be checked and adjusted with a crowbar or special alignment tool. If necessary, these areas should then be re-compacted. • Temporary edge restraints should be used across the front laying edge when installations are to be continued on the next day.
Joint filling and second compaction of pavers: • The joints should not be filled until all cut pieces of paving have been inserted, all the necessary adjustments to the line and level have been made and the pavement has been subjected to at least two passes of the compactor. • Sand that complies with sieve analysis as specified by SANS 1200MJ must be used as jointing sand. In South Africa, plaster sand is usually close to the specified sieve analysis. • Avoid the use of red plaster sand for grouting, as it will stain your paving. Always use light-coloured plaster sand for grouting. • In other countries, silica sand is used as jointing material and is definitely the better option. (However, it is more difficult to obtain and subsequently a more expensive option.) • The most important aspect of jointing sand is that it should be bone-dry. (Moist jointing sand will not fill gaps between pavers consistently and will cause “bridges” that will collapse in time.) • Jointing sand should be broomed into the joints until they are filled and sufficient passes of a plate compactor should be made to settle the joint filling. (The jointing sand should literally be “shaken” into the joints by the plate compactor.) • The procedure should be repeated until the joints remain full after compaction. • On completion of compaction, all excess sand should be broomed off and disposed of. Damage caused during compaction should be compensated for by the contractor at his own expense.
Most importantly: • It is critical to sweep more sand into paving joints a week after the initial grouting. In many cases, grouting sand will settle and subsequently leave “groutless” gaps between pavers. It is not even necessary to use a plate compactor for this exercise. • Grouting sand should again be swept between pavers after six months of installation, or after the first heavy rains. This will fill joints and create good interlocking between pavers. If this is not done, there will be a chain reaction of grouting eroding and being washed out. This will eventually cause the pavers to be totally loose, resulting in site failure.
Cement grouting: In our opinion and according to SANS 1200MJ, cement should not be added to jointing sand. However, in South Africa it is common practice to grout paving with a cement slurry, rather than sand. This defies the principles of segmented block paving, as a solid “slab” is created. Cement grouting minimises certain risks and effectively “hides” certain potential problems. Generally, residential paving installations are done with cement grouting and because it carries light traffic, it usually works.
Where cement should be added to sand grouting: When paving on steep slopes. Around down-pipes. Along roof overhangs with no gutters.
Alternatives to cement grouting: There are specialised grouting options which work out to be more expensive than cement, but offer much more in terms of reliability and longevity.
Using the paving: Sand-grouted paving could be used by vehicles immediately after grouting. Cement grouted paving should not be used for seven to ten days after installation.
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Basic installation guidelines for Bosun flagstones • Lay Bosun flagstones on a concrete bed. Ensure the bed covers the entire surface area of the flagstone, without any hollows or voids. • Apply bonding agent to the back of every flagstone in order for it to adhere to the prepared concrete bed. • Use rigid grouting between the flagstones. Wet the grouting area before applying cement grouting and carefully work the mixture into joints. When done, immediately remove excess grouting material from the pavers with a sponge. Contact a Bosun representative or visit www.bosun.co.za for a comprehensive installation guide.
Reality check It is more difficult and costlier to install flagstones than standard-sized pavers and interlocking shaped bricks. If your installer charges the same price that he charges for small pavers, wyou should certainly expect problems on site.
A practical example of poor installation This small walkway was installed a year before these pictures were taken. • No compaction was done. • No proper edge restraints were created. • Plastic sheeting was installed under the paving. • Bricks were not from a SABS-approved supplier.
Although this path carries only light pedestrian traffic: • A section has started to collapse a few months after installation. • Edge restraints are breaking and paving on the edges will soon start to move apart. • Weeds are still growing. So much for the plastic sheeting!
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Information: Permeable Design Pro Software
Permeable Design Pro Software Design permeable interlocking pavements with ICPI’s Permeable Design Pro Software (PDP): • Integrates hydrologic and structural solutions. • Includes rainfall data for 12 major cities in South Africa. • Provides base thickness solutions from calculating inflow/outflow & traffic loads. • Design sustainable storm water management with PICPs. • Design solutions with CAD cross section outputs. The Permeable Design Pro (PDP) software application is used to develop permeable aggregate base and subbase thickness solutions for supporting traffic loads, and for water storage and infiltration. By integrating both hydrologic and structural solutions, PDP helps to ensure the intended performance of permeable paving systems. PDP was developed to assist civil engineers and landscape architects to design permeable interlocking concrete pavements (PICP). The application enables the user to design PICPs for numerous applications, such as, residential driveways, commercial walkways and parking lots, paved roads, as well as industrial paving applications. Permeable Design Pro includes rainfall data for 12 major South African cities, extensive documentation and help library, onscreen mouse-over advice, as well as input error-trapping for learners. PDP is available for purchase and download from www.permeabledesignpro.com, or alternatively it can be made available through Bosun.
