Woven | Chapter Five

W W O V E N

Over 100 years of industry knowledge

JA M E S D U N LO P T E X T I LE S. C O M

COVERIN GS

Wall coverings

CATHERINE MARTIN BY MOKUM / CHARLESTON PEARLS

CATHERINE MARTIN BY MOKUM / METROPOLIS WALLPAPER

WA L L

The purpose of this chapter is to give you a better understanding of key considerations and processes required for the preparation and installation of wall coverings to a professional standard.

Every effort has been made to provide necessary, in-depth and current information. However advancements in technology can change rapidly, therefore there may be material changes and new technologies that are not mentioned.

x

J A MESDUN L OPT EX T IL ES.COM

|

199

WA L L

JAMES DUNLOP / HIDE WALLPAPER

Contents: 1

Commonly used paper types

2

Commonly used printing techniques throughout history

3

Calculating wallpaper requirements

4

Difference between pattern repeat and pattern match

5

Essential preparation for a successful installation • • • •

6

correct preparation sealers size paste/adhesive

Installation guide •

installing paper based (paste the paper) wall coverings

•

installing non woven (paste the wall) wall coverings

7

Stripping wall coverings

8

Issues that can arise in wall coverings (along with remedies)

9

Wall covering care and maintenance

10

International wall covering symbols

2 0 0

Commonly used paper types Paper is measured in grams per square metre (GSM) and will typically be described by a number, i.e. 120, 130, 150 GSM, etc. A PVC vinyl on the other hand is made up of two distinct layers and consequently will be denoted by two figures, such as 80/90, 100/120, 120/200, etc. The first figure denoting the paper weight, the second the vinyl.

CATHERINE MARTIN BY MOKUM / METROPOLIS COLLECTION

I

n this chapter we look at the various paper types and printing techniques, along with pattern matching considerations. We cover the essential steps required for successful preparation and installation as well as various issues that can arise, along with suggested remedies. Appropriate wallpaper removal and specific care and maintenance advice is also discussed.

COVERIN GS

The logic of paper being measured by weight is in that it is not possible to accurately measure it by thickness. All paper is processed through a series of rollers during manufacturing that effectively squashes the sheet as thin as desired. However, the weight of the paper, regardless of how many times it is squashed, remains constant.

J A MESDUN L OPT EX T IL ES.COM

|

201

W O V E N

WA L L

UNCOATED PAPERS An uncoated paper is a wood fibre sheet that has no discernible surface coating on it. The face of the paper is therefore relatively rough when compared to coated papers. The paper face is calendered (flattened) to give it a degree of smoothness for printing.

Uncoated papers are normally valued and appreciated for their soft aesthetic qualities, as they are not particularly serviceable once hung. They should easily allow surface paste contamination to be wiped off during hanging, however no attempt should be made to remove surface glue once dry.

They’re generally best suited to a room that has relatively low pedestrian traffic and no moisture issue, e.g. living rooms, dining rooms or bedrooms.

NOTE: As a general rule of thumb, uncoated papers would be spongeable with a damp cloth.

JAMES DUNLOP / SOLITAIRE WALLPAPER

COATED PAPERS

x

A coated paper has the same fibrous backing layer as uncoated paper, but with a very smooth day/light vinyl coating laid on top that will readily accept the majority of print processes.

Coated papers are a good compromise between uncoated and heavy vinyls. They can be used in most environments as the coating gives a reasonable level of protection against moisture. However, it may not be appropriate to use them if the intended area is high in humidity, such as small, poorly ventilated bathrooms or kitchens.

They offer reasonable protection against the likes of grubby finger marks and general soiling and it’s possible that some of these marks may be removed using a soft

COVERIN GS

damp sponge and a mild detergent solution. Absolutely no abrasives or cleaning detergents should be used.

them particularly suitable for contract use, hotels, office blocks, hospitals etc., their opportunity for use around the home should not be underestimated.

It’s also unreasonable to expect them to withstand anything solvent based, such as pens, ink paints etc. Neither should there be an expectation for anything fatty, like cooking oil or peanut butter to be removed.

Another benefit of vinyl over paper is when the consumer chooses to redecorate. The PVC top layer is peelable and will pull off, if not in one complete strip, at least in big pieces. Once this is removed the backing layer can be made wet and easily scraped off.

NOTE: As a general rule of thumb, coated papers (light weight vinyl) would be washable.

NOTE: As a general rule of thumb, heavy vinyl wallcoverings would be washable or scrubbable.

PVC (HEAVY VINYL) COATED PAPERS PVC coated papers, or vinyls as they’re commonly known, consist of a heavy fibrous backing layer with a soft, flexible PVC coating laid on top.

The vinyl wallcovering is printed with the design when it is still in a smooth state; it’s not until after it’s been printed that it is ‘embossed’ to create the textured finish.

NON-WOVEN UNCOATED SUBSTRATES Non-woven, often referred to as ‘paste-the-wall’, products do not have paper as the base or web but instead are made of a synthetic blend, making this more dimensionally stable than the paper base products discussed above.

Vinyls have significant advantages when it comes to their performance on the wall. Vinyls are generally much heavier than standard papers because they have two layers. Given also that the top layer is PVC it makes the paper particularly easy to handle when hanging.

Non-wovens tend to have a comforting soft fabric-like feel to them and have the aesthetic qualities of an uncoated paper.

Their real benefits however, are in the hanging. Because there’s no expansion when adhesive is applied, there is no need to leave the paper to soak-out like conventional papers.

So you can paste the wall instead of the back of the paper. This allows it to be hung directly from the roll, making hanging more simple and less messy.

Vinyls are hard wearing and beautiful to hang, due mainly to the combined weight and strength of the PVC and paper layers.

Vinyls have a PVC coating that is resistant to moisture, and when used in conjunction with a light ready mixed adhesive they become particularly suitable for high humidity rooms, such as bathrooms and kitchens. They offer some degree of impact resistance and are therefore better suited than any of the other papers if there are young children in the house.

NOTE: Non-Woven Uncoated bases can be layered with a vinyl layer and be printed or embossed, just like the conventional paper based products discussed above.

Heavy vinyls generally have very strong fire ratings. Whilst this makes

J A MESDUN L OPT EX T IL ES.COM

|

203

W O V E N

WA L L

After each individual colour has been laid, the paper is hung for 4-5 hours to let the thick water based inks dry, before the next colour is applied. Once all of the colours have been printed the wallpaper is PVA lacquered for protection, before being manually trimmed and individually hand wound.

FLOCK (BLOCK PRINTED) Believed to have been introduced in the late 17th century. Flock wallpapers are traditionally produced using the block printing technique described above.

The difference being that one, or occasionally two, of the colours are substituted for rayon or wool fibres, giving the print a soft velvet like feel.

Commonly used printing techniques throughout history

BLOCK PRINTING The first known method of wallpaper printing, recorded as early as 1509. Prior to this, plain paper was pasted to the wall and then hand drawn and coloured in by artists. Block printing continued as the only ‘real’ means of printing wallpapers until the introduction of the printing machine some 300 years later.

Traditionally uses carved wooden blocks that are inked before placing the block exactly into position and pressing onto paper.

Accuracy and strength of colour is effectively governed by the printers ‘gut feeling’ on how much pressure to apply to the back of the block.

2 0 4

PAN (TROUGH) PRINTING CATHERINE MARTIN BY MOKUM / LA PALMA WALLPAPER

There are a plethora of design styles and printing techniques for wallpaper. Below we outline the printing processes that are, or have been, commonly used for the mass production of wallpaper within the industry over the last 500 years.

The paper used for flock printing is heavier than standard wallpaper, normally by around 25-35%, this is due to the heavy nature of flock and that a standard paper would not hold the weight.

Introduced mid 1500s as a means of evenly colour washing the background of wallpaper for block printing onto, a process having previously been done by hand.

Pan printing is a simple process, whereby the ink sits in an elongated trough with a sieve like base which spans the width of the paper. The sieve allows ink to pass through and cover the paper, which is being rolled underneath the trough at a controlled speed.

