Will plaster stop damp

by Matthew gutridge
(England )

If I use muti finish plaster with pva would it stop damp coming though? Or any ideas would be great.

No it definitely wont stop the damp coming through. The only 2 options you have is to either stop the Damp coming through which is always the best option or make the wall breathable by using lime so that the damp can easily evaporate away and not be funnelled into one area.

Either way it is always good to try and identify the source of damp. A common problem in older houses:
In older houses (40years plus) sometimes the damp proof membrane of the floor (if there is one) may not be lapped into the wall and just butts up to it but not joining it. Therefore if plaster is applied all the way down to the floor it may be in contact with un-damproofed material and damp can rise up the wall. This can be avoided by cutting the plaster off about 1 inch up the wall to leave an air gap to be covered by skirting. If no skirting is present then a bitumen type paint should first be applied before plastering all the way down.

Also in some older houses the damp proof course can be higher than floor level - some Victorian houses have damp courses half way up skirting board, which was fine - as the skirting board was generally fixed before the wall was plastered. Then the plaster would be applied down to the top of skirting board, which would have an air gap behind. It is now common practice to plaster first and fix skirting boards after, hence when they have been renovated the damp course has been known to be bridged and damp problems start!

Also look for defective guttering, cables entering walls and high external ground levels that can easily rectify damp problems.



Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Backing Coat Questions & Answers.