renovating plaster and tanking

rolysatch

New Member
hi

i'm not a plasterer but having a go at a job for my mum as she hasn't got a lot of money so needs must so any advice appreciated. she's got two attic bedrooms with damp from the chimney breasts in each rooms, i've done everything possible to rectifty potential causes but walls still damp and plaster shot in places. its an old house and i've hacked of the old plaster back to brick where needed and the plan was to use salt neautraliser, tanking slurry and then prime with sbr and plaster with renovating plaster (which i've managed to get a few bags from someone who had some left over). does that sound about right?

there's a section in the wall in both rooms where the chimey flue rises that has a void with just some wooden laths covering it. will renovating plaster be ok on that or is there anything special i need to do to the wood or should I replace it with eml or something?

my other question is - and this may be a bit of a dumb question to you lot - where i want the new plaster to meet up with the old, does the renovating plaster shrink back enough while drying to drop back enough for the skim coat? so that when i'm putting on the undercoat plaster i can put it on wet, flush with the old plaster? as this would be easier to judge for me or does the undercoat need to be applied 2-3mm below the old existing plaster?

thanks in advance
 

Cockney1

Well-Known Member
hi

i'm not a plasterer but having a go at a job for my mum as she hasn't got a lot of money so needs must so any advice appreciated. she's got two attic bedrooms with damp from the chimney breasts in each rooms, i've done everything possible to rectifty potential causes but walls still damp and plaster shot in places. its an old house and i've hacked of the old plaster back to brick where needed and the plan was to use salt neautraliser, tanking slurry and then prime with sbr and plaster with renovating plaster (which i've managed to get a few bags from someone who had some left over). does that sound about right?

there's a section in the wall in both rooms where the chimey flue rises that has a void with just some wooden laths covering it. will renovating plaster be ok on that or is there anything special i need to do to the wood or should I replace it with eml or something?

my other question is - and this may be a bit of a dumb question to you lot - where i want the new plaster to meet up with the old, does the renovating plaster shrink back enough while drying to drop back enough for the skim coat? so that when i'm putting on the undercoat plaster i can put it on wet, flush with the old plaster? as this would be easier to judge for me or does the undercoat need to be applied 2-3mm below the old existing plaster?

thanks in advance
Pics for the perverts please!
 

smoother09

Well-Known Member
Why don't you pay for the work done if she ain't got a lot of money it's your mum ffs! Pay for a plasterer for her!
 

rolysatch

New Member
Why don't you pay for the work done if she ain't got a lot of money it's your mum ffs! Pay for a plasterer for her!
Because I've just built an extension, apart from pitching the roof, on my own place and done a top job, so fancied having a crack at this myself.
 

Louis1

New Member
Sounds like you’ve got the right idea, but the damp issue has to be solved before you replaster even if your using renovating plaster. Did a damp chimney in an old house couple of months ago, source of the damp was the chimney was completely blocked with rubble and soot. Gave it all a good clean inside and replastered with renovating plaster. No sign of damp anymore been about 5 months….. p.s we had to repaint with a special kind of paint
 

FreeD

Private Member
Don't use tanking slurry...use a membrane...PB2 from Permaguard, then dry line and skim. Damp on chimney breasts can be condensation or salts attracting damp or penetrating. A membrane will sort all the issues and never see damp again.

I've done around 50 breasts and never seen damp again.
 

Brimstone

Well-Known Member
Sort the outisde first where the damp is coming from - cap off disused chimneys, rain cap on those in use, sort the flaunching, fix the flashings, repoint or render any crap brickwork, clean out the chimney so that it can dry out internally. Only then consider fixing anything inside, otherwise it'll be a waste time.
 
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