just laid down my 12mm plywood floor over chipboard substrate screwed at 150mm centres with non-threaded shank zinc plated screws. i'm waiting for my tuff2 tray to arrive but have a few queries before it does:

1. i lay the ply with 3mm expansion gaps between boards, when i cut out the tray area shall i leave expansion gaps between tray and boards or is it not necessary?

2. what screws shall i use to fix the tuff2 tray to the joists? how far shall i space screws? (tray is 820 x 1500mm and joists are spaced 400mm apart)

3. do i need to countersink screws that are fixing down tray? if so, do i fill them after with filler?

4. as i used 12mm plywood (due to step at door) do i need to use a de-coupling membrane on floor?

many thanks for any advice given

Hi roberto, I havent used the tuff2 wet tray system before but heres a link to there web site hope this helps. Wetroom level access shower tray formers for wood floor installation

What tiles are you using?
as yyou are creating a wet room you will need to use a tanking system to work with this tray. for walls and floor.
you could use the schutler kerdi for the walls and the schutler ditra for the floor this is a decoupler which i would prefer to use on the floor. or the durabase ci.
you can get these products from wetdecs who is a sponsor on here and will provide them at good prices. hope this helps steve...

The screw holes are marked on the trays.. and they are counter sunk in advance..

Abrade the surface of the tray with sand paper and then tank the whole lot with a suitable membrane.. makes a better job..

Originally Posted by roberto1490

just laid down my 12mm plywood floor over chipboard substrate screwed at 150mm centres with non-threaded shank zinc plated screws. i'm waiting for my tuff2 tray to arrive but have a few queries before it does:

1. i lay the ply with 3mm expansion gaps between boards, when i cut out the tray area shall i leave expansion gaps between tray and boards or is it not necessary? You will have a slight gap from cutting which you should fill will silicone or similar. Your floor tanking membrane will bridge this area so you will have a seal anyway

2. what screws shall i use to fix the tuff2 tray to the joists? how far shall i space screws? (tray is 820 x 1500mm and joists are spaced 400mm apart)
Tray is pre drilled if you find youy holes dont hit a joist you can drill

3. do i need to countersink screws that are fixing down tray? if so, do i fill them after with filler? The holes are already countersunk if you do drill then countersink yes

4. as i used 12mm plywood (due to step at door) do i need to use a de-coupling membrane on floor? You should use an uncoupling / tanking membrane as a matter of course. As your room is under 8m and you say its to be structured correctly then this can be done with Dura-wp the same membrane you would use for wall tanking which is just 0.45mm thick. ( We don't and never have sold Schluter products Dura wp or Dura ci)

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many thanks for any advice given

Have answered above for you thanks again for your order

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thanks for the advice.