Repairing plaster for retiling

[TeaAndBiscuits]

Hi all,

knocked a load of tiles off a plastered wall and now want to retile.

The tiles took off the plaster skim and is down to various layers underneath.

My current plan is to knock off any remaining loose/weak plaster then use 'thistle one coat' to build this area back out flat and level to the untiled bit of wall next to it, then tile over top. As I understand it the one coat will be a suitable substrate to tile on.

My question is - how to prepare the surface for the one coat plaster? I mean PVA - what dilution, how many coats etc. Do I put one on, leave it to dry then another just before plastering or something like that?

TIA.

 

[Deleted member 292770]

i’d use multifinish. neat pva it all the day before.

 

[roughcaster]

NEVER PLASTER ON TO "DRY" PVA..
You can SEAL a surface with pva and let it dry, but when you're ready to plaster it, pva rhe area again, and then plaster onto it while rhe pva is still wet/tacky.
I always put RED food dye into my pva, that way, you can see exactly where you've been, and spot the bits you-ve missed.

 

[Deleted member 292770]

We’re all different. the pva is just to control suction . there’s plenty of key on that wall.
NEVER plaster on to wet pva. the plaster will slump down the wall and drag all over the place when your closing in.

 

[SpecialK]

I "skimmed" mine with cement based tile adhesive to flatten it off.

 

[Deleted member 292770]

NEVER PLASTER ON TO "DRY" PVA.

why not?

 

[darrington]

why not?

Read the instructions on every container.
When used as a primer or a sealer, the PVA must be allowed to dry.
If you're putting plaster onto a PREVIOUSLY PVA'd "sealed"wall, apply the new coat of PVA and plaster onto it while the PVA is still WET/TACKY.
You do it any way you want, but that's the instructions on the manufacturer's products, and that's the way I've always done it.

 

[darrington]

We’re all different. the pva is just to control suction . there’s plenty of key on that wall.
NEVER plaster on to wet pva. the plaster will slump down the wall and drag all over the place when your closing in.

That is NOT what the manufacturers say, and also, pva IS an adhesive, that can also be used as a sealer, again, read the instructions on the 5ltr containers,, it's says it all.

 

[Deleted member 292770]

WET

It’s not possible to plaster over wet pva . sorry.
Tacky fair enough , but tbh I’m not one for sitting around waiting for pva to partially dry .
I’ll come back tomorrow and skim over it. Given that pva is not waterproof and emulsifies when introduced to wet plaster i’ll keep doing it my way.

 

[Deleted member 292770]

That is NOT what the manufacturers say, and also, pva IS an adhesive.

They also do NOT say to plaster over WET pva.

 

[Deleted member 292770]

When used as a primer or a sealer, the PVA must be allowed to dry.

I advised the op to control the suction by SEALING it with pva. then skim over . there’s enough key on that wall there’s no need for an ADHESIVE.

 

[roughcaster]

They also do NOT say to plaster over WET pva.

When pva is used as a primer, it should dry, but when plastering onto it, it should be wet/tacky;,, (not dry).
Read the instructions.

 

[Deleted member 292770]

When pva is used as a primer, it should dry, but when plastering onto it, it should be wet/tacky;,, (not dry).
Read the instructions.

Stop saying wet please. You’re giving the inpression you haven’t got a clue.
One more time so the diy’ers don’t go doing something daft.
You cannot lay plaster over wet pva .

 

[roughcaster]

It’s not possible to plaster over wet pva . sorry.

So you're saying the manufacturers have got it wrong,!!

 

[darrington]

Stop saying wet please. You’re giving the inpression you haven’t got a clue.
One more time so the diy’ers don’t go doing something daft.
You cannot lay plaster over wet pva .