by AB
(London)
I'm due to skim my dad's wall for him. He has removed the skirtings and took some of the wall with it so he's re boarded but not done It that well and there are gaps of up to 14mm including at a 90 degree corner with another wall. Would it be ok to scrim over a gap of this size. The scrim tape covers it no problem but it done know if I should pre fill (if so with what?) before skimming with multi finish as I've always had much smaller gaps. I really don't want to reboard but I also don't want cracking as I'll get the blame!
Answer
Firstly fill the gap with bonding coat and then apply scrim tape, if it doesn't stick properly then use a very thin smear of bonding coat to stick it. Push some more bonding coat through scrim and remove any excess, then apply another layer of scrim tape. If you have really big gaps then 3 or 4 layers of scrim tape combined with bonding coat plaster really will stop the cracks.
Then plaster with multi-finish as normal, however if before you get to plastering, the bonding coat has dried out - then damp down prior to plastering.
Paul