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D) For a site with poor soil conditions and uneven bearing capacity, I would use a raft foundation. This raft foundation would be comprised of reinforced concrete and steel reinforcement beams. I have chosen to use a raft foundation as it spreads the load from the building evenly throughout the area it covers. It also reduces the load per unit area placed on the ground, which is very important in situations where ground conditions are poor, or the load is very large (Emmitt and Gorse 2010, p. 42.)1. This load is then transferred into the ground, using the whole area underneath the foundation. The steel reinforcement beams run in both directions under the whole floor area of the building, which provides extra strength and rigidity to the raft foundation. When the raft foundation is constructed, the vegetative topsoil layer must firstly be removed to provide a surface adequate for the raft to be constructed upon. Then a 50mm-blinding layer of concrete is laid down to provide a smooth, level surface for the steel reinforcement cage to sit on top of (Emmitt and Gorse 2010, p. 64.) 2. After the blinding layer has dried and set, the steel cage is constructed on top of it. This is tied together so as to stay positioned correctly when the next layer of concrete is poured on top. Next 150mm of concrete is poured and left to set. Now the steel cage is enclosed in the concrete raft, giving it reinforcement. For my floor I have selected three layers, which ensures that cold bridging is reduced, less heat is lost through the floor and water penetration is stopped. Firstly, on top of the raft, I have chosen to have a layer of impermeable insulation. This reduces heat escaping the building through the floor, and as it is impermeable, stops the rise of damp from the ground below to the room above. On top of the insulation sits a damp proof membrane (DPM). This is present to stop ground water penetration. The DPM must be sealed at all joints (taped) otherwise its functionality will be compromised (Emmitt and Gorse 2010, p. 65.) 3. As the DPM is on the warm side of the impermeable insulation layer, moist warm air is prevented from passing to the cold side of the insulation. If this was to happen interstitial condensation would form. This is where the water vapour that has diffused into the insulation gets trapped, compromising the thermal performance and lifespan of the material (Mirentxu Uulloa) 4. My final layer consists of a floating floor screed. A floating floor screed is “a screed laid on a layer of compressible thermal or sound insulating material” (Emmitt and Gorse 2010, p. 102.)5. This screed will be made in the ratio 1:1.5:3 (cement : fine aggregate : coarse aggregate) and will be a thickness of 65mm. These two factors will reduce the risk of the screed cracking whilst it is setting. To reduce this risk of cracking and drying quickly even further, a light mesh reinforcement will be included in the middle of the screed. At the edge of the flooring I have included edge insulation, to reduce the risk of cold bridging.

1

Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 3 Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 4 Mirentxu Uulloa, Interstitial condensation, available from https://www.educate-sustainability.eu [viewed 04/12/2012] 5 Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 2

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Plasterboard

Blockwork

D) Raft foundation and floor Fully insulated cavity

Skirting board Floating floor screed with light mesh reinforcement

Brickwork

150mm concrete reinforced with steel beams

E) A cold

Edge insulation DPM Rigid impermeable insulation board 50mm concrete blinding layer

roof can be defined as a roof that’s insulation is continuous up the cavity wall, over the eaves and on top of the ceiling (Emmitt and Gorse, 2010, p. 349) 6. Cold roof constructions are more commonly used than warm roof constructions due to the fact that less insulation is used. This is because the insulation is only laid across the top of, or between the ceiling joists; making it a more cost effective and more convenient way of insulating the roof space. The insulation used for cold roof construction is spread rolls, such as sheep’s wool or fiberglass. This is rolled in both directions completely across the top of the ceiling thus meaning there are no gaps in the insulation (Emmitt and Gorse 2010, p. 349) 7. Gaps in the insulation would cause a loss of efficiency in the insulator and therefore more heat would be lost from the building, which is not desirable. In cold roofs a vapour control layer (VCL) is used on the underside of the ceiling, to stop moist air from the warm side of the insulation (the room below) from passing to the cold side of the insulation (the empty roof space) (RIBA, 2012) 8. VCL is “any material that is sufficiently impermeable to prevent the movement of 6

Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 8 RIBA publishing; Roofing technical view; available from http://mycourse.solent.ac.uk/course/view.php?id=5955 [viewed 05/12/2012] 7

