1st Job: Plasterboard vs Plywood vs Tile Backing Board

[Aspesim]

Project Cloakroom!!! (2nd Thread).

I have realised the plasterboard I’m due to tile, about half way along one wall (wall B) the next plasterboard is not levelled with the preceding one, therefore by the end of the wall there is about 10mm difference when I put a 6’ spirit level across it. There are also other issue like brown paper showing where the outer paper came away with the adhesive.

We have seen some tiles which we both like and are suitable for floors and walls. It is our intention to lay the floor in a brick pattern and repeat this on one wall (wall A), however due to the size of the wall/floor tiles 600 x 300mm we have been advised to replace the plasterboard with plywood due to the weight.

I didn’t realise how many types of plywood there were so what kind of ply would you recommended, thickness, soft or hardwood?

Because of the above issues with wall B I know it will need replacing but I’m not sure with what...
Plywood or Plasterboard (square edge or tapered)? The tiles on these walls are ceramic and are 330 x 250mm

Is Aqua board and tile backing board the same?
Can I use Tile backing board on all walls?
What thicknesses do I need?

I have far too many questions running around in my head so please bear with me. If you can answer any or all of my questions it’ll be greatly appreciated.

Other info approx size of the cloakroom is 850mm (wall A & C) 1900mm (wall B & D) Height 2100mm
Drywall on breeze block (wall B & C) Drywall on thermal block (wall A & D)
All pipe work is to be chased into walls!!

Regards
Simon

[Bri]

Hi Simon, don't use ply is my first response! You might have mentioned it in the post but just to clarify, the existing plasterboard is dot and dabbed onto the walls (dry lined)? If so remove and replace with plasterboard in the same fashion, the tile size you have chosen will not be too heavy for this. Cement board is a better option for holding more weight but not neccessary in your case and also as its a cloakroom can I assume there won't be any wet areas such as a shower? Are you tiling the whole room from floor to ceiling?

[Aspesim]

Hi Brian

Yes, I'm tiling floor to ceiling.

[Aspesim]

Hi Brian

There wil be no wet area's and I am tiling floor to ceiling.

[Bri]

Hi Brian

There wil be no wet area's and I am tiling floor to ceiling.

Then just replace your plasterboard like for like, tile straight to the bare boards, don't skim them as this will reduce the load capacity. Just double check the weight per square meter of your 600x300 tiles. Unskimmed plasterboard can take 32kg per square metre (don't forget to include adhesive and grout to the weight of the tiles, about 4kg per m2). If it exceeds this then go for cement boards on this wall.

[Aspesim]

Then is cement board aka Tile Backer Board?

[Bri]

Then is cement board aka Tile Backer Board?

Yeah there are a couple of varieties, Hardibacker is the one I use.

[Aspesim]

Thanks

I've seen Hardibacker online, what size would I need 6 or 12mm and how do you fix? To batten?

[Bri]

Thanks

I've seen Hardibacker online, what size would I need 6 or 12mm and how do you fix? To batten?

Either screw directly through it into the wall or put it on batons as you say. I'd be tempted to go for the 12mm, the 6mm will have a bit too much flex in it. If you go down the batten route, make sure there are plenty to attach the boards to, to give them ample support.