Primer on new plaster?

[RF Lighting]

Hello.

I have some tiling to do in a bathroom. The walls are bare plaster after the old tiles were removed.

The old tiles were really badly stuck on. You could pull six tiles off at a time with your fingers

Now is this just because a bad job was done originally, or do I need some sort of primer on the plaster to help the adhesive sitck?

If so, can you advise what sort of primer to use?

Thanks.

 

[tpt]

it was probably tiled when it was new plaster and this sucks the moisture out of the adhesive. Get yourself some quality self priming adhesive such as granfix multifix or (i believe) bal do one too.

If in doubt prime with an acrylic or sbr primer - not pva and then tile but stay away from the diy adhesives.

 

[RF Lighting]

Thanks for that.

Any thoughts on dunlop adhesive?

My local builders warehouse sells it and it comes in tubs identicle to bal

 

[Maxsys]

Depends what size your tiles are you cannot use tubbed adhesive if the tiles are too big, and they may be too heavy for the plaster

 

[RF Lighting]

The tiles are about 12" x 9" ceramic.

Will tubbed adhesive be ok or do I really need to use a powdered one?

 

[Richard C]

Do you know the tile weight?

I would always use powder adhesive on that size tile, tub may take an age to set & sometimes never does. You must acrylic prime when using cement based adhesive over gypsum plaster or plasterboard.

 

[RF Lighting]

Do you mean the physical weight of a single tile? I can go weigh one and let you know if thats what you mean.

The plaster looks to be gypsum based. It's grey in colour on top of browning.

Will any tiling place have acrylic primer?

Thanks.

By the way I did some floor tiling a few years ago with help from here and it's still as good as new. No cracked or loose tiles.

 

[Richard C]

Do you mean the physical weight of a single tile? I can go weigh one and let you know if thats what you mean.

Yes weigh a tile (but it might tell you on the box); plaster in good condition will only support a maximum of 20 kg/sqm & that includes > 4kg/sqm for the addy & grout. If your tiles weigh in at more than 18 kg/sqm you have a problem.

Will any tiling place have acrylic primer?

Avoid the DIY sheds & get a quality trade primer; Topps will have it but they are a bit expensive for DIY sales.

 

[RF Lighting]

Right, I've had a look. Each box contains 12 tiles and says it will cover 1m²

Each tile weighs almost exactly 1kg so I make it 16kg per m² including adhesive etc. so I should be ok?

I'll have a look for some decent primer. Do I just paint it straight onto the plaster?

Thanks for the help so far

 

[Richard C]

Each tile weighs almost exactly 1kg so I make it 16kg per m² including adhesive etc. so I should be ok?

Yes should be OK as long as the skim is in good condition & still stuck to the base coat.

Do I just paint it straight onto the plaster?

Yes, usually neat but follow individual manufacturer instructions.