Advice on damp

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patcher

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Just looked at a job. Blown plaster under a window on exterior wall. Its finish on hardwall. Guessing since its hardwall it most of been done recently (out of interest how long has hardwall been the main stay?). Definitely a damp problem. Looked for tide mark on other walls but didn't see anything. So thought must be penetrating. Looked outside and there is a concrete path but up against the wall - looks like its created a bit of a swimming pool. Checked the guttering and it looked ok. Suggested cutting back concrete and filling will gravel? Then do the plastering?

Am interested to hear from those who know a bit about penetrating damp and are happy to share their fountain of knowledge.

Ta

Patcher. ;)
 
It sounds like its the window, has it been fitted recently? is it sealed? has it got a cill? with a drip underneath?
 
theres a load written about damp in the newbie section...
shouldnt use hardwall to patch up a damp wall anyway...
agree with flynny though, prolly the window, it usually is...
 
it may just be a cold wall and when warm inside condensation is creating the damp. try an air brick and replaster with nhl lime render so it breaths
 
you didn't say whether new house or old,as flynny said could be cill, are the windows wood/plastic,is the cill on the inside damp/wet.
 
these jobs are difficult to diagnose...
to give one possible cause from many others...
the window may have been fitted with the back edge over a cavity of some description...
that would cause the weight of the window to push the back edge of the cill down, thereby forcing the front edge up...
that would in turn cause water not to run off the front edge of the cill, but off the sides (ends) and into the brickwork where its gonna soak in...
its probably not gonna be that but ive seen it happen on an upstairs window and the downstairs one was damp... took me a while to figure that one out but once corrected, end of problem...
 
Chris W said:
these jobs are difficult to diagnose...
to give one possible cause from many others...
the window may have been fitted with the back edge over a cavity of some description...
that would cause the weight of the window to push the back edge of the cill down, thereby forcing the front edge up...
that would in turn cause water not to run off the front edge of the cill, but off the sides (ends) and into the brickwork where its gonna soak in...
its probably not gonna be that but ive seen it happen on an upstairs window and the downstairs one was damp... took me a while to figure that one out but once corrected, end of problem...
Click to expand...
thats an intresting one Chris could of spent many an hour scratching your head on that one glad you figured it out.
 
i only got it cos i used to fit em!
'window fitters' these days can cause more problems than they solve... box sash rip outs can be a nightmare...
 
Cheers for the advice fellas.

Just a add a bit more detail is a solid natural stone wall so no cavity. There is no sign of tide mark and salt deposits.

The window is hardwood frame which looked like in good nick - but I didn't check the silicon seal around the window - (i will have another look at seals) but there was no evidence of pooling on the inside seal.

Its one of these houses that has been injected and and gypsum/cement used - this seems to be a bit of a mind field at the moment???

The ventilation in the room shouldn't be too bad 'cos there is a chimney and to the best of my knowledge it aint blocked.

I know its a good suggestion but don't wanna go down the lime plaster route cos then you have to go down the lime paint route and he wants to wallpaper and paint.

I take the point about hardwall and damp(water) - the same goes for carlite. But the hardwall (not put on by me) seems fine (not mushy) so don't really wanna hack it off unnecessarily.

Think that my plan is gonna be check window seals/potential probs, cut back concrete and fill will gravel, hack off loose finish and reskim. Is SBR more appropriate then PVA? Would black jack be the belt and braces approach (inconjuction with trying to solve underlying damp cause) or will this just push damp (if it still remains) further up wall and therefore a waste of time?

Thanks again for the two brains is better than one help.
 
Your really need to find the damp problem. If these no salt or tide marks and the plaster is in good nick. What makes you say its damp.

Also if a damp company has injected it it will probably be under some sort of guaranty, so get them back to have a look.
Just because its loose don't always mean its damp could just have been put on badly.
 
its natural stone no cavity so imo very prone to penatrating damp/salts so if its not window ect. I would either lime it (best option i would think) or thoraseal it then s+c it, ive sin people sbr then s+c with no problems 2 years on but i would not recommended that. Personaly i cant believe someones put hardwall on it :o :o :o
 
if its had 'injection mortar' treatment, that might not have worked in the area youre at... its hit and miss at the best of times, they reckon electro osmosis can work better on 'solid' (not really, ill bet the core is full of rubble in places) stone... but if theres no mildew (as per render systems - condensation) then it could be penetrating damp oo rising damp... hacking the concrete back outside and installing a french drain is always a good idea, did it down a foot or so and blackjack the wall, backfill with 14mil clean gravel or so..
internally hacking it off and tanking the area would be a good idea, then render it or better still give it a scratch coat, tank it, then float coat it...
come up a metre high just in case, should be fine then...
if you dont wanna tank it then an sbr slurry painted on in two coats will be almost as good...
 
if its a solid wall then remove all the cement render and re do with nhl lime render even if this doesnt cure the problem 100% then there will be another cause but you cant expect a solid wall to breath with s and c on ;)
 
technically no but it wont do too much damage and isnt the idea to cure the problem? im sure there isnt an unlimited budget..
what about limelite? wouldnt that be just as good?
 
Chris W said:
technically no but it wont do too much damage and isnt the idea to cure the problem? im sure there isnt an unlimited budget..
what about limelite? wouldnt that be just as good?
Click to expand...

I have never used limelite but if no cement in it then it should be ok
 
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