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Photos of A.S. Création Tapeten AG production at the Wiehl-Bomig site.

WALLPAPER ADVICE

 
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Wall surface analysis

What characteristics must the wall surface have?

For successful wallpapering the wall surface must be dry, firm, evenly absorbent, clean and smooth. Lightly coloured wallpapers need a uniform white background. Therefore, the colour of the surface needs to be adapted accordingly.

Damp Surfaces

A damp wall surface is not suitable for wallpapering or any other form of coating. Mildew quickly forms on damp wall surfaces and can damage a building's fabric.
Attempting to wallpaper a damp surface will result in the seams lifting and poor adhesion, particularly in the seam areas.

 

How do I find out if the surface is damp and what can I do about it?
Analysis Steps to be taken
  • Carry out a foil test
    (If condensation forms under the foil, the wall is too damp)
  • Moisture Meter (Determines exact degree of residual damp)
  • Remove the cause
  • Leave wall surface to dry
  • Heat and ventilate if necessary
  • Test again


Load-Bearing Capacity

Detachment of the wall surface (plaster, emulsion paint, chalky abrasion) means that adhesion of the wallpaper is not guaranteed. Seams or whole lengths can come away from the wall surface and ruin the overall uniform appearance.

 

How do I find out if the load-bearing capacity is compromised and what can I do about it?
Analysis Steps to be taken
  • Scratch or pressure test
    (If the surface is damaged by pressure, it is too soft.)
  • Adhesive tape test (If old paint sticks to the tape, it must be removed)
  • Remove loose and unstable areas
  • Chalky or sandy plaster surfaces can be pre-treated with a wallpaper primer (e.g. Metylan wallpaper primer for old plaster)

 

Sintered Layers

Sintered layers are accumulations of binding agent on the surface of the wall that prevent firm adhesion of wallpapers or other wall coverings. The characteristic features of sintered layers are a gentle surface sheen and low absorbency.

How do I find out if the wall surface has sintered layers?
Analysis Steps to be taken
  • Criss-cross the surface with a sharp implement and sprinkle with water
    (Sintered layers may be present if the scratches turn dark)
  • Sintered layers must be mechanically removed by sanding

 

Absorbency

The absorbency of the wall surface is a crucial factor for the success of wallpapering. If a wall surface has very poor absorbency or cannot absorb any more moisture, it is not suitable for wallpapering as adhesion to the wall surface cannot be achieved. In the worst case scenario, it is probable that the strips of wallpaper will fall off.
It is also problematic if the wall surface is too absorbent. This can cause problems because the wallpaper paste is absorbed too quickly by the wall surface, creating an extremely high surface tension, which in turn may result in splitting of the seams.

 

How do I find out if the wall surface has too much or too little absorbency?
Analysis Steps to be taken
  • Sprinkle with water
    (If the water just rolls off, the surface has too little absorbency. If it is absorbed very quickly, it has too much)
  • Use of non-woven lining paper is recommended for use with non-absorbent surfaces
  • Lining paper should be used for surfaces with poor absorbency.
  • Walls with too much absorbency should be primed again


Rough Surfaces

Rough and dirty wall surfaces show through when wallpapering. As a result, the hung wallpaper will not produce a good result after decorating.

 

How do I find out if the wall surface is rough or not clean?
Analysis Steps to be taken
  • Shine a torch sideways along the wall to check for roughness and soiling
  • Smooth out rough surfaces with filler and then use non-woven lining paper, if required


Alkaline Surfaces

Alkaline wall surfaces such as new plaster or concrete are not suitable for papering with grass, bronze, or metallic wallpapers. With other wallpapers, blistering may occur in some cases; which manifest themselves as spots on the wallpaper.

 

How do I find out if the wall surface is alkaline?
Analysis Steps to be taken
  • Wet the surface with distilled water then use indicator paper to determine the pH value
    (If it is higher than 7.8, the surface is alkaline.)
  • Allow the surface to dry until it has reached a pH of 7
  • Alternatively, wash down the alkaline surface twice with a magnesium fluorosilicate solution followed by a clean water wash
  • Then apply non-woven lining.


Cracked Surfaces

Cracks in walls and ceilings can adversely affect wallpapering in a major way.

What can I do if there are cracks in the wall surface?
Type of Crack Steps to be taken
  • Hairline and fatigue cracks
    (Can be made visible by wetting of the surface.)
  • Shrinkage and joint cracks
    (extend across the entire plaster layer as far as the joints)
  • Static and expansion cracks
    (as a result of the building's construction)
  • Non-woven lining paper should be used to bridge hairline, fatigue, shrinkage and joint cracks.
  • Special measures are required to remedy static cracks.


Mildew

Mildew can develop anywhere where nutrients are present and moisture occurs.

What can I do if the wall surface has been affected by mildew?
Cause Steps to be taken
  • Room air too humid
    (The cause for mildew must be established and removed.)
  • Preventive measures, such as regular airing and well-controlled heating, leads to a reduction of humidity.


Efflorescence

White salt blisters on the surface of the plaster may occur as a result of moisture rising from a leaky damp course or masonry, or following water damage.

What can I do if there is efflorescence on the wall surface?
Cause Steps to be taken
  • Leaky masonry or water damage
  • Wallpapering should not be carried out until appropriate renovation measures have been completed

 

Detailed information about Surface Characteristics and Problems may be downloaded here.