It is the fluidity of the ink that governs how much colour is applied to the paper.

Whilst pan printing is a process in its own right, it is more often than not used as a backdrop to other processes, the most common of these being block printing.

SURFACE PRINTING Invented in 1839, surface printing continued as the only mechanised means by which to print wallpaper

COVERIN GS

next position, where the process is repeated. It is important that the inks are allowed to fully dry before any subsequent screens are placed on top.

for the next 100 years. It was responsible for making wallpaper available to the masses and its immediate success marginalised block printing.

The machine consists of a large drum cylinder, approximately 1.5m in diameter, with print ‘stations’, generally between twelve to twenty stations, spaced around the circumference. The print cylinders are made of a very hard ‘ceramic’ type rubber and the area that you don’t want to print is cut out from the surface, leaving the printing surface ‘proud’ on the cylinder. The paper is fed around all printing stations. The inks are water based, and because water doesn’t evaporate in the same rapid way as a solvent does, it is still wet when the paper reaches the next printing station. This process of wet ink falling on wet ink creates an effect whereby the colours lightly “bleed” into each other, giving the quintessential soft visual finish of this printing process.

NOTE: Traditionally screen printing was called ‘Silk Screen Printing’ because the stencil screens were made of silk. This term has carried into modern times despite the fact nylon is now commonly used as opposed to silk.

ROTARY SCREEN PRINTING Introduced soon after flat bed screen printing, in the early 1950’s. The process allows a similar look to flat bed screen printing however it can print a continuous web of moving paper, upwards of 3000 metres long, as opposed to the limiting length (normally 30 metres) of flat screen printed wallpaper.

NOTE: Whilst rotary screen printing may, in principle, be similar to flat bed screen printing, it is significantly cheaper due to gained efficiencies in continuous print manufacturing.

FLAT-BED SCREEN PRINTING Introduced as a means for printing wallpaper in the early to mid 1940s. A print process using a flat rectangular shaped frame with a mesh stretched across it. To create the design it is first necessary to completely coat the screen with a photosensitive polymer. The stencil of the design is then placed flat onto the mesh before the screen is ‘photo-exposed’ under special lighting to harden the polymer into an impenetrable lacquer. The screen is placed face down onto a length of wallpaper, and the thick water based inks are applied to the back of the screen. The inks are drawn across the mesh using a rubber squeegee, forcing the ink through the areas of open mesh in the shape of the design.

Once the colour is laid, the screen is lifted and moved along to the

J A MESDUN L OPT EX T IL ES.COM

FLEXOGRAPHIC PRINTING Introduced in the early 1960’s.

Similar in principal to surface printing; in that it’s a relief type print process that uses a relatively soft rubber print cylinder with a ‘raised’ printing surface. Print stations are equally spaced around the outside of a large cylindrical drum that carries the paper, face out, around it by a series of rollers. In keeping with most relief type print processes the cylinders lay down a single flat colour, however advances in technology have resulted in flexo rollers that now produce a reasonable degree of tonal work.

|

205

W O V E N

The design screen used for gravure printing is a highly polished engraved cylinder with a thinly laid, soft copper coat wrapped around it. This copper coating is engraved with the desired design through creating microscopic cells/ holes that fill up with ink.

It is not uncommon for there to be tens of thousands of cells per square inch. Excess ink is scraped off the cylinder surface before the cells release their cargo of ink onto the paper. The depth and width of each cell determines how much ink is applied to the paper and subsequently the strength of colour. The shallower the cell, the lighter the colour and vice versa.

The major benefit of Gravure printing is the ability to print fine tonal work and graduation of colour using a single cylinder.

out of the machine into a lightproof container and taken to a "processor" where the paper is "developed" via a series of photochemicals. The paper emerges from the processor dry and ready for the next step, lamination.

Lamination is the process of coating the photographic media with a thin, protective, UV resistant sheet of plastic to protect the light fastness of the image, and guard against scratches, fingerprints, and moisture damage.

Digital printing can be accomplished using various methods: •

Dry Transfer Printing

•

Dye-Sublimation (Thermal Transfer) Printing

•

Inkjet Printing: Printing that fires extremely small droplets of ink onto paper to create an image.

•

Laserjet Printing

•

Electrostatic Printing

•

Grand Format Printing

•

Digital Photographic: When properly produced, the end result is a true photographic reproduction from your digital file, free of visible dots.

DIGITAL PRINTING Digital printing is the latest printing revolution. It can be used to produce large scale designs, designs with many layers of colour and designs that are not restricted by the roll width in terms of their pattern repeat.

The manufacturing process begins with a digital file, created using digitally generated, scanned, or photographic imagery. The original design, whether a pattern, photograph, graphic design or combination of all three, is electronically prepared for digital printing. At the printing stage, the printer converts your digital file information to pixel data. A photosensitive media (photographic print paper) is then fed into the machine in preparation for printing. Some machines use lasers for exposing the paper, while others use light emitting diodes (LEDs).

As the paper traverses under these light sources, the paper is exposed. The paper is then fed

HEAT EMBOSSING PRINTED VINYLS The purpose of heat embossing a vinyl is to convert a smooth plastic wallcovering into a wallcovering that is three-dimensional. A general misconception when it comes to PVC vinyls, is that the paper is printed in the conventional way and then a thin layer of PVC (polyvinyl chloride) is spread on the surface afterwards for protection. This is not the case.

Vinyl wallpaper enters the start of the print process with a smooth layer of PVC laid onto a backing layer, normally paper. At this stage the solvent based ink pigments

2 06

COVERIN GS

adhere well to the PVC but it is not until the whole sheet has been heat embossed that is becomes ‘fused’, effectively making the inks a part of the coating itself.

An embossing machine is not a part of the print process but is a process in its own right. It principally has three stages of process; heat (for softening the PVC layer), impression (textured steel roller impressed into the PVC) and cooling (to help form the new shape).

There are generally two types of vinyl: 1. Solid PVC vinyl – the vinyl is heated and squeezed between pressure rollers to emboss the desired pattern.

2. Blown PVC vinyl – the vinyl layer contains a ‘blowing agent’ which is a heat activated ingredient that expands rapidly when it is warmed up, making a thick foam like layer. This is useful where a very deep emboss is required without using an expensive thick solid vinyl.

CATHERINE MARTIN BY MOKUM / MAJORELLE WALLPAPER

GRAVURE PRINTING

WA L L

Blown PVC is subcategorised into two types: 1. ‘Mechanically’ blown vinyl – in this process the thick foam like layer is squeezed between pressure rollers to crush and emboss the desired pattern.

2. ‘Chemically embossed’ blown vinyl – in this process, the expandable ‘blowing agent’ doesn’t undergo the pressure rollers to emboss the design. Instead, the printing ink contains a chemical inhibitor that neutralises the expandable blowing agent.

Therefore when heated, the pattern (created with the chemical inhibitor/printing ink) doesn't expand, whilst all other surface area does. This creating an embossed look.

J A MESDUN L OPT EX T IL ES.COM

|

207

W O V E N

Calculating wallpaper requirements In order to calculate appropriate wallpaper requirements for a job, it is recommended to ignore windows and doors and treat walls with them as full walls. It is likely that as much paper will be used cutting and piecing around the recesses as would be used on a straight drop.

CALCULATING NUMBER OF DROPS NEEDED 1. Start by measuring each individual wall, from corner to corner, to determine the wall width.

2. Divide the width of the wall by the width of the roll to determine how many wallpaper drops/widths are required for that wall. Continue this for all the walls and total up all the drops together to calculate the total number of drops needed for that room.

NOTE: Remember that full widths of wallpaper should not be turned into a corner as walls are never even and creasing may occur.

Only 2 - 3 cm should be turned into the next wall.

For purposes of calculation, any part widths should be calculated as full widths.

WA L L

NOTE: If selecting a wallpaper that has a ‘random’ or ‘free match’, or is recommended to be ‘reverse hung alternate lengths’, there is no need to add on the pattern repeat when calculating the drop length.

