Studding a shower enclosure - plasterboard or ply?

[Deansplit]

I posted a thread a short while back asking if standard plasterboard was Ok to use for a shower, when tiled over or should you 'always' Aqua panel/cement based board? The general view was AP although some suggested if the tiling's done properly with good waterproof grout then PB is fine. I've spoken to a few people who said they've used 9mm plywood. What's the view on this?

 

[Richard C]

I would never advise ply as a tile base on walls & using just 9mm is a joke; WBP ply will not de-laminate when wet but it’s still wood which is not dimensionally stable when subject to moisture. For anywhere outside the enclosure use 12.5mm MR plasterboard, except if fully plastering the wall then ordinary wall board will do. For wet areas inside enclosure or around bath, no question IMO, use 12.5mm waterproof tile backer board. If you use PB, tank it or it’s unlikely to go the distance.

Often misunderstood is that unless you use one the very expensive epoxy products, waterproof adhesive & grout is only waterproof in the sense it wont disintegrate when wet, it will still absorb water/moisture which is why it’s important the tile base in wet areas is waterproof & remains dimensionally stable if affected by moisture otherwise your tiles end up on the floor!

Take some time to read the tiling archive posts, it may just prevent you making some potentially expensive mistakes.