Bosun’s Waterwise Permeable Paving Range Waterwise Heavy
Waterwise Citylock
Waterwise
View more on pages 94-96
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Information: Permeable Paving Installation Guidelines
Guidelines for successful functional and structural performance of Bosun permeable pavers. Please Note: This document is merely a guideline for the installation of the Bosun permeable pavers. Individual analysis and design of a specific site would have to be conducted by a qualified engineer. Bosun could be contacted in order to provide the services of a contracted industry expert in this field in order to assist engineers for a nominal fee. The Bosun permeable pavers bring a new dimension to aesthetic appeal and drainage capability of large areas used by pedestrian or vehicular traffic. Successful use, however, is dependent on proper design and installation. These guidelines assist practitioners in specifying and applying sound procedures. They are focused on specific requirements and are supplemental to general industry documents such as the Concrete Manufacturers’ Association’s (CMA’s) An Introduction to Permeable Concrete Blocks.
Managing water run-off Managing water run-off is a current environmental focus, as it manages surface water by attenuation and filtration with the aim of replicating, as closely as possible, the natural drainage from a site before development. Managing water run-off consists of: • minimising water run-off QUANTITY; • improving water QUALITY; and • providing AMENITY and biodiversity through an improvement of the environment. There are three permeable concrete block pavement (PCBP) systems, which are commonly known as Systems A, B and C. These systems possess different drainage attributes, but visually look the same. System A – full infiltration This system is suitable for existing soil (subgrade) conditions with good permeability and allows all the water falling onto the surface to infiltrate through the constructed layers to the water table, as shown in Figure 1. No water is discharged into conventional drainage systems, eliminating the need for pipes. This system is only suitable if the subgrade can receive the water without complications.
Figure 1. System A – full infiltration.
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System B – partial infiltration This system is used where the existing soil (subgrade) is unable to absorb all the water that falls on the surface. Surplus water is then removed by a pipe drainage system in the pavement structure, as shown in Figure 2. By the attenuation achieved in the permeable sub-base, run-off – and thus the danger of flooding – is significantly reduced.
Figure 2. System B – partial infiltration.
System C – no infiltration Where the existing soil (subgrade) is poor or contains pollutants, System C allows for the complete capture of all the rainfall, as shown in Figure 3. The porous nature of the sub-base functions as a storage tank, reducing peak flows through the outlet pipes leading to other surface drainage systems, such as ponds or water courses.
Figure 3. System C – no infiltration.
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Information: Permeable Paving Installation Guidelines
Design requirements Lower membrane: In Systems A and B, the lower membrane should be a permeable geotextile, to allow water infiltration. This membrane should have the required strength to withstand damage when the stone for the sub-base is placed, and it should remain permeable (not clogged) during the life of the facility. In System C the lower membrane is impermeable, since it is capable of being welded to ensure a complete seal and strong enough to withstand damage (such as holes punched into it) when the porous sub-base is constructed.
Sub-base thickness requirements: The permeable sub-base consists of a 26,5mm or 19mm single-sized crushed stone. This type of stone has about 40% of the volume of air voids, which means that 40% of the layer volume can be filled with water. If the layer is 150mm thick, it can accommodate 60mm of rainfall in the layer if there is no infiltration or outflow. This is sufficient for most rainfall events. In cases where more substantial requirements must be provided, advanced analysis techniques are available and Bosun can provide a service to assist designers. (We utilise the services of an academic in this field. The costs and timeframe of consultation would be determined by this individual.) From a structural perspective, a 150mm permeable sub-base is sufficient to carry 1 million standard 80kN axles during the life of the facility (about 25 trucks per day) on a subgrade with a CBR of at least 15. This is adequate for most applications in the urban environment, such as access streets, parking areas and hardstands around office and residential properties. For large projects or facilities carrying large numbers of heavy vehicles, where the implications of inadequate structural design are significant, detailed mechanistic design can be performed by specialist pavement engineers. Bosun offers a service to assist with the structural design or review designs, as mentioned above.
