Is this damp?

tonyh66

cyclonebri1 wrote: »

There is a very easy and effective way to check for damp.
Get hold of a piece of clear polythene about 12" square.
Wipe the wall with a dry cloth, then tape the poly to the wall ensuring all edges are sealed.

Check in the morning, any misting on the inside, and you have some form of damp.
Again, because it's easy to go off on the wrong track, it's far more likely to be penetrating damp for some reason than it is to be rising damp.
There are experts in this field that deny rising damp even exists, just something to bear in mind.

good advice, but I bet the experts aren't 'Damp Proofing Specialists'

aj9648

hi

just to answer a few of the questions....the door is fine and sealant is ok. also we bought the place a year ago and survey came back ok - although i know that means nothing

i had someone round today to have a look and according to him because i have outside walls rendered....these is a possibility the damp has been caused by this - moisture always getting through and thats causing this - i think

tonyh66

how old is the house? is it solid walls? if so the render could be the cause, If its cavity walls the render should not be the problem unless they have covered the weep holes with it.

cyclonebri1

Assuming it has solid walls it's more likely that render was applied to fix already damp walls, spelched bricks etc, rather than causing the problem itself.
Is the render painted?, if it isn't it may be enough to apply a water proofing coat although I have no experience of this working 100%, ie my experience shows it doesn't always work, plus you still have to get things dried out and the plaster sorted if blown and all traces of rot removed

aj9648

House is 1930's built but the damp bit is in the extension which was built 1985.

cyclonebri1

aj9648 wrote: »

House is 1930's built but the damp bit is in the extension which was built 1985.

Strange, that will have cavity walls, well it dam well should have.

It sounds as if something is either bridging the cavity, ie the ties are bridged or it's full of mortar rubble etc. You shouldn't have this issue in a modern build provided it was done correctly.
The other point is what is happening directly outside, blocked gutter, overflowing drain etc.

You really must determine if it's a cavity wall by measuring the thickness it will be around 10" in total inc plaster and render if none cavity and 2" or so thicker if a proper cavity construction.
Do this at a door or window reveal.