CALCULATION EXAMPLE:

CALCULATION EXAMPLE:

Wall length: 3.5 m

Wall height: 2.5 m

Wallpaper width: 52 cm

Trim waste: 15 cm top 15 cm bottom

350 cm ÷ 52 cm = 6.7 widths of wallpaper Rounded up to the nearest full width = 7 drops required.

CALCULATING LENGTH OF DROPS 1. To calculate the length of full drops required, measure the height to be decorated and add to this 30 cm (15 cm top and bottom) for trimming.

Then add on the pattern repeat as identified in the pattern book or on the label, e.g. 52 cm.

2. Once the total required length has been calculated, divide it into the length of the roll (normally 10 metres). This will identify how many drops can be achieved from a full roll.

Remember to only count full drops.

2 0 8

COVERIN GS

Distance around the room (including doors and windows) Wall height from skirting

9m 10m 12m 13m 14m 15m 16m 17m (30') (34') (38') (42') (46') (50') (54') (58')

18m 19m 21m 22m 23m 24m 26m 27m 28m 30m (62') (66') (70') (74') (78') (82') (86') (90') (94') (98')

2.15-2.30m (7'-7'6")

4

5

5

6

6

7

7

8

8

9

9

10

10

11

12

12

13

13

2.30-2.45m (7'6"-8')

5

5

6

6

7

7

8

8

9

9

10

10

11

11

12

13

13

14

2.45-2.60m (8'-8'6")

5

5

6

7

7

8

9

9

10

10

11

12

12

13

14

14

15

15

2.60-2.75m (8'6"-9')

5

5

6

7

7

8

9

9

10

10

11

12

12

13

14

14

15

15

2.75-2.90m (9'-9'6")

6

6

7

7

8

9

9

10

10

11

12

12

13

14

14

15

15

16

2.90-3.20m (9'6"-10')

6

6

7

8

8

9

10

10

11

12

12

13

14

14

15

16

16

17

3.05-3.20m (10'-10'6")

6

7

8

8

9

10

10

11

12

13

13

14

15

16

16

17

18

19

Pattern repeat: 52 cm (250 cm + 30 cm + 52 cm = 332 cm) Total drop lengths = 3.32 m 3.32 m 10 metres (roll length) = 3 full drops per roll

CALCULATING NUMBER OF ROLLS NEEDED Simply divide the total number of drops needed for the room, by the amount of drops achievable from a roll. This figure is the total amount of rolls needed.

For designs with a pattern match of up to 26 cm add 10% up to the nearest full roll, for wastage. For designs with a pattern repeat of over 26 cm add 15 - 20%.

NOTE: This guide assumes that domestic length and width wallpaper is being used, normally 10 metres by 52 cm. It also assumes that there is no match on the wallpaper, i.e. it is either a ‘free match’ or ‘random match’ or is ‘reverse hang alternate lengths’.

J A MESDUN L OPT EX T IL ES.COM

|

209

WA L L

COVERIN GS

PATTERN REPEAT: The pattern repeat is identified by a written figure (e.g. 26 cm, 52 cm, etc) and is the distance measured before the same part of the design repeats itself along the length of the wallpaper.

Difference between pattern repeat and pattern match

JAMES DUNLOP / IMARA

It would appear that the understanding of pattern match and pattern repeat is one of the more difficult areas of wallpapering. Understanding the pattern repeat is particularly relevant when calculating how much wallpaper is required. Probably the biggest misconception is that pattern repeat and pattern match are the same thing, just different words.

This is not the case and it needs to be clearly understood that pattern repeat can be very different from pattern match.

NOTE: This measurement is useful for calculating how much extra should be allowed on each drop of paper on hanging. The amount of waste to be added to a length to be hung can never be greater than the pattern repeat indicated.

This distance can vary and is dependent upon how many times the design is engraved onto the circumference of the print cylinder or screen.

As an example and for description purposes only, we will assume that the circumference of a print cylinder is 60 cm. If the same part of the design was engraved into the cylinder four times, it would mean that the circumference of the cylinder (60 cm) is divisible by 4, hence the design repeat would be every 15 cm.

If the design repeats itself 3 times, it would be 60 cm divided by 3, thus creating a pattern repeat of 20 cm.

Or it may repeat itself only once, therefore the design would have a 60 cm repeat.

J A MESDUN L OPT EX T IL ES.COM

|

211

W O V E N

WA L L

COVERIN GS

PATTERN MATCH: The pattern match will generally be shown in one of three ways:

FREE MATCH / RANDOM HANG

STRAIGHT MATCH / HORIZONTAL MATCH

There is no point in which the pattern matches across rolls. Often used with vertical stripe or heavy textured designs.

The matching half of the design is on the same horizontal line as the next hung length.

HALF DROP / OFFSET MATCH

REVERSE HANG ALTERNATE LENGTHS

The match falls somewhere between the pattern ‘repeat’ on the opposite side of the wallpaper.

Hang every second (alternate) length upside down.

1. Written direction: e.g. half drop, free match etc.

2. As a symbol

3. Or as a combination of both

Its purpose is to identify where, in relation to the other side of the wallpaper (across the width), the matching part of the design is. To help with this you will find that in most cases wallpapers are trimmed through the design for ease of matching on hanging.

In a lot of cases (and this is where confusion may occur) manufacturers may use the words ‘pattern match’ on the label, but actually show the repeat against it, or vice versa. Next we outline the four common pattern match descriptions.

NOTE: If the matching half of the design falls on the same horizontal plane as the other side, then it is a straight match. If, on the other hand, the matching part of the design falls some-where between the two matching points, in relation to the other side of the sheet, then it is an offset match or half drop.

2 12

J A MESDUN L OPT EX T IL ES.COM

|

213

W O V E N

Essential preparation for a successful installation PREPARATION IS KEY Correct preparation is crucial in the achievement of a satisfactory installation and the preparation can be said to be more important than the actual hanging of the wall covering itself.

The tradesperson must have the knowledge and expertise to carry out both the preparation and the installation. It is easy to blame the wall coverings when something goes wrong, but first look at what time and effort has been spent on the preparation.

Four essential steps towards a successful installation: 1. Ensure all wallpaper roll details are thoroughly checked before proceeding.

2. Wall preparation is completed to a high standard appropriate to the paper being hung.

3. The correct type and amount of paste is used.

4. One roll is hung and checked by the installer, which is then signed off by the client before proceeding.

Over the years there has been much debate about whether or not to use oil based pigmented sealer as part of the preparation process for some surfaces that are to be wallpapered. Most of the opposition against using pigmented sealer has resulted from negative experiences of the wallpaper failing to adhere properly, usually at the seam area, where they can lift. This outcome is not the fault of the pigmented sealer but the result of poor preparation of the sealed surface prior to hanging the wallpaper.

Often people have redecorated kitchens and bathrooms previously painted with many coats of high gloss enamel and these areas have been very successfully wallpapered.

This is only because the surface was correctly prepared before the paper was installed.

Any lifting of the wallpaper is a breakdown in the adhesion caused by the lack of an adequate key, i.e. sanding with the correct grit of sandpaper (80 g) then dusting the entire area.

The choice of sealer is very important. Some sealers will dry to a greasy finish, some to a glossy finish. A sealer that dries to a matte (flat) finish is best.

Five essential preparation steps: 1. Sealers should be thinned slightly to ensure full penetration into the wall lining.

2. Once the sealer is applied, leave it to dry and cure for as long as possible.

2 14

3. The entire surface must be sanded with 80 g sandpaper to provide a good and adequate key to ensure adhesion.

4. The surface should then be dusted to remove all dust particles.

5. Give a good even coat of size before hanging.

A pigmented sealer should be used when installing semi-transparent wall coverings, to minimise ghosting or show through. This is where uneven colourations on the substrate are telegraphed through from behind the wall covering to the decorative face of the product, showing as stains.

The same applies when hanging non woven paste-the-wall products as these are in fact polyester not paper which do not have the same blocking power as paper.

COVERIN GS

SIZE Why should wall surfaces be sized prior to hanging wallpaper?

