Tiling on wall that's lost plaster finishing coat

[tcarnell]

Hi all,

I'm working on our bathroom and want to remove the old tiles which are only in certain areas of the room (around the basin and bath) and then tile the complete room with new larger tiles.
Where I've removed the tiles some of them have also taken off small areas of the finishing coat of plaster underneath, revealing the undercoat plaster below.

Do you think it allowable to tile over these areas, or should I skim them over with patching plaster first?

I've PVA'ed the areas in question to stabilise the plaster and seal it.

Thanks in advance,
Tony.

 

[Robbie uk]

Might be better to run a bit off easyfill over the areas that have come off, doesnt have to be super smooth, a least it will be all one level.

 

[joe-90]

Just tile over it. Complete all over tiles is very dated though.

 

[Richard C]

I've PVA'ed the areas in question to stabilise the plaster and seal it.

No, no, no; why does everyone insist on using PVA to prime a tile base. I use loads of it all the time when plastering but never, ever when tiling, especially wet areas; your tiles probably won’t stick very well initially &, as standard PVA is water soluble, they may well fall off again later if moisture gets in.

You need to rough fill the areas where the plaster is missing but be careful what you use; if it’s just the finish skim that’s come away, PVA the base & use Multifinish or you can use one coat or even powder tile adhesive, especially on deeper areas. Base coat plaster (Bonding etc) is not really suitable but for filling smaller holes it won’t matter too much; not sure Easyfill is suitable for tiling over so check. If the raw plaster areas are large enough to give suction problems for the adhesive, prime with an SBR based sealer, not PVA. If your using large/heavy tiles, you need a cement powder adhesive, not pre-mix tub adhesive

 

[roughcaster]

I've PVA'ed the areas in question to stabilise the plaster and seal it.

I think we should put up a "sticky" Rich',, advising where and when NOT to use PVA.

 

[Richard C]

I've PVA'ed the areas in question to stabilise the plaster and seal it.

I think we should put up a "sticky" Rich',, advising where and when NOT to use PVA.

We seem to be going through a real spat of it over the last few weeks, perhaps the PVA marketing board is having a sales drive!

Whats surprising is that some contributors on other tiling forums actually seem to be recomending it.

 

[joe-90]

I used to use PVA 20 years ago before I found SBR. Never had a failure with either in all that time. All this talk about dire consequences is a load of cobblers.

 

[Richard C]

All this talk about dire consequences is a load of cobblers.

I know of many that would disagree with you & a few that have posted on this forum. Apart from slowing down initial adhesive set time, once it’s all gone off PVA will not be a problem long term in dry areas; it’s wet areas that can really give you grief. If moisture gets in for whatever reason, PVA will emulsify, the tiles will loose adhesion & can eventually drop off, it’s happened.

SBR sealers on the other hand are not water soluble & won’t give the same problems which is why they are so much better, if you need a primer/sealer in the 1st place.

 

[joe-90]

If your grout/tiles are in such bad shape you need a re-tile anyway.