tiling on ply wood?

[andy-p-]

Can you tile on ply wood in a shower cubicle? The builders who done my loft conversion did this instead of plasterboarding then skimming which i thought was the right way to do things. At least you put plasterboard up. My tiler said its not good. Whats right?
Thanks

[ultimatehandyman]

You can do it, but tile backer board is better.

The problem with plywood is that it expands and contracts, tile backer board does not to the same degree.

It will probably be fine, lots of people tile onto ply!

[andy-p-]

thanks for that.
will they have to pva 1st?

[ultimatehandyman]

NO, definately not

It is external ply that has been used isn't it?

Check the tile adhesive, some specify that if you tile onto plywood you need to use a specific primer first

[Mudster]

If it's too late to replace it, then tank it with BAL WP1 tanking system or similar

[andy-p-]

its only normal ply he's used. I'll get him to take it off and put plasterboard up. It's only screwed up

[ultimatehandyman]

Make sure it is moisture resistant plasterboard- ie. tile backer board

[biggies2006]

dont listen to andy-p- advice, the benefit of backer board and ply is that youve got a good strong fixing for your shower, hand rails etc and shower door. Also if you ever wanted to replace your tiles, you would have to replace all the plasterboard too

[peteyweakstraw]

Depends on the thickness and condition of the subflooring plywood. It may be too thin and flex which can cause cracking in the tiles and grout. If only3/4" thick, you should install a layer of 3/8 hard board underlayment first. The hardboard should be sealed before spreading the thin set and tiles.