Leaving PVA before bonding

[Terence Slattery]

Hi All,

I'm aware when applying multi finish it's best to the leave the PVA mix 24 hours before applying a second coat before starting to skim, but I was wondering when you have a damaged wall with plaster which has crumbled away do you still need to leave the wall for 24 hours after applying the PVA mix or can you roll on your PVA mix and leave it a half hour and then start laying in your thistle bonding coat onto the PVA mix with the bonding sticking better than multi finish or is best practice always wait 24 hours after applying the PVA regardless of bonding or finishing?

Cheers,

 

[bobasd]

no need to wait 24hrs - just apply the first coat of 50:50 pva allow to dry, and then apply second coat.
begin plastering over when second coat of pva is tacky.
but post pics of any crumbling plaster - its no good trying to go over crumbling or blown plaster.
is there any damp involved?

 

[Terence Slattery]

I managed to remove the crumbling plaster in the damaged areas, for the majority of the wall it's okay but there were parts where it had blown and was crumbling so I ripped it away down to the laths. I was thinking of adding in a cut of some 9mm board if big enough and then taping the joins and covering with bonding coat to level and then skimming with multi finish over the top. I'll attach pictures of the walls including the most badly damaged one by the door.

 

[bobasd]

is the idea just to make good to the patches and skim over them or is it the plan to skim the whole wall?
after Pva you can fill the dints with anything to hand - you can buy small bags of repair plaster or Easy-fill to fill and skim.
make sure the laths are secure.

this might be an opportunity to move the light switch away from the architrave - say by 100mm to 125mm.

fwiw: do everything possible to keep your plaster coving in the good condition its in now.
there's been previous Damp Proofing in that room - make sure you are damp free.
the cant bay has been panelled - damp is often found behind bay panelling. do you have any musty or mushroom smells in the bay?