Newly plastered walls damp - why? And any remedy?

[kelfish]

I am currently renovating a house which was quite damp for various reasons (some rising, some through roof etc). The floor downstairs is concrete. A couple of the walls were back to brick due to the damp.

All walls were replastered with bonding underneath or skimmed including those that were not damp (these were skimmed). The plaster was taken to about 2 inches above floor level and left to dry in all rooms downstairs. Before skirting boards were put on bonding was used to fill the 2 inches below the plaster level to the concrete floor and a week or so after skirtings were put on.

Now, most walls downstairs are damp and not drying out (plaster was dry when painted).

Does anybody have any explanation for the dampness (including damp on walls that were not damp) and any way to stop the damp.

Thanks in advance for any help.

Kelfish

 

[stef99]

I'm not a builder but I would suspect that you have something in your walls which is letting water cross over from the outside wall.
I have heard of wall insulation doing this, but I cannot say for sure.

I assume the walls were left for a few days before you plastered? (there still may have been moisture trapped in the plaster (deeper than the surface)

 

[kelfish]

Hi Stef,

Most of the walls affected are internal walls (both sides are internal) and could not be affected by rainwater or any leaks.

 

[roy c]

It could be the bonding is sucking the damp out of the walls. Maybe you should of had it done with sand and cement then skimmed. Also it wasn't wise to fill the gap between skirting and concrete floor with the bonding,

 

[barnettgs]

Hi, you didn't say how old your house is and this link may not be related but it might help in any way so here it is: http://www.heritage-house.org/pages/managing-damp-in-old-buildings.html

 

[JohnD]

tell us how you have been ventilating the rooms since they were plastered, and for how long.

Were the bricks dry before plastering?