WBP / Exterior Plywood

kig · 15-05-2026 05:15PM #1

Just wondering whether there is a difference between WBP and exterior plywood.

I want to use it for a section of bathroom wall, to hang a shower seat, so needs to be stronger than plasterboard.

The Continental Op · 15-05-2026 10:59PM

Who knows? Should be different but very hard to know. WBP is only relates water proof glue, exterior ply should have waterproof glue and be made of wood that is suitable for exterior use.

In your application you could use cement board eg

https://www.mcmahons.ie/cemrock-cement-board-2400x1200x12mm-55071

https://www.chadwicks.ie/permabase-cement-board-2400-x-1200-x-12mm-32905.html

tabby aspreme · 16-05-2026 06:05AM

If you are going to use plywood give Woodworkers in Terenure a call, they stock several types of good quality plywood and will advise you

Lumen · 16-05-2026 06:14AM

I'm sure you know what you're doing, but shouldn't a shower seat be fixed to whatever is behind the wall surface (stud, block) rather that the surface itself?

In which case the strength of the ply/plasterboard/whatever isn't particularly important.

The problem with ply is that your fixing is going to be a channel for water ingress, going right in through all the layers and potentially rottingin the exact place where you need pull-out strength.

Bullocks · 23-05-2026 08:50PM

Will you be tiling the wall ? If you are it won't really make much difference. I've done a good few disabled bathrooms and prefer to put 9"×2" between the studs because it won't flex as much as the ply might and there is more for the bolts/screws for the seat to bite on .

Slab over it , tank it and then tile .

Don't forget to pop in grounds for grab rails aswell while you're at it

Mr321 · 23-05-2026 10:58PM

Marine trailer floor plywood is what you need.

WBP / Exterior Plywood

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