How to fix cracks in a very flat wall Ask your questions and find answers on many subjects relating to plastering and dry lining

[Marek22]

Hello,

I striped a lining paper on a very old plaster wall. The wall has a lot of small cracks maximum 1mm width. I had a look at internet and it seems the best way to fix these is to use mesh tape (or other type of tapes) and then use some joint mixture over it.

Now my question is how to do this and keep the wall flat. Currently the wall is very flat and smooth and I can imagine this would definitely create a little bump (the thickness of the mesh tape plus some cover on top of the wall surface). In order to keep the wall flat do I have to create a little ridge with width of the mesh tape? So when I apply the mesh tape it is in deed under the wall surface so it will not create a bump?

One more question is it really necessary to use the tape or is it ok to use the joint mixture? The house is really old the and the plaster wall is at least 20y old as well. Will it develop these cracks again or is it stable after so many years?

Sorry for a long post and I hope no one asked before as I was unable to find this question.

Thank you for any help!

[stoneyboy]

Hi marek22,
Don't use mesh or tape - you'll end up with a ridge and furrow wall. If you try using a filler the cracks will come back so your best option is to line the wall again using a fibreliner paper.
A more expensive option would be to have the wall skimmed.
Regards S

[Marek22]

Hello thank you for your answer!

Do you think all of the cracks will appear? Or just some of them and they can be fixed again.

With the skimming option I read that if you apply on a plaster that is moving/cracking even the skim layer will crack in the same way as the base for the skim cracks.

I would really like to avoid lining paper :D

[stoneyboy]

Hi marek22,
If you fill the cracks will they reappear? - very likely. The only way to test this is to fill, make good and see what happens.
The skim option would have to include taping all large cracks or using sheet reinforcing mesh.
Regards S