How to Prepare Walls for Wall Papering

Posted on: June 20th, 2019

How to Prepare Walls for Wall Papering

The key to hanging wallpaper successfully is preparation, planning, and using the right tools.

Read below for a few common issues and how to resolve them when preparing walls for wallpapering.

Plaster and Filler

Filler is used when small imperfections such as little dents and cracks need smoothing out. It is quick and simple; simply squash the filler in, leave slightly proud; then sand down flush and flat when dry.

Plaster is usually reserved for large holes and major wall damage that may need to be repaired.

It needs to be applied in thin even layers so that it dries strong and evenly. It will need to be built up to the required level. Plaster is not designed to be rubbed down like fillers. It needs to be applied using a trowel, smoothing flush and flat by hand-trowel.

The edges of the damaged plaster will be very dry, and unless you seal these edges first with a PVA/water solution, the water within the plaster mix will be too quickly absorbed by the existing plaster, it will be sucked out, preventing a uniform, slow drying and bonding between materials. In other word’s the plaster patch will become loose and fragile.

The sealing solution must be allowed to dry properly before applying the new plaster, usually 24 hours.

Repeat this dampening of the area again, just prior to plastering. There’s no need to wait for drying out with this application.


Flexible Filler

Over time, cracks can appear around doorframes, caused by natural movement and use. Skirting boards also move over time and can become detached from walls, check also those fitted on staircases. Movement will re-occur, so fill in with a flexible sealer to avoid cracking.


Mould and Fungus

Mould or fungus infection of walls can be treated with a simple fungicidal wash. More importantly, find out the cause! The most common cause for this condition is moisture resulting from poor ventilation.

When stripping old wallpaper from walls infected, try and ensure you do not transfer the fungal spores from the walls and old paper to the new wall covering, or surfaces that it will come into contact with.


Dampness and the Stabilisation of Walls

So now we have our wall all nicely filled and patched up. The surfaces have been sanded or trowelled flush and smooth. What now?

Well, If the rest of the wall (s) are painted, then chances are it has over time accumulated a layer/film of grease or grime. It’s a good idea at this point to give the wall a good sponge down using a solution of sugar soap and clean water and allow to dry overnight.

Where there are signs of staining, perhaps from previous dampness, then this should be treated with a damp sealant or oil-based primer solution. Where damp is still evident and active, sealing will not cure the problem! In this case you should seek the advice of a professional.


Sizing Walls

If you have plaster wall’s then sizing or sealing the walls is a good idea. Size is a glue-like substance that is painted or rolled onto the walls and has several benefits:

  • stops the wall from absorbing all the moisture out of the paste
  • makes walls slippery for longer
  • prevents wall paper shrinkage

The result?  An easier application process; patterns and edges can be lined up and moved into position easier. The size effectively acts as a barrier stopping the walls soaking up all the moisture and glue. This will make removing paper much easier and prevent damage to the plaster in future. It will also stop the wall paper shrinking and creating gaps between lengths.


A wall that is properly prepared and stabilised will be easier to work with and will have a much smoother appearance.

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