Do I glue this under shower tray?

[datadiyer]

Hi all,
Could someone please advise me if it would be better to D4 glue along the top of the 4"x2" frame to lay the 12mm marine ply on, or to just screw the ply on?
It's the base for a shower tray it is.
Many thanks in advance.

 

[Madrab]

Just screw it down, 150mm spacing. If anything though, I'd use a thicker piece of ply if it's not supported fully at the front edge.

 

[datadiyer]

Just screw it down, 150mm spacing. If anything though, I'd use a thicker piece of ply if it's not supported fully at the front edge.

Thanks again Rob, it will be supported at the front edge. Some 4"x2" I can unscrew and remove temporarily if a disaster leak occurs, hope won't come to that tho!

 

[Madrab]

The trick with your plinth top is it needs to be fully supported so there is no deflection at all, any deflection in the top means potential movement in the tray, movement in the tray means the risk that the waterproof seal can be compromised.

If I can be totally honest with you though, thinnest piece of ply/OSB3 board I normally use for a plinth top is 18mm.

 

[datadiyer]

The trick with your plinth top is it needs to be fully supported so there is no deflection at all, any deflection in the top means potential movement in the tray, movement in the tray means the risk that the waterproof seal can be compromised.

If I can be totally honest with you though, thinnest piece of ply/OSB3 board I normally use for a plinth top is 18mm.

Yes, in hindsight, I wish I went for 18mm. I have a 9 or a 12mm structural ply I could add under it .That would be better do you reckon?

 

[Madrab]

Yes, put your 9mm under it, are you going to tank the plinth/wet area?

 

[datadiyer]

Yes, put your 9mm under it, are you going to tank the plinth/wet area?

I've SBR'D the existing marine ply (including edges), I will also do same to the extra 9mm. Yes, I have a tanking kit for shower area, I didn't think that you tank the underlying ply also?