Applying Size to Freshly Plastered Walls

How to Clean Your CDs
31st January 2017

What is Size?

Size is a thinner kind of wallpaper paste, which can be bought from all good DIY stores. Just like wallpaper paste size is inexpensive, but what a difference it makes in the finished quality of the look at the end of your project. Simply follow the manufacturers instructions on how to mix and apply the size.

Applying Size

Applying size to a wall or ceiling prior to papering prevents wallpaper shrinkage. This avoids the gaps that can appear between the lengths that you have hung once the paste has dried.

On newly plastered walls the problem increases as freshly plastered walls and ceilings will suck paste out of the paper. This can be prevented if the plastered surfaces are sealed before doing anything with them.

The surfaces can be sealed using a solution made up of white matt paint and water.


  • Paint your size solution all over your newly plastered surface
  • The solution will dry very quickly on the new plaster. This happens because the plastered surfaces has sucked all the moisture out of your solution
  • Once dry, paint on another coat of the solution
  • Allow to dry overnight
  • Apply to the wall again and allow to dry overnight

Your newly plastered walls or ceilings are now prepared and ready for wallpaper/decorating.

Previously Papered or Painted Surfaces

On previously papered or painted surfaces, an application of size is required.

Once Dry:

  • Apply the paper as normal, butt the edges against each other.
  • Once dried, step back and admire you handy work - look no gaps!