Construction of permeable sub-base and bedding layer(s): On Figures 1-3, a permeable geotextile membrane is shown as separator between the coarse stone and the bedding layer. From a functional perspective, a membrane is a feasible solution, but in practice this invariably causes problems. Before the membrane is placed, particle interlock of the coarse aggregate must be achieved by using a heavy roller with a mass of at least eight tons and preferably with vibrating capability. A one-ton walk-behind roller does not achieve particle interlock. The area to be paved must be completed so that the membrane can be placed (this is sometimes difficult to achieve on a small site). After construction of the paving, if trenching has to be done, the membrane is invariably pulled up and not reinstated after trenching is complete. An alternative to using a geotextile membrane, yet preventing the bedding sand from disappearing into the coarse stone layer, would be to select progressively finer materials. These materials are selected using the well-known filter criteria, which is explained below. The two aggregate materials should meet the following criteria: D15 sub-base D85 bedding layer must be less than or equal to 5. where Dx is the particle size at which x% are finer. Using the example in Figure 4, D15 sub-base is the size where 15% of the sub-base is finer, namely 8mm, and D85 bedding layer is the size where 85% is finer, namely 3,7mm. The ratio of 8/3,7 is 2,16, which is less than 5 and thus satisfactory. It is advisable to check visually on site that the laying coarse particles fit into the voids of the sub-base material without excessive migration into the sub-base.
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The bedding layer should have a thickness of 20mm to ensure that undue deformation does not take place, but adequate drainage occurs. The bedding layer is spread after complete compaction of the sub-base with a heavy roller to achieve full particle interlock. Compaction of the bedding layer is by means of a plate vibrator on the paving blocks.
Figure 4. Example grading characteristics of permeable sub-base (blue) and bedding layer (yellow).
Jointing material: The role of the jointing material is to ensure drainage through the joints in the paving blocks and to achieve “lock-up” in the paving system. “Lock-up” is when the paving blocks function as a unity and not as individual blocks, and provide structural strength. By vibrating the dry jointing material into the joints, load transfer between blocks is achieved. The joints in Permeable pavers are 3-5mm in width. The maximum size jointing material can thus be no larger than 2mm, as a rule of thumb suggests the maximum size to be two-thirds of the joint spacing. The jointing material should have no fine material passing the 0,425mm sieve. In the large squares of the Permeable paver, a 6,7mm single size stone can initially be placed to improve permeability before the jointing sand is added. The suggested materials fulfil the filter criteria and will not wash into the sub-base. Should the Permeable paver be used for aesthetic purposes and not for its drainage capability in a standard pavement, conventional jointing sand should be used in order to make the system impermeable.
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Information: Common Paving Installation Problems Most paving installation problems have a snowball effect, where one problem leads to another, causing yet another problem. This ultimately results in complete and irreparable failure of a paved area.
EARTHWORKS
EDGE RESTRAINTS
LEVELLING
Paving problems are mainly caused by inferior earthworks. When a paving site’s sub-base has failed due to incorrect earthworks, the result will be disastrous and irreparable.
Inadequate or inferior edge restraints will lead to movement and subsequent loss of jointing sand.
Uneven paving is unsightly and dangerous to walk on.
COMPACTION
BEDDING SAND
JOINTING SAND
Inadequate compaction of the sub-base will cause pavers to sag, resulting in water ponding, as seen in Drainage image below.
Inferior or insufficient bedding sand might cause pavers to move and break.
When jointing fails, pavers will move and edges, will chip or break. This might then lead to other problems.
DRAINAGE
CAREFUL HANDLING
CEMENT STAINING
Incorrect drainage will cause ponding, so that water infiltrates the sub-base, causing it to fail.
Careless and indiscriminate handling of paving will cause chipping and breaking.
Cement grouting can cause permanent stains on paving if the grouting is not correctly cleaned off the pavers.
CUTTING
ATTENTION TO DETAIL
SKILLED ARTISANS
Good cutting will create a beautiful effect. By contrast, bad cutting will be very unsightly.
If paved lines are not straightened and broken pavers are not removed, other problems could result.
Installing finishing touches is a skill. Small details, done incorrectly, can ultimately ruin an otherwise good installation.
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Information: Maintenance
Maintenance of Bosun Dry Cast Concrete Pavers Regular maintenance and good cleaning practices will enhance the overall appearance of your paving.