Sizing a surface during the preparation process gives both the paper and the paperhanger several advantages: • Acts as a sealer by stopping the moisture from the paste being sucked into the substrate.

JAMES DUNLOP / LORIANE WALLPAPER

OIL BASED PIGMENTED SEALER

WA L L

• Adds to the adhesion by working with the paste to adhere the paper to the wall.

• Gives a longer wet-life to the product, so the product stays workable for longer.

• Gives more slip and slide which makes it easier to position the product.

• Helps to hold down the seams.

• Helps to prevent seams/joins from opening during the drying process.

• Makes it easier to remove the product when it comes time to redecorate.

• Protects the wall surface during the stripping process.

Two different types of size:

NOTE: Do not use undercoat as a sealer under wallpaper. Some undercoats contain oils that can have a negative reaction to the adhesion of the new wall covering. While both contain oils, the undercoat oil is designed to cover a pigmented sealer. The oil pigmented sealer on the other hand is designed to penetrate the wall surface.

1. Powdered/granulated - both good general sizes compatible with most wall covering pastes including tub paste.

NOTE: Tub paste can be diluted to use as a size, acting in the same way as powdered/ granulated size.

2. Latex premixed size - this product is the ultimate in assisting the paper to adhere to the wall. It

is the only size that reactivates or re-wets, giving a much better bond between the paper and the wall and it helps eliminate edge lift and springing joins.

TIP: Always dust a sanded surface – Failure to dust a surface after sanding means that when the surface is sized, the size and the dust will mix, creating a rough surface when dry. This negatively impacts on the adhesion of the product to the wall, resulting in the paper failing to stick and lifting, especially at the seam/join area.

All size has wall life: • Size on the wall can have an active life of as little as 3 days, with a maximum of 5 days after which the surface should be resized.

• Size has a pot life – Once mixed, size can only be active for as little as 24 hours with a maximum of 48 hours, after which time the size should be discarded and fresh size mixed.

J A MESDUN L OPT EX T IL ES.COM

|

215

WA L L

Viscosity refers to the mixture and thickness of the adhesive as it is mixed and/or applied. It is just as important as, if not more important, than the adhesive itself. It generally does not take a lot of adhesive to secure a wall covering to the wall. On the other hand, too much adhesive can contribute to staining and could cause slight shrinkage because of the extra length of time it takes the wall covering to dry out, or for the moisture to dissipate from the adhesive. Therefore, with powdered or granulated pastes it is essential to follow the mixing ratios as specified on the product instructions.

Paste falls into two categories: 1. Powdered/granulated 2. Tub paste (premixed). Often a thick consistency, using an electric drill is a perfect way to ensure it is stirred adequately.

Powdered /granulated paste: • Mostly water and with some as high as 98%, leaving little solid content.

• These products are high in water content and low in tack.

• They allow a lot of water to be absorbed into the paper causing expansion, curling and lifting edges. If the product is hung too soon after pasting, peaking joins or expansion bubbles will occur.

Tub paste: • This is a premixed product which is very low in water content and very high in tack.

It provides the installer with good movement on the wall and can be used for both conventional wallpaper or for non woven paste-the-wall product.

• This adhesive takes away any guesswork in mixing paste as it is premixed and has P.V.A. as

its base. Due to its high tack it has a low water content in comparison to traditional pastes.

pasting system is used it is activated by dipping the wallpaper into water. You would refer to the label on the roll for further instructions.

• Tub paste can be either rolled or brushed directly onto the wall surface or onto the back of many conventional wall coverings.

In almost all cases, manufacturers do not hesitate to replace damaged or faulty wall coverings. However, they do have an issue with reimbursing labour costs especially if it was possible to identify the problem either prior to the job or following the installation of the first roll hung.

• Used correctly tub paste will give adequate movement and slip with plenty of time to position the wall covering.

• It is essential to read the instructions on the tub and follow the instructions of the manufacturer.

• If the instructions on the wall covering state that a tub paste be used then don’t use packaged paste as there will be too much water content and this will have an adverse effect on the wall covering/installation.

• If tub paste is recommended by the wall covering manufacturer it means that this particular wall covering cannot stand too much moisture. The soak relax time on the label will be approximately 3 to 5 minutes unlike other products that can have a soak/relax time of up to 8 to 12 minutes.

INSTALLERS CHECK LIST While manufacturers have quality control procedures in place which are followed, sometimes product that is less than perfect ends up in the customer’s hands. For this reason it is essential the installer inspect each roll for any possible defects prior to installing the wall covering.

Prepasted/Ready pasted: • When wallpaper already has the paste applied to the backing, it is known as prepasted/readypasted. When this type of

2 16

NOTE: It is the total responsibility of the tradesperson to fully check the wall covering for any and all defects such as shading, white edge, trimming etc. before the installation starts.

The following should be checked before starting: Have the correct number of rolls been received?

Check the direction of the design.

NOTE: The shorter the specified soak/relax time the less moisture the product can stand.

• By using a granulated paste on a product that requires a tub paste, the expansion of that product can continue for up to 20/25 minutes. This makes it very difficult to achieve a good installation.

Hang 2-3 lengths, allow time to dry and inspect the finish.

Get the client to approve before proceeding. Do not continue to install flawed material if there is a fault found.

CATHERINE MARTIN BY MOKUM / CABARET WALLPAPER

PASTE/ADHESIVES

COVERIN GS

Check labelling to see if the paper needs to be “reverse hung”.

•

Make sure that all rolls for each separate area have the same pattern and batch numbers.

•

Check for physical damage.

•

Check for any difference in colour and shade, especially with darker backgrounds.

•

It is the sole responsibility of the installer to check the dye batch and ‘shade’ of the rolls before starting the installation.

J A MESDUN L OPT EX T IL ES.COM

|

217

WA L L

Installation guide INSTALLING PAPER BASED PASTE-THE-PAPER WALL COVERINGS PASTE THE PAPER

JAMES DUNLOP / SHADE WALLPAPER

Some of these ranges hang as a normal wallpaper should, but there are those that refuse to act the way one would expect, by curling and seams that just refuse to lie flat against the wall.

x

Please find below procedures to help ensure installation of these products is more successful: • Some of the problem may not only be the wall covering but also the lack of good wall surface preparation. Always make sure that all surfaces are prepared correctly, are dry, sound, well sanded, dusted, sized and sealed with a pigmented sealer where necessary.

• It would be beneficial to coat the walls with a good even coat of Latex size (ready-mixed size).

This type of size is the only one that has the ability to re-wet or

COVERIN GS

re-activate when wall coverings are hung over it. The re-activating of the size ensures a good bonding at the seam area, which helps them lie flat against the wall and also gives good movement during the installation.

lengths with a wet towel to contain the moisture and stop the lengths from drying out. This will give the installer plenty of time to work so there will be no need to rush.

• When the product has been relaxed and is hung with the latex size on the wall, reactivating or re-wetting will also help to set the seams and prevent edge curl.

If the edges do lift slightly do not use a seam roller. This will only add to the problem by forcing the paste away from the seam and onto the decorative face of the paper. Apply a small amount of vinyl-to-vinyl adhesive to the curled edge, lay flat and cover with a warm cloth.

• Allow enough time for the paper to relax. Product curling is caused because the base layer is paper; when wetted by the paste it absorbs moisture and must expand. All paper based products once wet will expand between 1% and 2% of their width. The top layer of the paper is solid vinyl and does not expand as quickly or at the same rate, hence the curl. Once the base or web has fully relaxed and the pressure has time to even up, the curl will disappear.

• After installing any wall covering always let the product dry naturally.

• To help eliminate the curl, after pasting and booking the paper, roll the sheet loosely like a newspaper. The rolling of the folded paper will hold the edges together and prevent the edges from drying out, thus reducing the chance of the seams lifting.

