Tile backer advice please

[Gareth1]

Hi All,

I'm renovating my bathroom and tiling the bath / shower area in 12mm 30.5cm x 30.5cm marble tiles. The end wall will be fully tiled. Another two walls will be partially tiled (from the bath to a door on one side and a window on the other)

I've removed the old tiles which came off easily. The walls are plastered with a pink skim coat and then a thick (2 to 3 cm) layer grey of backing which I think is plaster (not sure). Two internal walls are lightweight concrete blocks and I believe the external wall will be concrete block too.

Here's my problem - I've read that a skimmed plaster wall can only support 20 kg/m2. To cover a square metre I'd need about 10 tiles which would weigh about 25 Kg. I think that, with adhesive and grout, It could be over 30Kg/m2 easily.

Some kind of waterproof tile backer seems to be a good solution. I've never used it before. Can someone recommend a product / system to me?

Do I remove the old plaster and fix the backer boards to the block wall behind and can I pack out the backer board somehow so the tiles are flush with the areas of wall which I'm not tiling?

Many thanks
Gareth

[Dave]

Marmox boards are a good one..

Click the PHG wetroom logo on the left... he sells them.

[Gareth1]

Thanks.

I've just been reading their fixing instructions. One thing that's occurred to me is that I'll never remove all of the plaster residue from the wall. Can I still put the boards up with adhesive (priming with SBR first maybe?) or would screwing it every 300mm be the best way?

[Dave]

You can yes...

[Dave]

Here you go... http://www.marmox.co.uk/uploads/prod...oductSheet.pdf

[Gareth1]

Thanks

The guide doesn't mention priming the wall or the boards themselves. Is that needed?

Would this be the right way to do it?

1. Remove plaster and clean wall as best I can
2. prime wall with SBR (if needed)
3. stick marmox boards up
4. prime boards with SBR (if needed)
5. fix marble tiles (light colour) with BAL natural stone adhesive
6. grout with BAL micromax

[Dave]

You need to prime the walls because you can stick the boards uo wu=ith cement based adhesive.. no need to prime the boards..

Leave adhesive to set and then screw/washer.. but if the walls are flat and simply using to hang the weight, then screw and washer as you go..


As for adhesive.. then that brand is about the most expensive out there.. mapei or weber equally as good imo..