General cleaning of paving: Regular hosing and sweeping with a hard-bristled outdoor broom will not only keep your paving looking clean, but will also prevent weeds from taking root, as they usually grow where seeds are left undisturbed to germinate in the debris that accumulates between the pavers. If the paving is heavily soiled, use a general-purpose pH-neutral/slightly alkaline, non-abrasive cleaner. Ensure that all the soap has been thoroughly removed from the surface after cleaning and that the run-off of soapy water is channelled to drainage points or containers where it can be disposed of safely. Note: Do not use power hoses to clean paving, as this may wash out jointing sand and damage the grouting between pavers, ultimately damaging the pavers themselves.
Detergents: Bosun recommends specialised products like Tile and Floor Care (www.tfc.co.za). It is essential to seek expert advice and guidance. Bosun cannot accept any responsibility for inappropriate use and application of detergents.
Mechanical cleaners: It is recommended that sections of paving, at least, be cleaned daily in commercial pedestrian areas such as shopping centre piazzas and walkways. We also recommend the use of specialised equipment for daily maintenance of large paved areas. Tennant cleaning equipment is a respected option. We strongly advise you to consult an industry expert about the equipment which should be used on your site. Bosun cannot be held responsible for use of the wrong cleaning equipment.
The following recommendations relate to sweeping machines and associated equipment and their use: • Equipment should be custom-designed for sweeping a particular area. If there is any doubt, the equipment manufacturer should be consulted. • Tyres should be inflated according to the manufacturer’s recommendations to ensure maximum weight distribution. • Polypropylene, rather than wire brushes should be used.. • The brush pressure of the sweepers should be set to the minimum requirement for the particular task, ie surfaces swept regularly will require a lower setting than those swept infrequently or those covered with heavy deposits. • When sweeping, engine revolutions should be set to the minimum requirement to maintain vacuum (suction) pressure. • Operators, including temporary staff, should be trained according to the vehicle manufacturer’s recommendations. Tyre and brush pressures should be checked regularly. • Operators should be advised to switch off suction, brush rotation and water jetting equipment when machinery is stationary or left unattended, to avoid the risk of damage to the area underneath the equipment. • In new or re-laid areas, allowance must be made for the pavement to settle and the joints to seal before cleaning manually. • When using water jetting equipment to wash such areas, the jet or hand-held lance should be directed diagonally at the surface (ie not parallel to joints) at an angle of no more than 30°, using a suitable detergent solution. • The area should be inspected after cleaning to refill joints with jointing sand, if necessary.
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Information: Maintenance
Maintenance of Bosun Dry Cast Concrete Pavers continued Stain removal and spot treatments: Oil stains: As soon as the stain appears, dab excess spillage with an absorbent cloth or towel. Then remove the stain with soap, water and a brush. Ensure that all residue is washed away with hot water. Scuff marks from vehicle tyres: These marks can normally be removed by scrubbing the area with hot water and a strong detergent. Remember to rinse thoroughly. Rust stains, concrete, plaster and paint marks: Call in a cleaning professional to remove these particular marks on your paving, as attempting to do so yourself could cause damage to the surfaces. Beverage, smoke, fire and tobacco stains: These can normally be removed by scrubbing with hot, soapy water. If the stain is persistent, apply a mild bleach solution and then rinse the area with clean water, taking care to dispose of the run-off safely.
Weeds: It is a common misconception that weeds grow from beneath paving. This may occur in rare instances, but weeds almost always grow from seeds and bird droppings which land in the paving joints. Regular hosing and sweeping of the paved area will dislodge newly emerging weeds before they become fully established.
Maintenance tips: Inspect paving on a quarterly basis: Check for any loose, damaged or stained paving, as well as ensuring that the jointing material is intact. Loose paving: It is important to rectify the cause of the paving’s movement. Subsiding of the substrate layers is the most common cause of pavement failure. No matter what the cause, it needs to be investigated and rectified before replacing or re-bedding the pavers. Damaged or stained paving: Individual blocks can easily be replaced. See the Bosun website for further information on how to re-lay damaged paving. Jointing material that is no longer intact: The pavers simply need to be topped with jointing sand. This can be done by brushing or sweeping in approved dry plaster sand, where necessary.
Maintaining paving during construction: Paving should be kept covered during construction or renovation in order to avoid damage and possible staining from paint- or oil-based substances, as well as any harsh chemicals.
