damp proofing

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irish_spread

irish_spread

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Hi lads. Hope someone can help me out here.

Ive done loads of rendering around bay windows over the years to cure rising/penetrating damp
and bridged damp courses but this one has me puzzled.
Years ago the owners removed the skirting and plastered to the floor with bonding. Obviously
this area became damp but the rest of the wall was ok. as she was selling the house i said u may aswell
re render the bay. I put a scratch coat of s+c with sika1 on, the following day a floating coat of s+c
with normal sika waterproofer, couple of days later skimmed it. 2 weeks later i go back to brush off
the efflorescence and find the skim is still black- occupied house with heating on!! The damp is now worse
than it ever was. Rang sika- they blame the sand,the cement, using multi, my belle mixer, application methods- everything but their product. Any ideas to the cause lads???? Thanks
 
bridged damp course and poss some penetrating. Problem is the 1st sika tech advice bloke said
sikas ordinary w/proofer would have done the job, 2nd one said it wouldnt. Got dampness now
where there was none before!!!
 
sika said that aswell but its damp everywhere i rendered and dry where i overskimmed. Did a small patch
in the kitchen (internal wall-4m2) rendered with one coat sika1 then skimmed- same problem. t he
house has the heating on and its def not condensation
 
its got to be the moisture coming out the render and skim, cant be anything else. how green was it when skimmed. the only thing to do is take off a small area of skim, see whats going on under it, if it looks damp, leave a week and see if it drys out. your looking at a mm a day for drying on damp walls.
 
simplybesty said:
its got to be the moisture coming out the render and skim, cant be anything else. how green was it when skimmed. the only thing to do is take off a small area of skim, see whats going on under it, if it looks damp, leave a week and see if it drys out. your looking at a mm a day for drying on damp walls.
Click to expand...

cheers simply, thats what i was thinking but some of its only 15mm and wet and one section is
about 40mm and dry (missing bricks). I cant work out wots causing it- only thing i can think of is did the sika get affected by frost while in the van but even then....
 
irish_spread said:
Hi lads. Hope someone can help me out here.

Ive done loads of rendering around bay windows over the years to cure rising/penetrating damp
and bridged damp courses but this one has me puzzled.
Years ago the owners removed the skirting and plastered to the floor with bonding. Obviously
this area became damp but the rest of the wall was ok. as she was selling the house i said u may aswell
re render the bay. I put a scratch coat of s+c with sika1 on, the following day a floating coat of s+c
with normal sika waterproofer, couple of days later skimmed it. 2 weeks later i go back to brush off
the efflorescence and find the skim is still black- occupied house with heating on!! The damp is now worse
than it ever was. Rang sika- they blame the sand,the cement, using multi, my belle mixer, application methods- everything but their product. Any ideas to the cause lads???? Thanks

did u go to the floor with the render if u did the the dampness in the wood would still creep up wall u always leave a gap at the bottom when ur plastering rooms with wooden floors
Click to expand...
 
no George, i didnt mate, stopped couple of inches short of the floor. But even if i had
the w/proofer should still work. This one really got me stumped
 
Sounds like because you have basically tanked it, that it is now condensating there is no where for any moisture to escape , and you said you went back to brush off the efflorescence which its self attracts moisture , any moisture in the air would of just been fed back into the finish via the salts, they may well of had the central heating on but if there is no air circulation and fresh air flowing through the rooms then any moisture will just remain in situ, have your clients tried ventilating the rooms? try this for a few days then see if there is any difference , if not , then as you said the sika may be at fault, so it's back to square one and start over again :(
 
warriorupnorth said:
Sounds like because you have basically tanked it, that it is now condensating there is no where for any moisture to escape , and you said you went back to brush off the efflorescence which its self attracts moisture , any moisture in the air would of just been fed back into the finish via the salts, they may well of had the central heating on but if there is no air circulation and fresh air flowing through the rooms then any moisture will just remain in situ, have your clients tried ventilating the rooms? try this for a few days then see if there is any difference , if not , then as you said the sika may be at fault, so it's back to square one and start over again :(
Click to expand...
agree with warrior on that
 
warriorupnorth said:
Sounds like because you have basically tanked it, that it is now condensating there is no where for any moisture to escape , and you said you went back to brush off the efflorescence which its self attracts moisture , any moisture in the air would of just been fed back into the finish via the salts, they may well of had the central heating on but if there is no air circulation and fresh air flowing through the rooms then any moisture will just remain in situ, have your clients tried ventilating the rooms? try this for a few days then see if there is any difference , if not , then as you said the sika may be at fault, so it's back to square one and start over again :(
Click to expand...

cheers warrior, u may have a point there. Gonna have to pop back 2 the job to do another bit of work anyway.
Thanks
 
flynnyman said:
sounds like condensation as warrior said and its usually black.
Click to expand...

Cheers Flynny, it deffo sounds like condensation but i overskimmed an area on the same wall which
has dried out ( have 2 admit the overskimmed bit was under a metre high but it is dry)
Its not condensation, think its either the sika has 'decayed' (used the same 'can' on a previous job
which was sucessful) or as simp said 1mm perday drying time. Its really pi55ing me off >:(
 
irish_spread said:
flynnyman said:
sounds like condensation as warrior said and its usually black.
Click to expand...

Cheers Flynny, it deffo sounds like condensation but i overskimmed an area on the same wall which
has dried out ( have 2 admit the overskimmed bit was under a metre high but it is dry)
Its not condensation, think its either the sika has 'decayed' (used the same 'can' on a previous job
which was sucessful) or as simp said 1mm perday drying time. Its really pi55ing me off >:(
Click to expand...

Out of interest was it asian sika you used? ;)
 
flynnyman said:
irish_spread said:
flynnyman said:
sounds like condensation as warrior said and its usually black.
Click to expand...

Cheers Flynny, it deffo sounds like condensation but i overskimmed an area on the same wall which
has dried out ( have 2 admit the overskimmed bit was under a metre high but it is dry)
Its not condensation, think its either the sika has 'decayed' (used the same 'can' on a previous job
which was sucessful) or as simp said 1mm perday drying time. Its really pi55ing me off >:(
Click to expand...

Out of interest was it asian sika you used? ;)
Click to expand...

its got black bean sauce in it so i suppose, yes it is ;)
 
I went back to a job that another team had done (properly) on closer inspection the old timber sash windows were letting in rainwater from above which was permeating through the wall. In this case the solution was to dig out the old external mortar from around the windows, fill with expanding foam for windows, then repoint. once this was done it was ok. have a squint at the bay windows outside. this wouldn't cause black fungal growth though....
 
spredz said:
I went back to a job that another team had done (properly) on closer inspection the old timber sash windows were letting in rainwater from above which was permeating through the wall. In this case the solution was to dig out the old external mortar from around the windows, fill with expanding foam for windows, then repoint. once this was done it was ok. have a squint at the bay windows outside. this wouldn't cause black fungal growth though....
Click to expand...

yep spredz have come across this in the past and ur dead right. However all of the wall around the wall around the window that i didnt hack off and re render (overskimmed it ;) ) has dried normally- less than 1m above ffl aswell.
will take some pics on me phone and try an put 'em on here 2morro (if i can)
Thanks everyone
 
go to photobuckets.co.uk or .com whichever it is, sign up (its free) loads your pics into that then it will give you sn IMG code, copy and paste that into the reply box on here and it should come up.
 
jesus :D are your pictures on your phone or camera? i can tell you how but it will take a while. might be easier for him to do it. just remember IMG code!
 
put a halogen light and it seems to be drying, loads of efflorescence tho.
One way flight to spain for irish_spread ;D
 
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