Tiling advice onto skim

greggp_2

I am soon to be tiling my ensuite using 198mm x 298 mm (5mm thick) porcelain tiles.

I have removed existing tiles and the adhesive – these came off very easily! It has left behind skim plaster and still intact – this plaster was done in 1992 and still looks in good shape.
Just wanted some advice on types of adhesive recommended to tile straight onto the existing skim and wether I will need to prime etc.

Any advice greatly appreciated

Thanks in advance.

Leif

It should already be primed. The primer acts to seal the surface, so it does not suck the moisture out of the adhesive before it has had a chance to soak into the plaster surface. The primer will give the plaster a sort of plastic satin finish. If the tiles came off easily, then it is possible it was not primed. I know nothing about adhesives!

muddyl

Just use a bathroom/shower adhesive, no need to prime.
It was always believed you had to prime, but new research shows not. (Tiles would stick to priming agent and not the wall)
If its in a bathroom, when combing on the adhesive, make the "lines" go verticle, prevents pooling of water should any get through in future.

David-PrestigeTilesKent

Firstly, remove all lose plaster and brush down the wall.
re-seal the wall area with a slightly watered down pva bond (to prevent the dry plaster pulling the moisture out of the adhesive)
Then grab yourself a powdered adhesive, mix little and often (slow setting if your diy)
Powdered addy will be best for porcy tiles and check the load bearing of your wall vs. the weight of the tiles.

tpt

The tiles dropping off so easy is a classic sign that the old tiling was done either too soon after plastering or that it wasnt primed - this sucks the adhesive dry too quickly.

All good advice from david- he obviously knows his stuff. the only bit i wouldnt agree with is the pva advice. pva has been used for years but most adhesive manufacturers explicitly warn not to use it these days as a lot of adhesives are polymer modified. Switch to acryclic primer.

One thing you may want to have a look at is granfix multifix, this is a self priming tubbed adhesive. Davids advice about using a powdered adhesive is right - especially if your over 300x300, but at that size you'll be fine with a good quality tubbed addy thats suitable for porcelain.

David - i'd change your username if i were you or you'll end up getting reported as spam all the time...

Leif

tpt wrote: »

The tiles dropping off so easy is a classic sign that the old tiling was done either too soon after plastering or that it wasnt primed - this sucks the adhesive dry too quickly.

And that is the reason all the tiles had to be removed from my newly tiled bathroom. Plastered Wednesday, tiled Friday, no primer. Tiles came off with almost no effort, especially from the top of the wall above the bath area. It was potentially unsafe.

greggp_2

tpt wrote: »

The tiles dropping off so easy is a classic sign that the old tiling was done either too soon after plastering or that it wasnt primed - this sucks the adhesive dry too quickly.

All good advice from david- he obviously knows his stuff. the only bit i wouldnt agree with is the pva advice. pva has been used for years but most adhesive manufacturers explicitly warn not to use it these days as a lot of adhesives are polymer modified. Switch to acryclic primer.

One thing you may want to have a look at is granfix multifix, this is a self priming tubbed adhesive. Davids advice about using a powdered adhesive is right - especially if your over 300x300, but at that size you'll be fine with a good quality tubbed addy thats suitable for porcelain.

David - i'd change your username if i were you or you'll end up getting reported as spam all the time...

Anyone give any guidance on how much adhesive thickness I should apply to the skim before fixing tiles?

Oldsoak

Use a 6mm notched trowel, then comb the adhesive at a 45 degree angle (only if you are sure that he walls are flat). Press the tiles on and give them a slight twist to bed them, then straighten and apply the spacers you have chosen. Never butt the tiles against each other as any movement will either pop them or crack them.
Good luck.

Tucker

I think I probably learned the hard way with bathroom tiles.

I ended up using Bal tile primer after a few mistakes.

In fact the end conclusion for me was Bal products were far and way the best and seemed to very well respected within the professional trade. IT's not cheap stuff but it was the dogs dangly bits and on a DIY job, try and do it right and do it once, because you'll regret scrimping on few quid later for what it's worth.

tpt

tucker - absolutely right. stay away from the diy stuff. go for bal or granfix, these are two well respected trade adhesives that are easily found.

greggp_2

Thanks for the input guys.

Need a bit more guidance if possible please.

Took a look at the walls at the weekend and they are quite a bit out of square so I am looking at the best way of tiling upwards. I am using 300mm high x 200mm tiles wide and plan to use 3 tiles high.

I have a back wall where WC and sink are to be located and will therefore tile this wall and the 2 returning walls (forming a C-shape) I am going to use a 3 row tile height (300mm high each) giving me an 900mm overall height and probably come back 3 tiles on the returning walls (200mm wide each) giving me a 600mm splash back area on these walls.

problem I got is that tiling upwards - the first 2 tiles high are not a problem as the wall is relatively square but as soon as I want to put the 3rd tile on the wall slopes out of square.

Do I put more adhesive on the first 2 tiles upwards and use less on the 3rd tile – I am worried that if I use too much on the first 2 tiles it will suck the tile back in when setting leaving me with a headache for installing the 3rd height tile.

Hope this makes sense. I wanted to try and do a sketch to show my problem but not sure how you upload it on here.