Bath panel problem?

[PJ Tiling]

I'm doing a bath panel on request of customer, using 18mm ply I know its pretty thick and it might be a tad heavy but the customer wants what they want.

My question is......Ply has been primed, tiles on. Came back today to grout and silicone......only to find the ply has bowed!

[GirlRacerRed]

what tiles have you put on the ply PJ?

[PJ Tiling]

Nothing special just B & Q finest cermaic tiles with BAL white star addy

[GirlRacerRed]

what did you prime the ply with?

[PJ Tiling]

BAL SBR primer

[little ken]

if you can take the bath panel of screw and glue a piece of 3x2 on the back

[pjc]

throw it away and use plaster board or backer board as ply always will bow

[doug boardley]

as Pete (pjc)^^^ from me

[kilty55]

cement board for me

[PJ Tiling]

Cheers guy's i'll use some backerboard, It's a weird one tho why does ply warp? I thought I would be ok with 18mm?

[doug boardley]

Cheers guy's i'll use some backerboard, It's a weird one tho why does ply warp? I thought I would be ok with 18mm?

because most of it is cheap and nasty stuff these days

[Dave]

Cheers guy's i'll use some backerboard, It's a weird one tho why does ply warp? I thought I would be ok with 18mm?

because most of it is cheap and nasty stuff these days

And you used a dispersion adhesive which subjected it to moisture ingress overnight..

[pjc]

Yes Dave also if you tile ply both sides with rapid adhesive would need a fork lift to move it about but it would be equal laminates and more prone not to bow but ply is oribale stuff great in the wood burner lol