Leave the rolled sheet for about twice the length of time for relaxing that it says on the instructions. In summer when the dissipation or evaporation rate is high, cover the rolled

J A MESDUN L OPT EX T IL ES.COM

• Never add any form of heating to the room/area that has just been papered, as this will cause the drying wall covering to shrink and the seams/joins to open. The use of a dehumidifier can have the same effect, as it is designed to remove moisture from the air, so this will also force dry the wall covering.

|

219

W O V E N

SOAKING TIME/WET EXPANSION This is relevant to paper based products.

Soaking time is the time it takes for a wallpaper to fully expand and relax prior to hanging. Wet expansion is the amount the paper will expand during the soaking time. Any wall covering that has paper as its base will, when paste is applied, start to absorb the moisture from the paste causing the paper base to expand. This, depending on the product, can be between 1% and 2% of its width, during soaking time.

Once the adhesive has been applied, the paper is folded paste to paste, with a small fold at the bottom and a larger fold at the top. This is called ‘booking’.

The paper is then put aside to expand fully prior to hanging. The soaking time will be determined by the manufacturer and will be on the label around every roll of wallpaper.

Once the wall covering has expanded during its recommended relax time, it is now ready to be installed. Following the installation of the product the water in the adhesive will start to dissipate and dry away.

Excess adhesive underneath the wall covering during the installation will slow down the drying process. Generally this dissipation will take between 24 to 48 hours. However, it may take a week or more, depending on the thickness and amount of adhesive that has been applied, the porosity of the wall surface and the wall covering itself.

If the adhesive has lumps, providing these are soft and mushy, they will normally dry away. If the lumps are hard this means the adhesive has not been mixed properly and when the wall

covering dries these will show as lumps under the finished wall covering.

Many installers believe that when a wall covering does not stick properly they should automatically add more adhesive. This could in fact be the worst thing to do as too much moisture can cause other problems, especially to the seam area.

Extra adhesive applied to the seams means the seams will dry out last, possibly causing seam springing/opening during the drying process.

The term “adhesive volatile” refers to the rate at which the water evaporates from the adhesive once it has been applied.

During hot dry summer months, especially on new constructions, the adhesive volatile factor is high.

When the temperature is cooler and/or the humidity rate is high, the evaporation rate will be much slower.

If an installer re-applies a strip too many times during the initial alignment, failure may result. Each time a strip is removed the paste and moisture are reduced, either by evaporation or simply because the wall surface has absorbed the moisture from the adhesive. It may become necessary to reapply additional adhesive to compensate for the loss of moisture and adhesion. Otherwise, an adhesion failure will occur, even if the preparation of the surface has been carried out properly. This problem is more likely to occur with do-it-yourself paperhangers, because they often re-adjust a strip many times to obtain accurate placement.

While the adhesive is drying out (dissipating), the wall covering will contact tightly and virtually suck itself to the wall. During this process, all the adhesive wrinkles present during the installation will

2 2 0

WA L L

disappear. There is a tremendous amount of torque or tension that occurs between the wall covering and the wall during this drying out period. This is why it is so important to apply a good coat of size or sealer prior to installing the wall covering. Many failure's are due to the installer applying too much pressure to the material during the installation. This is especially true at the seam/join area. It is not necessary to use a “seam roller” to get the seams to lay flat. Too much pressure on the seam will force adhesive away from the seam area, which is the most critical area to have the proper amount of adhesion.

Never apply too much adhesive when pasting wall coverings. This will generate an excess amount of moisture which will retard the drying and could cause shrinkage problems during the drying stage, especially if the preparation has not been carried out correctly.

It is very difficult to salvage a poor installation. That is why all necessary preparation steps must be taken prior to beginning the job.

In some cases it is possible to rescue loose seams once the edges have dried by applying moisture with a small brush, allowing time for the wall covering to relax and expand then applying a small amount of “vinyl to vinyl” adhesive. Lay the paper flat and cover with a warm cloth, do not rub or use a seam roller.

PASTING MACHINES When using a pasting machine, be very careful not to pull the paper through the machine too fast.

Problems can arise when a lack of paste is applied onto the backing of the paper, causing dry patches and not enough moisture to attain maximum expansion and stick ability.

Always use the paste/adhesive recommended by the wall covering manufacturer and do not overthin the paste. If the correct ratio cannot be achieved with the pasting machine, revert back to the old paste brush and paste bucket method.

There has to be enough paste applied to the back of the paper to both relax the paper and adhere it successfully to the wall. Don’t rush.

Some premium papers may require more time to achieve a good job.

James Dunlop tub paste is often a thick consistency. It is normal for the thickness to vary from tub to tub. It can be diluted up to 10% without compromising the paste’s effectiveness.

An electric drill piece stirrer makes mixing the paste simple.

NOTE: It is the consistency of the adhesive not the amount that is important.

INSTALLING NON WOVEN PASTE-THE-WALL WALL COVERINGS This new and advanced product means we now have a wall covering that does not have paper as its base or web. Its base is synthetic-polyester and is termed a fleece or non woven base. This product can be layered with a vinyl layer and be printed and embossed just like a conventional paper based product.

The product has additional advantages for the installer: • The adhesive can be applied directly to the wall.

COVERIN GS

• It does not open at the seams during the drying process.

are usually heavily embossed. Use either acrylic or oil based paint.

• There is no need to cut lengths.

Use straight from the roll.

Follow the preparation for the wall surface that is appropriate and set out in this chapter.

• No waiting.

Both the paper and non woven products must be allowed to dry thoroughly before applying any paint.

The ability to move the product on the wall will be determined by the consistency of the adhesive used.

The recommended adhesive is tub paste. Roll or brush the adhesive directly to the wall, don’t overload the wall with excess paste, roll the adhesive out to an even layer. Only paste enough wall area for 3 or 4 lengths of product. Any more and the adhesive could start to dry out.

This drying period may be up to 7 days or more, especially if using an acrylic paint, which is water thinned.

If painted too soon after installation the paper/non woven will wrinkle and pull away at the seams and could also cause expansion bubbles.

The only size recommended is granulated/powdered size or diluted tub paste.

It is recommended that the first coat of paint be an oil based pigmented sealer. This will allow the product to be painted in which ever finish is required, and will stop any staining from bleeding through to the surface.

Recommended preparation of wall surfaces prior to installation is the same for non-woven substrates as has been previously discussed in this chapter. However, as the base or web of this product is less dense than traditional paper based products, an oil based pigmented sealer must be a part of the preparation when using light colourways, as ghosting or show through will occur.

While this product is a great advancement in our industry, the product will react adversely if installers don’t follow the instructions: • Don’t paste the product, paste the wall.

• Don’t use a pasting machine.

• Don’t use a powdered paste.

This has too much water and can cause slight shrinkage at the seams during the drying process.

• Only use a tub paste.

• The wall covering does not require time to soak and relax.

PAINTABLE WALL COVERINGS

• It does not expand when it gets wet.

Most wall covering manufacturers produce a range of paintable paper or non woven wall coverings which

• It does not peak at the seams.

J A MESDUN L OPT EX T IL ES.COM

|

221

W O V E N

WA L L

Stripping wall coverings

COVERIN GS

WET REMOVABLE:

6. Try not to damage the substrate.

Wall covering that can be removed from its support on which it was hung by soaking it with water or a proprietary stripping agent or by steaming it and then scraping off the soaked material. Do not use liquid detergent – the residue can cause problems with adhesives.

7. Once all the paper has been removed allow the surface to dry completely.

8. Sand and dust.

9. Fill all imperfections with a sandable filler and allow to dry, sand smooth and dust. Sandable filler is one that when sanded turns to powder.

Always use a proprietary brand of wallpaper stripper. Do not use liquid detergent as the residue can cause problems with adhesion:

10. Dust entire surface to completely remove all dust particles.

11. For best results prior to installing new wall covering coat entire surface with a good even coat of latex size.

JAMES DUNLOP / EASTERN WINDS WALLPAPER

1. Remove as much of the paper as you can, dry.

x

2. Apply water with wallpaper stripper added with brush, sponge, or garden sprayer.

DRY PEELABLE: Wall covering from which the decorative or protective surface can be removed manually from its backing in a dry state substantially in one piece. The backing remains on the support on which it was hung.