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moisture vapour without being an impenetrable barrier” (Emmitt and Gorse 2010, p. 351)9. Ventilation in a cold roof construction should be adequate to control the amount of air in the building, to prevent condensation. There must be a continuous opening of 10mm from the soffit vent, then through the loft vent tray into the roof space (Emmitt and Gorse 2010, p. 353)10. Cold roofs may also include ventilation through the eaves, ridge and in the roof slopes. Ventilation at the ridge allows moist air to escape at the top of the roof. In my alternative pitched roof construction, there are certain factors that differ from that of a cold roof construction, allowing the space to be used and for living in – a warm roof. In a warm roof thermal insulation is fixed above, between or below the rafters of the pitched roof (Emmitt and Gorse 2010, p. 350) 11. The advantage of this is that the roof space is warmed by heat rising from the heated rooms below, meaning the roof space should stay dry and warm, making it useable. In my detail I have fixed the rigid insulation in between the rafters and on top of the rafters (with no gaps in between the two layers). The insulation is tightly compacted together, leaving no gaps, covering the whole area of the pitched roof to, prevent cold bridging. On top of the insulation are counter battens that are nailed through the insulation and compact it tightly against the rafters. Bitumen roofing felt is then laid on top of the counter battens and the battens are nailed through the insulation into the rafters (BRE, 2002)12. The insulation is continuous from the roof and into the cavity, which is sealed with mineral wool insulation. In a warm roof the VCL is positioned differently to a cold roof. In a cold roof the VCL is positioned on the underside of the insulation in the ceiling. In a warm roof (and my detailing) the VCL covers the complete area under the insulation lining the roof (RIBA, 2012)13. This stops the moist air travelling through the insulation, forming interstitial condensation or condensation in the ventilation space, above the insulation. For the ventilation of a warm roof a 50mm continuous space is required between the underlay and the roof covering (in accordance with the manufacturers instructions) (BRE, 2002)14. This is 40mm more than in a cold roof. Ventilation is required at the eaves to allow the passage of air into and out of the ventilation space in the roof. Ventilation at the ridge can also be used with an air space of 10mm, as it is a restricted space where 50mm is not possible. Rigid insulation Tiles

Batten

9

Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 11 Emmitt S and Gorse C, 2010; Barry’s Introduction to Construction of Buildings; Wiley-Blackwell 12 BRE, 2002; Robust details report 262; available from http://mycourse.solent.ac.uk/course/view.php?id=5955 [viewed 05/12/2012] 13 RIBA publishing; Roofing technical view; available from http://mycourse.solent.ac.uk/course/view.php?id=5955 [viewed 05/12/2012] 14 BRE, 2002; Robust details report 262; available from http://mycourse.solent.ac.uk/course/view.php?id=5955 [viewed 05/12/2012] 10

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Counter batten

VCL

50mm ventilation Bitumen felt

Guttering

Insulation

Wall plate

Plasterboard

Fascia Soffit Mineral wool insulation Wall tie Brickwork

Plasterboard Blockwork Full fill cavity insulation

F(a) In this construction the floor will have to insulate airborne sound (vibrations) and impact sound (from touch). I have used a specific solution, which will do this effectively. I have decided to use a floating platform floor, with the ceiling supported independently. The ceiling is constructed of two layers of plasterboard, that make up the underside of the ceiling and a layer of insulation 100mm thick with a density of 10kg/m続 as required by building regulations (NBS, 2010) 15. The ceiling is supported separately from the floor above by independent joists. More independent joists support the floor. There must be a 100mm clearance between the ceiling and floor (NBS, 2010) 16. On the top of these joists sits timber raft boarding to hold the resilient insulation. This insulation is 25mm thick with a density of 36kg/m続 (NBS, 2010) 17. To support the flooring on top of this, I have chosen to use the Profloor Dynamic Batten 45mm x 55mm (A. Proctor Group, 2010)18. This batten is specially designed to support a floor finish, whilst reducing airborne and impact noise. It is therefore an ideal batten for this floor. Finally on top of the battens the floor finish is fixed on top. I have chosen to use timber raft 15

Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf 16 Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf 17 Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf 18 Profloor Dynamic Batten 2010; A. Proctor Group; accessed 10/12/2012 at http://www.proctorgroup.com/products/acoustic-solutions/profloor-dynamic-batten

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board as it is lightweight and strong. Profloor Dynamic Batten (PfD) Timber raft board

Joist

Timber raft board

Resilient insulation layer 100mm clearance Independent joist 2 layers of plasterboard

Insulation

F(b) The flooring for this junction is exactly the same as that in the previous part of the question. The wall I have decided to use is an external cavity wall with masonry inner leaf. The outer leaf will be made of brickwork and the inner leaf will be made of blockwork. This is because the cavity can be fully insulated, which helps to stop airborne sound being transmitted in and out of the flat. To support the joists on the wall, hangers will be used as the joists should not be built in (NBS, 2010) 19. These will be attached to the wall in between two rows of blocks (one on top of another) that are cemented together. Where two perpendicular plasterboards meet, they are sealed with sealant. This is to reduce flanking sound waves from passing through (NBS, 2010)20.