Sealing of block paving: Bosun recommends Cretesol. (www.cretesol.co.za). It is advisable to seek expert advice from an industry specialist. Bosun cannot accept any responsibility for inappropriate use or incorrect application of sealants. We strongly recommend that concrete products only be sealed six months after installation in order for them to fully cure on site and for possible efflorescence to run its course. It must be noted that sealants may have an effect on the colour of the paving and its slip/skid resistance. Sealants may also require ongoing maintenance during the life of the paving. In addition, it is important to ensure that the surface is dry, clean and efflorescence-free before any sealer is applied.
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Benefits of sealing your paving: • • • • • •
It improves its appearance. In certain circumstances, sealing prolongs the paving’s life. It helps seal the jointing material. It inhibits weed growth. It helps prevent stains (especially oil-based ones). If you choose to apply a sealant to your paving, call in a paving specialist to do the job.
Efflorescence: The white film that might appear on the surface of concrete, clay and natural stone products is called efflorescence. Apart from its discolouration, efflorescence is harmless. It is best described as a “temporary skin problem”, rather than a deep-seated disease. How does it occur? Efflorescence is a natural phenomenon which occurs through a complex chemical or physical process, or a combination of the two. Detailed information on efflorescence is available on the Internet, or consult the Concrete Manufacturers’ Association website (www.cma.org.za). Bosun’s take on efflorescence We are not bigger than nature. Bosun therefore cannot guarantee efflorescence-free products (either pre- or post-installation). We are constantly experimenting with aggregates and additives which might minimise or prevent efflorescence, although the soil beneath the paving could be the real reason this occurs. The Cure We believe that the best cure for efflorescence is simply to leave it, as it will eventually disappear. Experience has taught us that some paving installations have had efflorescence for only a few weeks, while others have been affected for months. Sometimes efflorescence is recurring and in other cases, it appears only once. It is therefore impossible to predict the outcome of a specific site. What we do know, however, is that efflorescence is temporary. If you Google “Remove efflorescence”, about 260 000 results appear. Most of them recommend washing the affected material with a weak acid solution. However, the efflorescence could reappear within a day. As noted above, one cannot control natural forces. Bosun believes that the use of acid is not a risk worth taking. However, if you do so, we recommend consulting the following British website page, for an objective and very comprehensive take on efflorescence, as well as options for removal: www.pavingexpert.com/eff01.htm Note: The information above on the cleaning and maintenance of precast concrete paving is only a general guideline and is not intended to be complete or comprehensive. It is particularly important that all cleaning methods be tested on a small, preferably inconspicuous area in order to determine their effects before applying them to a larger area.
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Information: Guarantee
Bosun’s five-year guarantee Bosun undertakes to replace, at its own cost, any of its products which are found to be defective in material or manufacture within a period of five years from the date of delivery to the customer.
Bosun’s liability under this guarantee is as follows: 1. The replacement of defective goods Bosun will replace defective products at its own cost. Bosun will pay the costs of delivering the replacement products to site, as well as for the removal of the defective products. 2. Other costs associated with remedial work Bosun will pay the direct costs associated with the replacement of defective products. Specifically, Bosun will pay for bedding sand (if required) and for the cost of labour required to uplift defective products, as well as their installation. Bosun is entitled to uplift only the specific pavers or kerbs which are defective and to replace them (as opposed to uplifting and replacing all the products).