STRIPPABLE: Wall covering that can be removed manually in a dry state, substantially in one piece, by pulling away from the wall on which it was hung.

12. If stripped walls show any signs of darkening or water stains then after filling and sanding etc, coat the entire surface with a coat of oil based pigmented sealer. Sand with 80g sandpaper, dust and size.

NOTE: A steamer could also be used. Take extreme care, the steam is very hot, don’t leave the steam pad on the surface of the wall for too long or the steam will penetrate into the wall surface and could lift the paper off the plasterboard.

3. Start working from the skirtings and work up.

4. Let the water do the work, don’t rush.

5. Give the water time to soak into the old paper.

J A MESDUN L OPT EX T IL ES.COM

|

223

W O V E N

•

•

Issues that can arise in wall coverings

If the installer is slow in applying the paste, they should apply the paste to the centre of the strip first then quickly paste the edges. This technique will help prevent the edges from curling too fast before it can be booked-folded together.

Opening seams/joins – relevant only to paper based products: •

Once the material has been booked, it should be loosely rolled in a manner similar to a rolled newspaper, being careful to avoid creasing the folds. This technique will not only hold the edges together, but will also prevent the edges from drying out during the soaking or relaxing process.

These occur when the seams / joins of the wall covering spring or open during the drying process. This can be as little as part of one millimetre and up to two millimetres.

•

There are many reasons for seams to spring or open during the drying process of the wall covering. All wall coverings that have paper as their base/ web will expand and relax when wetted, but during the drying process will rely very heavily on the preparation of the substrate to have been carried out correctly to hold the wall covering in place, not allowing the product to move or open.

Peaking seams/joins - relevant only to paper based products:

Edge curl during installation generally due to improper surface preparation, incorrect soaking time and/or the wrong adhesive being used:

•

•

•

•

The main reason seams /joins peak during the installation is the product being hung too soon after pasting. In this case the two sheets of paper are both still expanding and are forced together, hence peaking at the joins.

The easiest remedy is to remove the length of paper from the wall and allow it to expand correctly before replacing it to the wall.

If the installer was to push the edges together too hard, peaking will also occur.

Curling seams/joins – relevant only to paper based products: •

•

•

Edge curl immediately following the application of the paste - this is caused by the backing paper or web of the wall covering expanding faster than the front.

It is important for the installer to book the strip - fold paste to paste immediately following the pasting process.

•

•

WA L L

Make sure the surface is properly sealed, sanded, dusted and sized and that the appropriate adhesive is being used.

Excessive moisture may cause edges to curl or allow the adhesive to penetrate the backing of the wall covering causing staining to the decorative surface. Too much moisture stops adhesion at the seams which may cause the installer to use a seam roller which will only compound the problem.

If a seam/join curls and will not lay down during installation, do not apply more paste to the area as this will compound the problem by adding more moisture, further delaying the drying of the seam.

Once dried, the curling can be rectified with a small amount of vinyl-to-vinyl adhesive.

2 2 4

Opening seams/joins can occur by the installer: •

Not sanding with the correct grit sandpaper, or not sanding at all.

•

Not sanding hard enough to give an adequate key.

•

Not dusting the entire surface, to remove all dust particles completely.

•

Not using a sealer and or size to seal off porosity of the wall surface.

•

Stretching the product, during the installation.

•

Force drying the product, either by putting a heater or a dehumidifier in the room, or by the heat of the sun coming into the room during or even after installation.

•

Using the incorrect paste.

•

Applying the paste too thinly.

•

Incorrectly using a seam roller.

All these factors do have a bearing on whether the seams will or will not open during the drying process. To prevent the seams from opening, make sure that all the

•

Lapped seams/joins – relevant only to vinyl wall coverings including non woven: •

When it is necessary to overlap vinyl over vinyl, a special adhesive must be used.

•

They contain special resins which permit a strong bond between the layers of the vinyl.

•

This adhesive should be used in all corners and anywhere where vinyl laps vinyl.

CAUTION: When using vinyl-to-vinyl adhesive, be sure to wash off any adhesive that is on the decorative face of the wall covering using a wet cloth, then towel dry. This is vital because once the adhesive dries it will turn shiny on the face of the wall covering and is impossible to remove.

Bubbles – There are several reasons why bubbles may form in wall coverings during and following the installation: •

Extreme porosity of the substrate/wall surface is a major culprit – surface preparation is critical. In some cases an oil based pigmented

Expansion bubbles – relevant only to paper based products:

sealer must be used to reduce and help eliminate the porosity. If a sealer is not used when the wall covering is installed, the porous areas on the wall will quickly absorb the moisture from the adhesive and cause an air pocket to form, which is revealed as a bubble.

recommended preparation steps are carried out, as per normal trade practice. There is no way to fix an installation that has dried with open seams.

NOTE: There is nothing in any wall covering, either imported or local, that will make or cause the seams to open.

COVERIN GS

•

Poor quality water-based paint can become soft and could also cause bubbles to form - On solid plaster or fibrous plaster walls, apply a coat of oil based pigmented sealer and then a coat of size to prevent the surface from gassing, causing bubbles.

Small bubbles can form around contaminants. All wall surfaces must be sanded, then dusted thoroughly prior to applying any sealer or size in order to remove all contaminants. Otherwise, these objects can be highlighted and telegraphed under the wall covering following the installation.

•

Bubbles can appear when installing over existing wallpaper that has not adhered completely to the wall surface.

The moisture in the adhesive on the new wall covering will cause loose areas to swell and expand in the existing wallpaper, causing bubbles to appear.

•

Bubbles may appear after a wall or area has been completed for an hour or two. This can happen when size was applied and if areas were missed. In this situation the drying wall covering sucks air through the substrate causing the bubbles. These can settle down if left alone.

J A MESDUN L OPT EX T IL ES.COM

|

•

As all paper based wall coverings require a water based adhesive system, it is important to allow the wall covering to soak and relax for a given time before starting the installation. Exact soaking time is on the instruction sheet, around every roll of wall covering. Failing this, the wall covering will continue to expand once it has been applied to the wall.

•

Expansion bubbles can be identified by being long and narrow, they will show in the centre 1/3rd of the sheet, they cannot be brushed out, the only way to get rid of them is to remove the sheet from the wall and allow it to relax for the given length of time before returning to the wall.

•

Expansion bubbles can only be caused by the wall covering being installed too soon after being pasted and not given enough time to relax before hanging.

225

W O V E N

WHITE EDGE:

Sometimes patterns will not match from roll to roll, this is mostly because the rolls were incorrectly trimmed, usually at the factory.

•

The most common problems associated with edge trimming are: •

Over trimming.

•

Under trimming.

•

Scalloped trimming.

Over trimming: The result of too much pattern being trimmed away. When an excess amount of material has been trimmed away, there is no way to compensate for the missing pattern.

If it is noticeable at a glance or is unacceptable to the client, the installer should stop and return the wall covering to the supplier.

•

If a dark background wall covering is to be hung, it is wise for the installer to colour the ends of the rolls before unrolling the roll.

•

Some installers use water based felt pens, some use food colouring, others chalk or pastels, to colour the ends of the product before it is installed, as it is almost impossible to colour the white edge when the product is on the wall.

Under trimming: The complete opposite to over trimming. Not enough of the selvedge edge has been trimmed away, resulting in a slight double image forming at the seam. This excess can be trimmed off on the work table using a straight edge and trimmer or return the product to the supplier.

Scalloped trimming: The result of the trimmers at the factory moving back and forth as the wall covering is passing through. This results in the seam weaving in and out when they are supposed to be cut perfectly straight. Not only does this make the pattern hard to match, but it is almost impossible to butt the seams.

Stop and return the rolls to the supplier.

•

It is the responsibility of the installer to colour the ends of the rolls of wall covering before hanging.

•

If an adhesive contaminates the decorative surface and is allowed to dry, some inks will flake off the surface of the wall covering, leaving ugly white marks. The installer must take care to keep all adhesive off the surface both during and after installation.

•

The installer must be careful to wash all adhesive off the wall covering as they go, don’t wait until the end of the job.