Plasterboard Sealed with sealant Timber raft board 19

Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf 20 Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf

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PfD Batten


Resilient insulation Timber raft board Joist Hanger

Brickwork Wall tie

100mm clearing Insulation

Full fill cavity insulation

Independent joist

Blockwork Plasterboard

2 layers of plasterboard Sealed with sealant

F(c) The flooring for this question is the same as in both previous parts of the question. For the specific type of floor I have chosen for this build, the separating walls need to be strong in order that they can support the joists on hangers. This is why I have chosen to use a solid masonry separating wall. The density of the blocks used for this wall must be 1840kg/m続 (NBS, 2010) 21 so that there is a sufficient barrier to airborne noise. On either side of the wall is a lightweight plasterboard. Where this meets the flooring it must be sealed with a flexible sealant to reduce potential flanking noise. The hangers for the joists are fitted on either side of the wall, at the same level in between two levels of blocks. These are then cemented into place with the next row of blocks laid on top. This is shown in my detailing.

Plasterboard

Sealed with sealant

Timber raft board

PfD batten

Resilient insulation

Timber raft board Hanger

Joist

Independent joist

Insulation

2 layers of plasterboard 21

Building Regulations Part E 2010; NBS; at accessed 8/12/2012 http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_E_2010.pdf

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Sealed with sealant


G) For this new industrial unit I have used a raft foundation. As I previously showed in question D, this foundation is suitable for the ground conditions that are present on the site and provides an adequate platform for the industrial building to be built on. For this industrial building I have decided to use a steel portal framed structure. My reasoning for using this construction method is that portal frames can by design, span a very large area that needs to be achieved in this build (Bird, 2012 A) 22. This will be coated with a galvanizing finish to stop the steel rusting. In between the frames, a secondary structure of “smaller, lighter steel sections” (Bird, 2012 A) 23 will be fitted and braced to provide extra strength and support to the framework. I have also used knee joints in the framework, to further increase its strength and stability. For the lower exterior of the building, I have used a dense masonry cavity wall. This is made up of a brickwork outer skin, a cavity, with full fill insulation and a blockwork inner skin. This is used as low-level protection to the steel portal frame (Bird, 2012 A)24. On the top of the cavity wall sits a steel cill that closes off the cavity, and a drip flashing, which water from above runs down and drips off. Fixed to the portal frame are sheeting rails, which the cladding is fixed to. In my detailing I have used steel Kalzip profiled sheet cladding (Kalzip, 2012) 25 with a galvanized finish. This is because it looks aesthetically pleasing and steel is a 22

Bird V, 2012 A; Walls 3 – Industrial cladding; accessed 12/12/2012; available at http://mycourse.solent.ac.uk/course/view.php?id=5955&topic=0#section-4 23 Bird V, 2012 A; Walls 3 – Industrial cladding; accessed 12/12/2012; available at http://mycourse.solent.ac.uk/course/view.php?id=5955&topic=0#section-4 24 Bird V, 2012 A; Walls 3 – Industrial cladding; accessed 12/12/2012; available at http://mycourse.solent.ac.uk/course/view.php?id=5955&topic=0#section-4 25 Kalzip, 2012; Corus Building Systems – Roof Properties; accessed 12/12/2012; available at http://www.kalzip.co.uk/files/CAD/uk/pdfs/RDS-A-1-04.pdf

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lot more durable than aluminum. The vapour control layer is fitted on the inner side of the insulation, which runs in between the cladding and the liner sheet. I have included steel guttering (finished with an organic coating) that is fixed to zed purlins at the eaves (Emmitt and Gorse, 2010) 26. Halter clips are fitted at the eaves to stop the top sheeting from moving down the pitch of the roof. The roof sheeting is fixed to the portal frame on zed purlins. I have also included insulation in between the zed purlins (Emmitt and Gorse, 2010) 27 to reduce heat loss.

26 27

Emmitt S and Gorse C, 2010; Barry’s Advanced Construction of Buildings; Wiley-Blackwell Emmitt S and Gorse C, 2010; Barry’s Advanced Construction of Buildings; Wiley-Blackwell

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Top sheet

Guttering

Insulation Insulation

Halter clips

Zed purlin

VCL Liner sheet

Zed purlin Portal frame Knee joint

Insulation

Portal frame Sheeting rail Kalzip profiled steel wall cladding Drip flashing

Steel cill

Blockwork

Brickwork Full fill cavity insulation

Screed with mesh reinforcement DPM

Concrete layer with steel beam reinforcement Concrete blinding layer

G) Foundation to roof detailing Alfie Simons Architectural Technology

Rigid impermeable insulation


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Summative assessment - construction technology