Advice on thickness of plywood for tiling bathroom floor

[Bob Alger]

I am about to tile my bathroom floor with 40x40cm ceramic tiles and would appreciate advice on the thickness of plywood I need to put down as a base. I have seen 18mm quoted on this and other websites and straight on the boards with the right fixitive on others so I am confused!!

I live in a modern house with 20mm T&G flooring that is in reasonable condition. I am planning on putting the WC and new stone resin tray for the shower cubicle straight down on the tiles (with plumbers mate in between) but I don't want to get it wrong and be doing it all again in a years time because the tiles have cracked.

I am tending towards using 18mm but am concerned that this + tile and adhesive will need a ladder to climb over the step into the bathroom.

Thanks for your advice

Bob Alger

 

[Mudster]

12mm WBP will be fine, but fit the tray before you tile and then tile around it.

You'll need access to connect the waste anyhow.

Fit w/c afterwards.

 

[sanjayp]

I used 12mm for my bathroom and it seems fine. I wouldn't go any thinner though. Try and use as large sheets as possible and screw it down to the floor boards very well so there is no movement.

sanjay

 

[ro63rto]

I used 12mm too. Important to screw down every six inches and try to drive some through to joists below, making sure you don't hit any pipes. By securing it to the floorboards AND the joists you minimise the movement as much as possible. You will still need to use a suitable tile adhesive and flexible grout.

 

[JohnD]

Are we talking about the same thing? If you're laying a new floor, straight onto the joists, 18mm is normal. If you're putting a ply sheet onto an existing boarded floor, to level it and give you a nice surface, 12mm is plenty.

Personnally, knowing what old bathroom floors are like (usually chipboard softened by water spills) I chose to rip up the old and lay new 18mm WBP. So, no ladder required to climb up to the new floor level!

 

[Bylough]

Just to complicate the issue- have you thought of warming these beasties from underneef- or are you using a mat and exiting the barf at breakneck speed?