Help please, we had a chemical damp course put in 2 years ago and we keep getting a crack appearing about the level they knocked off the original plaster. The crack runs all around the downstairs walls they did. The damp course was not injected but brushed on?? any help or advice would be greatly appreciated. We've repaired the cracks at least 2 times and they still show up. We even had 2 wall's re skimmed with skrim tape over them and they still show up!!!
Cracks in plaster
- Thread starter dodgepot
- Start date
Sponsored Links
i do damp proofing/replastering and have not had this problem so i'm at a bit of a loss.
the paint on is called "tanking". the type i use is cement based so it expands/contracts with temp pretty much the same as bricks & plaster. after the brush on then i am required to render over the top. this i taper into the existing plaster so that when i put the finish on it tapers into a feather edge. once painted you have to look quite close to see any join.
all i can think of is that the tanking used was not cement based and maybe rendering was also not applied/tapered in.
i tend to use caulk to fill cracks as it remains flexible. dig out the crack using a saw blade to get a good bead in, then flatten with a flat scraper. then spray on diluted washing up liquid and hand blend over the surrounding plaster. try just 1 wall to start with.
if this does not work then i feel a strip of plaster at the joint needs removing and re rendering over the top of the tanking to produce a taper into the existing plaster. then follow with skim.
the paint on is called "tanking". the type i use is cement based so it expands/contracts with temp pretty much the same as bricks & plaster. after the brush on then i am required to render over the top. this i taper into the existing plaster so that when i put the finish on it tapers into a feather edge. once painted you have to look quite close to see any join.
all i can think of is that the tanking used was not cement based and maybe rendering was also not applied/tapered in.
i tend to use caulk to fill cracks as it remains flexible. dig out the crack using a saw blade to get a good bead in, then flatten with a flat scraper. then spray on diluted washing up liquid and hand blend over the surrounding plaster. try just 1 wall to start with.
if this does not work then i feel a strip of plaster at the joint needs removing and re rendering over the top of the tanking to produce a taper into the existing plaster. then follow with skim.
just a further thought. i use galvanised mesh if i'm plastering over wood as this is prone to cracking otherwise as wood expands at a different rate to brick.
you would need to remove the existing plaster, fix the mesh over the top with galv nails into mortar joints in the brickwork and then replaster over (screwfix 94846 is typ).
you would need to remove the existing plaster, fix the mesh over the top with galv nails into mortar joints in the brickwork and then replaster over (screwfix 94846 is typ).
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