Bosun’s liability under this guarantee does not extend to: 1. Defective installation Bosun’s liability under this guarantee is conditional upon the products having been installed in compliance with SANS 1200MJ. 2. Exposure to conditions beyond specification/industry norms Bosun is not liable for any product which fails as a result of its exposure to conditions beyond the specification for that product, or for any product which fails because it has been incorrectly specified or applied contrary to industry norms for such products. Bosun is not responsible for breakages that occur on site as a result of poor handling. 3. Indirect or consequential damages Bosun’s liability is limited to the express provisions of this guarantee. Accordingly (and without limitation), Bosun is not liable for penalties, consequential losses or any other indirect damages. 4. Failure by the customer to report defects to Bosun & to allow Bosun to replace the product Bosun’s promise is that it will replace and install products which are defective (according to the terms and conditions of this guarantee). The customer must immediately notify Bosun of any alleged defects in order for Bosun to assess the problem and, where necessary, take the necessary remedial steps. Bosun’s obligation to replace and install new products will immediately terminate in the event of any such remedial work being undertaken by the customer, owner or any third party other than Bosun, or its nominated contractor. 5. Efflorescence, colour variation and failure to maintain Paving products manufactured by utilising concrete may present with efflorescence. Similarly, over time, the colour on any product may fade. Bosun does not warrant that the products will not present with efflorescence or, over time, with a colour variation (from the original product). Accordingly, this guarantee does not extend to products which present with efflorescence, or which fade over time. Further, Bosun’s liability under this guarantee is conditional upon the product having been properly maintained. Sprawling and damage resulting from a failure to replace and maintain grouting consistency are not covered by this guarantee. Bosun conducts business in terms of its Standard Trading Terms and conditions (copies of which are available on request). This guarantee shall be read in conjunction with the Bosun Standard Trading Terms and Conditions, and (save to the extent that the terms of this guarantee are expressly at variance with the Bosun Standard Trading Terms and Conditions), the Bosun Standard Trading Terms and Conditions shall apply.
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Information: Complementary Products - Installation Tools
AVAILABLE AT BOSUN
String Tight System Straight and square edges are required when installing paving bricks, kerbs and slabs. Skew plumb lines are often a problem on site. The String Tight system provides a clearance of approximately 4-5mm between pavers and the string line. This is an essential tool for any contractor who lays paving blocks or carries out repairs to paved surfaces. It is adjustable to fit any size and shape of paver.
Paving Block Extractor
Kerb Laying Clamp
Paving Alignment Bar
Adjustable Paver Transport Cart
This is used to align the paving bricks before they are permanently set.
For the effortless transportation of bound or loose pavers.
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Information: Complementary Products - Installation Tools Paving Slab Handles These are used to handle heavy pavers such as Large and Slimline Urban Pavers. XXL Urban Pavers could be handled by a paving handle on each side.
Block-cutter
Universal Clamp
This cuts pavers up to 300mm wide in less than a second. Both blades, top and bottom, have four cutting edges, thus ensuring a long life. The blades can be turned quickly and easily.
An ideal tool for handling larger concrete paving slabs, kerbs and other related design components.
Unimobil (for hire)
Measuring and Marking Tool
The Unimobil is used to handle large paving units, such as the Bosun XXL Urban Paver.
An essential aid for the exact measuring and marking of lengths and angles on pavers.
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Information: Complementary Products - Grouting Solutions An alternative to cement grouting For more than 20 years, Romex has been the world’s leading manufacturer of paving jointing materials. Its high-quality, resin-based grouting solutions have been developed to overcome the shortcomings of cement grouting. Romex grouts are tried and tested and have been used on paving installations throughout the world.
AVAILABLE AT BOSUN
Romex resin is imported from Germany, but the specially graded silica sand used in conjunction with it is sourced in South Africa. It is therefore more expensive than cement grouting, but – when applied correctly – is guaranteed not to crack or break up. Benefits: • It is designed for a single purpose: jointing of paving. • It is reliable and long-lasting. • It does not crack or disintegrate. • It can be used for jointing repair jobs. • It has consistent, compressive, flexural and adhesive strength. • Its installation is fast and simple. • There is no staining. • It is resistant to weeds and digging ants.
Romex is easy to install in just a few simple steps:
1
4
Pour the two-part mix into the aggregate
Pour the mixture onto the area.
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2
5
Mix them together thoroughly.
3
Wet the pavers onto which the mixture will be applied.
Sweep the mixture into the grouting gaps. Ensure the mixture is evenly distributed.
6
Wash the excess Romex mixture off the pavers.
Information: Complementary Products - Sealants and Joint Stabilisers Sealing, stabilising and protecting your paving Since 1993, Resiblock Ltd, the block paving sealer expert, has sold block paving sealers. Whether it be for industry, commerce or home use, Resiblock solutions offer accelerated joint stabilisation without sand erosion or ongoing maintenance. AVAILABLE AT BOSUN Benefits of using Resiblock • Resiblock stabilises jointing sand and ensures that it is not eroded or washed out from between the joints. • Ensuring the stability of the jointing material will drastically increase the lifetime of paving. • Resiblock is ideal for areas with a steep slope or where joints are susceptible to erosion. • It is resistant to weeds and digging ants. • Its application is fast and simple. • Resiblock is not only a joint stabiliser, but also doubles as a high-quality sealer that will protect your paving from stains and scuff marks. Reasons for paving failure • Jointing sand keeps pavers locked. If this sand is washed out, it leaves empty spaces between pavers, enabling them to move and preventing them from remaining firm under traffic. • This leads to the failure of the sub-base. In wet conditions, the sub-base material will therefore be pumped out, as can be seen in the picture below. • Water has penetrated the paver joints and become trapped in both the sub-base and the sand laying coarse material. • Subsequent trafficking has led to the deformation. • Once saturated, both the sub-base material and the laying course material lost stability and proved insufficiently stable to support traffic. • The pavers have cracked as a result of the surface deformation.