•

In the unfortunate event that paste is allowed to dry on the surface, it may possibly be removed by brushing off using a soft brush. If this is not successful, try removing the paste using a soft sponge and a mixture of 5 parts warm water to 1 part ammonia.

•

Do not over wet; too much of the solution in the seam area can break down the paste behind the wall covering and cause the seam to lift.

NOTE: This problem should be identified by the installer by the time the first roll is hung.

•

Paste on seams/joins on decorative surface of the product:

When using the ammonia solution, try it on a scrap of the wall covering before using it on the wall.

•

In almost every case, ink flaking is a direct result of the decorative surface having been contaminated with adhesive residue that has been allowed to dry on the surface of the wall covering. This could take up to six months to become apparent.

•

•

• NOTE: The installer should identify all of these problems within the first roll hung and should stop. The remaining product should be returned to the supplier.

A common problem, especially evident when installing dark coloured background wall coverings, as the edges show white when butted together. The white edge problem will show as soon as the first two sheets are butted together, they do not have to dry first.

the edge to curl away from the wall surface.

It is essential that installers avoid paste touching the decorative surface of wall coverings.

An installer must always avoid applying too much pressure to the seam area immediately following the application of the wall covering.

The use of a seam roller can cause excess adhesive to be forced out through the seam/join, therefore contaminating the decorative surface. Using a seam roller may also push the adhesive away from the seam, causing

2 2 6

•

Wash each strip with clean water to remove excess adhesive as you go. When installing wall coverings with a glossy surface, the wall covering should be gently towel dried immediately following the rinsing procedure to remove all residue adhesive.

COVERIN GS

SHADING: Shading of the wall covering is normally the fault of the manufacturer’s printing process.

EDGE SHADE: This is where there is a colour variation from one side of the sheet to the other.

JAMES DUNLOP / EMBELLISH WALLPAPER

TRIMMING ERRORS:

WA L L

With all-over plain designs and some textural type designs, the technique of reverse hanging can be applied. This involves reversing every other strip to match up the shading variation. In a perfect world this would work every time, but in reality, sometimes it does not happen. It is up to the installer to make the call, to carry on or replace the product.

SHADE, ROLL TO ROLL: There is a colour variation between rolls of the same batch/ lot number. When this is found the product should not be installed, but taken back to the supplier for replacement.

BUMPS AND RIDGES:

OUT OF SQUARE:

UNEVEN EMBOSS:

•

•

There are times when an installer is hanging a wallpaper perfectly plumb, however the pattern/design will run uphill or downhill as the installation continues.

•

Check first that the ceiling line, chair rail, corners, window and door architraves are in fact straight and level.

•

Very few structures are perfectly plumb and level, therefore it is likely that all patterns will need some adjustment from the installer.

•

In structures where it is obvious that the ceiling line, chair rail, door and window architraves and other obstacles are not straight and true, it is advisable to avoid installing pattern wallpapers that might accentuate the problem.

The embossment of the wall covering is deeper on one side than the other. This will give the effect of a shade variation. When one stands directly opposite a seam/ join and cannot see any colour variation, but when looking along the wall into the light one can see a light dark effect this is uneven emboss. This type of emboss problem should be seen by the installer when they hang one initial roll and the product replaced.

NOTE: It is the responsibility of the installer to shade the paper prior to commencing the installation and not continue if shading is discovered.

•

•

•

Bumps and ridges are a direct result of poor wall surface preparation. In some cases it would be advisable to apply lining paper to provide the good surface required for the particular wall covering. Hang the Lining Paper horizontally.

Lining paper can help soften any existing lumps and bumps, but will not eliminate them completely.

While the wall covering is in the drying process it will literally suck itself to the wall surface, so any imperfections under the paper will be telegraphed through to the decorative face of the wall covering.

Bumps and ridges under the wall covering are not a problem of the wall covering rather the wall preparation.

J A MESDUN L OPT EX T IL ES.COM

|

227

W O V E N

•

When installed properly, a wall covering that has been soaked and relaxed will not shrink back to its original state once it is on the wall. In order to make an accurate comparison from one strip to another, each strip must be allowed to expand for the same length of time. Once they are aligned, they should match perfectly, unless there is a problem with the trimming.

•

When installing a wall covering where the top of the sheet is matching perfectly but the pattern doesn’t match at the bottom, this is not the fault of the product. If the product was at fault, then the pattern would not match anywhere, top or bottom.

•

If a pattern matches in the top, but mismatches at the bottom, the wall covering has been stretched during the installation, or the wall surface is bowed or not straight.

•

•

There are times when an installer will install two strips of wall covering that have been soaked and relaxed for the same period of time, but they still don’t match. In this case the problem could be the product has a trimming fault, or it is possible that the wall covering has been overworked or overstretched during the installation process.

This can be avoided by the installer not brushing downwards too hard.

With extra long lengths, the installer should fold the paper in a concertina fold which is draped over a part roll of wallpaper. Folding and holding long lengths of wall covering in this way will reduce the stretch caused by the natural weight of the paper

being suspended for an excessive amount of time.

•

It is not recommended to try and match a wet strip against one that has completely dried. If the job cannot be finished in one period of time do not stop in the middle of the wall. Always stop in a corner so that next day the job can be restarted at this point. If there is any mismatch of the pattern it will be hidden by the natural shadow in the corner.

generally happen over a period of time and would be less evident the further away from the light source it became. It’s often not identified until a picture or mirror is removed from the wall and, due to having been shielded from the light, the paper demonstrates its original colour.

•

The colours most susceptible to fading are the paler shades such as yellow and pinks, and not as would be expected, the darker shades, such as rich blue, deep greens etc. This is because the paler shades have only a limited amount of colour pigment in them. The darker colours have a high concentration that affords better protection.

•

However, it should be understood, that like anything that contains natural pigments, they are not totally lightfast.

Wallpapers will eventually fade to some degree, regardless of the type and location.

COLOUR FADING: •

The most common cause of complaint, with reference to wallpapers fading, is ultraviolet light (UV).

•

In the majority of cases, the ‘washed out’ look of the colour is due to the paper’s subjection to strong sunlight.

•

It can be a particular problem where a room faces due south, where a lot of sunlight can flood in. The fading would

2 2 8

CATHERINE MARTIN BY MOKUM / ANTIQUE LACE WALLPAPER

PATTERN MISMATCHING:

J A MESDUN L OPT EX T IL ES.COM

|

x

W O V E N

WASHABLE:

Commercial spot removers:

Wall coverings which are exactly that - washable. The surface of this wall covering will withstand occasional sponging with a mild detergent and water. The vinyl coating on this type of wall covering is not able to withstand scrubbing to remove a stain or contaminant. These types of wall coverings are not suitable for high traffic areas.

•

Some may change the texture or alter the colour slightly, so always perform on a test patch first.

•

In all cases, grease splatters should be removed immediately.

•

Hot grease will penetrate even into solid vinyl. Where grease stains are noticeable, i.e. oil, crayon, lipstick etc. Applying talcum powder will absorb the grease from the surface of the wall coverings.

•

If this does not remove the stain, hold a piece of brown paper over the stain and apply a warm iron – this will absorb the grease.

•

Paintable wall coverings, when painted, should be cleaned, according to the paint manufacturers instructions.

SCRUBBABLE: Wall coverings can withstand more stains and dirt because of their makeup. For this reason they can be used in high traffic areas. Before installing the new product check the label around every roll for the degree of scrub-ability.

CATHERINE MARTIN BY MOKUM / SPLENDOUR WALLPAPER

Wall covering care and maintenance

2 3 0

There are many foreign materials that may be found on the decorative surface of wall coverings. These can range from adhesive residue to food, crayon, lipstick, fly spray etc.

Many wall coverings on the market are solid vinyl, designed to withstand the normal wear of dayto-day activities. However, some wall coverings are designed solely for their aesthetic value and need to be treated accordingly.

Customers should be aware of the different wall covering types and their relative durability as associated with dirt and other contaminants.

