damp solid 9" wall, what to apply under plasterboard

rolysatch

New Member
hi

i'm not a plasterer but after a bit of advice if possible. my mum has an old house 1901 that the top attic room has a really damp front wall. the damp reader was reading upto 35 in places and the internal render has all blown. the walls are 9" solid brick, and when i hacked off some of the render to expose the internal brick the mortar joints are reading 50 on the damp meter and the yellow stock bricks about 30.

The roof is in decent shape so i'm guessing the damp is penetrating straight through the wall. the only trouble is on the outside of this wall is some original fancy 3d plasterwork of flowers etc, so that can't be touched, its also on the 3rd storey which make it difficult to add another coat of paint.

she hasn't got much money so i was going to try and sort it for her as she wanmts to sell up and move. my plan was to hack the old internal render off and paint something on the wall and then glue some plasterboard with some waterproof adhesive and dryline it.

my question is what would be best to paint on the bare brick? i have some tanking slurry left over from when i damproofed my garage a few years back. would that be sufficient? or would that and then maybe some dampseal damproofing paint on top of the tanking slurry.

do you reckon that would be sufficient? and what would you reckon would be best as an adhesive to hold the plasterboard in place but be damproof to hold it off the wall? i did use that expanding sticky foam for some insulated plasterboard on my own place which worked well rather than dot and dab but not sur3e if that would act as an extra damp membrane,

any advice appreciated, thanks in advance
 

rolysatch

New Member
wasting your time on inside the issues at roof level cracked slate dripping gutter or some thing on them lines/photos might help
hi thanks for the reply, no the roof is definately sound, verges above the damp are sound, valley's were a bit blocked but have been cleared and valley lead is in good condition. the overhanging fascia above the damp is all in upvc and sound. which is why i was thinking that the damp is penetrating through the 9" solid wall. it's worse in some places than others - it's within the red lines on one of the attached photos..

the damp is behind the decorative plaster flower mural thing mainly, the pebble dash below was redone about 5 years ago and all the damp seems to be mainly behind the mural thing. i've attached some photos from google street view - not the best quality - to give you an idea as i don't live there.
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rolysatch

New Member
Condensation
yeah it would be a possibility normally, but as she lives on her own now - and why she wants to get this sorted so she can move - she doesn't have the heating on up there. i've run a dehumidifier and it returns as soon as you turn it off.

i'm going to rip off all the internal plaster and see if there's anything obvious of where it's mainly coming from which might help to see the source of it externally. if i still can't find where its coming from i'll paint some tanking slurry on that i have left and then some of this maybe? https://www.ebay.co.uk/itm/DAMP-PROOF-PAINT-WHITE-5KG-DAMPSEAL-WALL-FLOOR-WATERPROOF-LIQUID-MEMBRANE-DPM/131155257373?epid=1437031394&hash=item1e8976681d:g:wysAAOSw8X9cl2xw&frcectupt=true and then dry line it and hope for the best and hope she sells it quick. unless there's a better product anyone can suggest?
 

ChrispyUK

Well-Known Member
hi

i'm not a plasterer but after a bit of advice if possible. my mum has an old house 1901 that the top attic room has a really damp front wall. the damp reader was reading upto 35 in places and the internal render has all blown. the walls are 9" solid brick, and when i hacked off some of the render to expose the internal brick the mortar joints are reading 50 on the damp meter and the yellow stock bricks about 30.

The roof is in decent shape so i'm guessing the damp is penetrating straight through the wall. the only trouble is on the outside of this wall is some original fancy 3d plasterwork of flowers etc, so that can't be touched, its also on the 3rd storey which make it difficult to add another coat of paint.

she hasn't got much money so i was going to try and sort it for her as she wanmts to sell up and move. my plan was to hack the old internal render off and paint something on the wall and then glue some plasterboard with some waterproof adhesive and dryline it.

my question is what would be best to paint on the bare brick? i have some tanking slurry left over from when i damproofed my garage a few years back. would that be sufficient? or would that and then maybe some dampseal damproofing paint on top of the tanking slurry.

do you reckon that would be sufficient? and what would you reckon would be best as an adhesive to hold the plasterboard in place but be damproof to hold it off the wall? i did use that expanding sticky foam for some insulated plasterboard on my own place which worked well rather than dot and dab but not sur3e if that would act as an extra damp membrane,

any advice appreciated, thanks in advance
Is there any ventilation in the room?

Does the window have a trickle vent?

Probably condensation due to insufficient insulation and poor ventilation.

Hack off, fit roofing lath to the wall and fit either insulated PB (all in one) or celotex(foil tape joins) and finish off with PB.
If you do this, don’t tank the walls with tanking slurry.
 

rolysatch

New Member
Is there any ventilation in the room?

Does the window have a trickle vent?

Probably condensation due to insufficient insulation and poor ventilation.

Hack off, fit roofing lath to the wall and fit either insulated PB (all in one) or celotex(foil tape joins) and finish off with PB.
If you do this, don’t tank the walls with tanking slurry.
thanks for the advice, i'll hack it off and give it a go. cheers
 
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