Damp

[Paulboy]

Hi guys,

Recently brought a house which has a very slight damp problem along the back wall. its is a 1960s ex council house with cavity walls and i believe has had cavity wall insulation. Up to about a meter high the wall has been very thinly rendered and a tyrolene type finish applied. The surveyor says this may be the cause of the damp problem(as there is no "bell Drip" but when i got a builder round he said not.(btw the surveyor said there was no damp in a roof part of a bay window when there definately is!)The back walls do feel cold to the touch where the is a patio door

So heres my questions....

Do i remove this rendering and have it redone.
Have the back wall damp proofed(once we have removed the kitchen)
Test the walls with a damp meter myself

I have read about cavity wall insulation bridging the gap and therefore allowing damp to spread from the outer to the inner walls. The is on this house a line of blue brick at the bottom so find it hard to believe that damp has come up through them.

Any help appreciated

 

[JohnD]

Rule out condensation first.

If you tightly tape a piece of clear polythene to the inside of the wall, you will see if water appears on the wall side or the room side.

See also our Wiki on Building, Condensation.

Look for any possibility of water falling on the outside, e.g. dripping gutters or leaking downpipes.

 

[Paulboy]

will do, there does appear to me be mold on the plaster at the back of the kitchen cupboards

 

[JohnD]

will do, there does appear to me be mold on the plaster at the back of the kitchen cupboards

This is typical of condensation (the exterior wall is cold, and the cupboard keeps it colder).

//wiki.diynot.com/building:condensation_in_houses