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Information: Complementary Products - Cleaning and Protecting
Guard Remover Eco Efflorescence & Cement Suitable for most paving materials, Guard Remover Eco Efflorescence & Cement brings soiled paving back to its original state of cleanliness. It proves most effective in the rapid removal of cement haze, grout spillages, efflorescence and concrete laitance. Guard Remover Eco Efflorescence & Cement cleans paving in a minimally aggressive and non-corrosive way, when compared to other products on the market. This product was designed to meet the varying requirements of users applying it, in terms of safety, effectiveness, and the impact on the environment. It is an ideal product to be used in preparation for the application of paving protectors.
Guard Industry Paving Protectors Bosun supplies a range of Guard Industry paving protectors at various levels of protection to suit your requirements. Guard Industry paving protectors penetrate the pores of the pavers, making them impermeable and limit the absorption of water, oil, fat, grease, soil, and even graffiti. They offer long-lasting protection by slowing down the ageing of your paving and make it easier to maintain. Suitable applications include: driveways, patios, pool surrounds, walkways, high trafficked commercial areas as well as larger industrial applications. Guard Industry paving protectors do not go yellow over time and provide the option to enhance the appearance of the paving, or to retain the original colour. All these products are easy to apply with a low-pressure sprayer, a roller or a brush. Contact your Bosun Representative to discuss various protection options.
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Information: Building Information Modelling (BIM) Building Information Modelling (BIM)
Powered by:
We have partnered with leading BIM software developers, BIMsmith to provide you with BIM content for our premium concrete products. It is now easier than ever before to work with our products. All our content is developed in line with international standards, offering you reliable modelling information. We ensure to provide you with the best resources to design, build and manage the perfect commercial or residential space with Bosun products. Our BIM content is available to download through BIMsmith (https://market.bimsmith.com/), from the Bosun website, or alternatively they can be made available on request. Should you require further assistance, our Specifiers are on hand to provide a tailored solution. Please note that certain colours/finishes in certain product ranges are made to order – terms and conditions apply. Please consult your Bosun Specifier or Representative to confirm options and availability. Get started with Bosun BIM content in your Revit projects today.
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Information: Product Specifications Weight per pack
Pack dimensions WxLxH mm
120 60 240 60 528 330
792kg 720kg 1359kg 1380kg 1320kg 1320kg
800x 1200 x 550 800x 1200 x 550 800x 1200 x 720 800x 1200 720 800x 1200 x 670 760x 1200 x 730
132 88 14 360 220 424 12
1380kg 1440kg 1437kg 1240kg 1280kg 805kg 1188kg
800x 1200 x 820 800x 1200 x 670 900x 1200 x 1000 760x 1200 x 670 760x 1200 x 730 670x 1280 x 440 610x 10000 x 960
Thickness
Weight per Unit