There are three different classifications of wall coverings with regard to cleaning durability: 1. Washable 2. Scrubbable 3. Spongeable

NOTE: Scrubbable wall coverings have changed over the years and in some instances are not as durable as they once were, not because of the vinyl layer but because of the ink system that some manufacturers use. Some ink systems have moved from a solvent based ink system to the water born ink system which doesn’t have the same strength. This makes some solid vinyl products less scrubable than they used to be.

MOULD:

SPONGEABLE: More delicate wall coverings primary purpose is to provide a decorative effect. However they may be able to be cleaned by using a dry cleaning sponge or dry cleaning eraser. Always test a small area first.

If you are not sure how to clean your wall covering, start with cold water and then try warm soapy water and a soft sponge. Take care not to overwet the surface of the paper.

Heavy physical scrubbing and abrasive cleaners should be avoided.

J A MESDUN L OPT EX T IL ES.COM

|

•

There is nothing present in any wall covering that will cause mould.

•

Whenever heat and moisture are found in combination, conditions are suitable for mould to grow.

•

Mould spores are organic and being airborne are continually in the air especially in humid areas and shaded areas subject to dampness.

•

It is good practice to wash the walls prior to an installation with an anti-mould solution, especially if a mould problem is suspected.

•

Mould spores are attracted to dampness and can be absorbed into the wall surface. The walls may dry out but the mould spores can lie dormant for years. Bring the dormant spores together with moisture and they will start to grow.

In modern homes, the lack of ventilation can contribute to mould growth.

23 1

GHOSTING/ SHOW-THROUGH:

1. As black spots, normally towards the ceiling line. If the mould is on fabric, furniture, or walls and the spots can be removed leaving no sign of discolouration it means that this mould is caused solely by a total lack of ventilation.

•

Most stains or staining of the decorative surface of a wall covering are transferred from the wall the product has been installed onto.

•

Discolouration can be caused by a number of contaminants such as oil, old yellowed plaster board, or sunburnt plaster board, old stained wallpaper that has not been stripped, or water soluble stains.

2. The surface of the wall covering will start to discolour with spots of various colours, i.e. grey, green, blue, black, pink etc. Any presence of these colours means that moisture is behind the wall covering and has revived the dormant mould spores on the wall surface.

When walls are stained with mould, remove the wall covering and wash the entire wall surface with an anti-mould solution.

When dry, coat the entire surface with an oil based pigmented sealer.

This will seal in all the spores and stop the colours from bleeding through the decorative surface of the new wall covering.

It takes a long time to eliminate a mould problem once it has formed underneath a wall covering. For this reason, an installer must take certain precautions to avoid the problem prior to installing wall coverings in the first place.

•

•

•

Here are some recommendations: 1. Wash all suspect walls with an anti-mould solution prior to installing any wall covering. This will kill any live mould spores left on the wall.

2. Stop any dampness from coming into the room and you will stop the mould. Good ventilation can stop a lot of mould problems.

3. Ensure the installers equipment is mould spore free. Mould can be introduced by an installer with contaminated equipment, such as paste brushes, pasting machine, buckets etc and these can be transferred to the new wall covering.

•

•

All contaminated surfaces can, when wet, transfer the stain through the web or backing paper to the decorative surface of the wall covering during the drying process.

Any stains that can be transmitted through the backing paper of the wall covering should be identified by the installer before starting installation.

Old wallpaper can, over the years, absorb dirt and grease, and when wetted by the adhesive from the new wall covering can be transmitted through the paper backing to the decorative face of the new wall covering, showing as a brown or dark patch.

Plasterboard or dry wall is susceptible to yellowing or sunburn. This is caused when plaster board has been installed and there has been no covering on it at all for some time.

The sunlight burns the fibres of the paper face and slowly the plasterboard darkens to the point where two problems arise:

This results in a very heavy contrast between the dark brown of the plasterboard and the white plaster. Wall coverings are not designed to cover this degree of contrast. If a wall covering is installed over this surface, ghosting or showthrough will occur.

2. If the sunburnt plaster board is not treated, and a new wall covering is applied, the moisture from the adhesive will mix with the sunburn and produce a brown stain which will transmit through to the decorative face of the new wall covering.

WATER SOLUBLE STAINS: •

These can be identified by the plaster board showing lighter in an area. This area will have a thin dark brown line around the outer perimeter.

This will be transmitted as the above.

•

Good preparation can eliminate all problems regarding ghosting/show- through and water stains.

•

To identify if a stain has been transferred from the wall surface of the wallpaper look at the seams of the wallpaper.

If the stain runs across the seam this proves that it is not a wall covering problem.

Manufacturers cannot make wall coverings with matching stains.

•

To eliminate all forms of ghosting and show-through/ bleeding, coat the walls with an oil based pigmented sealer.

Once dry, sand with 80 grit sandpaper, dust, and size before installing new wall covering.

WALLPAPER ADORNED WITH DECORATIVE BEADS: •

It is normal that beads will come loose during the application process.

•

It is normal also that loose beads will be found inside the wrapped rolls of wallpaper.

•

Apply paste to only one width of the wallpaper at a time, this allows no extra paste for the beads to adhere too.

•

Ensure the paste bucket is kept well away from the decorating area so that excess beads can not fall in.

•

If you do find beads have come in contact with wet paste, pull the paper back and remove the bead, before proceeding.

JAMES DUNLOP / RISE WALLPAPER

Mould will manifest itself in two ways:

JAMES DUNLOP / RISE WALLPAPER

W O V E N

1. The paper face of the plasterboard gets darker and darker but the plaster stopping between the sheets stays white.

2 3 2

J A MESDUN L OPT EX T IL ES.COM

|

23 3

Joins - opening

Joins - peeking

WA L L

Joins - lifting

Discoloration on surface

Discolorations showing from behind paper

Paper lifting away from the surface

Paper lifting at ceiling and skirting

Paper lifting where lapped

Lumps showing through paper

White edges

Bubbles - Long and narrow

Bubbles - pear shaped

Paste the wall - seams opening

Dark marks on seam edge

Beads adhering to underneath of paper

Completed installation shows stripshading

Pattern on paper not matching

W O V E N

A quick reference to the possible cause of some issues arising

COVERIN GS

CLEANING

Scrubbable

Lack of sanding Incorrect grit of sandpaper

Washable

Sponge

HANGING – PASTING INSTRUCTIONS

Surface not dusted Mis-pasting Incorrect paste used Lumpy paste Tub paste not used No sealer Incorrect sealer ie. Too shiny or greasy No paste or too thin Incorrect soaking/relax time Paper hung too soon after pasting Incorrect wall preparation Paper stretched during hanging Mould Artificial drying Incorrect smoothing action Faulty trim Vinyl to vinyl adhesive not used

International wall covering symbols

Ready pasted

REVERSE HANG: A technique for installing wallpaper in which every other strip is hung upside down. This ensures that the lighter and/ or darker edges of the textured wallpapers come together to minimise shading.

The pattern is not intended to be matched at adjacent lengths. Can be called “random match”.

HALF DROP:

More than one drop hung at a time and/or tub of paste left in range of falling beads

Every other strip of wallpaper that is installed has the same pattern sequence at the ceiling line. A drop match creates a diagonal pattern sequence.

Colour variation from one side of the sheet to the other Installer has not checked the effect after hanging one roll

Free match

Half drop

Straight match

Free match hang horizontal

REMOVAL

STRAIGHT MATCH:

Paste left on the surface

Uneven embossment of wall covering

Reverse hang alternative lengths

FREE MATCH:

Incorrect filler or not dry when papered

No size or not enough

Paste the wall

HANGING – PATTERN MATCHING

Every strip of wallpaper that is installed has the same pattern sequence at the ceiling line.

Straight match creates a horizontal pattern sequence.

Drying too fast

Paste the paper

Dry peelable

Strippable

Wet removable

LIGHT FASTNESS

The wall is bowed or uneven The paper has not been reverse hung

2 3 4

Good light fastness

J A MESDUN L OPT EX T IL ES.COM

Moderate light fastness

|

23 5