Units / Pieces per m²
m² per pack
35mm 35mm 80mm 80mm 60mm 60mm 60mm 60mm 80mm 55mm 60mm
7,06kg 12kg 5,66kg 23kg 2,6kg 3,7kg 11kg 17,5kg 101kg 3,7kg 5,8kg
12,5 6,25 27,77 6,94 50 33,33 13 8,33 1,85 33 22,2
9.6m² 9.6m² 8.64m² 8.64m² 10.56m² 9.9m² 10.56m² 10.56m² 7.56m² 10.8m² 9.9m²
60mm 55mm
1,90kg 3,6kg
72,7 33,33
5.89m² 5.4m²
50mm 50mm 60mm 50mm 50mm 60mm 80mm
20,9kg 2,15kg 2,6kg 2,15kg 2,15kg 2,6kg 3,5kg
5 50 50 50 50 50 50
-
-
-
-
11.52m² 10.56m² 11.52m² 11.52m² 10.56m² 9.6m²
576 528 576 576 528 480
1240kg 1370kg 1240kg 1240kg 1300kg 1580kg
800x 1200 x 600 800x 1220 x 660 800x 1200 x 600 800x 1200 x 600 800x 1200 x 670 800x 1200 x 800
60mm 60mm 60mm
2,6kg 2,6kg 3,5kg
50 50 39
10.56m² 10.56m² 9.87m²
528 528 385
1300kg 1300kg 1340kg
800x 1200 x 670 800x 1200 x 670 980x 1150 x 660
80mm 80mm 60mm 60mm
4,5kg 3,73kg 3,5kg 4,35kg
39 50 385 Vary
-
-
-
-
9.6m² 9.87m² 9.87m² -
480 385 264
1475kg 1340kg 1200kg
TBC 980x 1150 x 660 900x 1000 x 680
100mm 100mm
35kg 12,26kg
4,2 13,55
4.65m²
40 63
1480kg 775kg
810x 1200 x 1000 600x 1200 x 700
300mm 300mm 250mm 250mm 280mm 280mm 175mm 175mm 200mm
110kg 36kg 80kg 26kg 105kg 35kg 86kg 27kg 107kg
200mm 150mm 125mm 150mm 280mm 150mm 300mm
36kg 12/24,8kg 72kg 60kg 120kg 55kg 115kg
-
-
12 36 12 36 12 36 12 24 12 24 100Units/50m 10 20
1188kg 1112,4kg 966kg 12936kg 1209,6kg 1126,8kg 1056kg 741,6kg 1239,6kg 864kg 1240kg 742kg 1246kg
610x 10000 x 960 750x 1000 x 900 620x 1000 x 800 610x 1000 x 840 750x 1000 x 900 750x 1000 x 950 840x 1000 x 950 620x 1000 x 830 840x 1000 x 950 620x 1000 x 940 760x 1000 x 770 610x 1000 x 700 800x 1000 x 850
6 25 12
720kg 200kg
-
600x 1000 x 580 810x 1000 x 800 800x 1000 x 940
155mm 100mm 23mm 200mm 200mm 250mm 80mm
26kg 13kg 375g 28kg 28kg ±49kg ±9kg
23.8 4 per LM
-
45 72
1170kg 936kg
740x 930 x 1000 670x 900 x 740
Units / Pieces per pack
Pavers Bosun Flagstone 200mm x 400mm Bosun Flagstone 400mm x 400mm Linneo 300mm x 120mm Linneo 600mm x 240mm Urban Small 100mm x 200mm Urban Medium 150mm x 200mm Urban Slimline 400mm x 200mm Urban Large 300mm x 400mm Urban XXL 900mm x 600mm Smooth Ethnic Paver Bosun Cobble Paver Venetian Paver Bullnose Pool Coping (10 per Linear meter) Cosmopolitan Coping (1,67 Per Linear meter) Bevel Bond Paver 60mm Bevel Bond Paver Split Bevel Bond Paver Rio Rocoso Bevel Paver 60mm Interlocking Paver 80mm Interlocking Paver Shale Interlocking Paver Rio Rocoso Interlocking Paver 60mm Citylock Interlocking Paver 80mm Citylock Interlocking Paver Waterwise Heavy (Permeable) Waterwise Citylock (Permeable) Waterwise Paver (Permeable) Grass Block Buffalo Block
Kerbs Figure 3 - 1000mm Figure 3 - 330mm Figure 4 - 1000mm Figure 4 - 330mm Figure 7 - 1000mm Figure 7 - 330mm Figure 8B Standard - 1000mm Figure 8B - 330mm Figure 8C Standard - 1000mm Figure 8C 330mm Figure 12 - 500mm (2x500mm Units) Figure 14 - 1000mm Channel Kerb - 1000mm Transition Kerb - 1000mm 150mm x 150mm Edge Beam - 1000mm Delineator Kerb -1000m
Retaining wall blocks VFC Retaining Wall Block VFC Retaining Wall Base Block VFC Locking Pin (Bar) Verso Block - No Lip Verso Block - With Lip Robust Retaining Wall Block Robust Block Slider
180
-
See p. 135 See p. 135 Open - 5.1 Closed - 9.09
5.1
-
-
-
-
24 24 18 108
681,6kg 681,6kg 882kg 972kg
850x 930 x 840 850x 930 x 870 750x 800 x 900 900x 750 x 700
Notes
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