Would you go ahead and install?

[Fatpipe22]

Hey guys,

First time installing shower tray at home, its a Mira Flight Low , 1400x900 onto marine ply floor which has been strengthened with noggins as much as possible. Turns out I've got a high point of +3mm in one corner (with the level across the edges). I've done a basic water flow test and it appears fine, but its clearly nothing like simulating a running shower. I've checked the inner tray with a smaller level and there is a clear run to the waste from all sides, but more pronounced on the side with the 3mm high point.

I was intending to use CT1 to bed the tray as can forsee me making the levels worse if I attempt to bed on sand / cement mix.

1. Would you attempt to correct the 3mm when fixing the tray
2. Would it be feasible to simply add less silicone to the high area (still some) in the hope it would reduce the difference?

Shame as all the other measurements a bob on, I'm basically cautious of messing round too much with the levels as I'll likely make things worse! Plus, I was hoping to have the tiling done this weekend!

Thanks in advance, ANY advice / views are very much appreciated.

G

 

[SimonG]

Bed on flexi tile adhesive. Level it on that.

 

[Fatpipe22]

Thanks Simon.

Assuming that would need the ply covered with SBR?

Worth saying that the ‘bob on’ measurements are exact and the tray is VERY snug between the 3 walls, meaning that it will be a significant challenge laying onto a bed of adhesive or cement without making a hash of it.

would you advise against trying to level with the silicone as it won’t work or because your preference is for adhesive?

really appreciatethe response

 

[centralheatking]

Put sound insulation under the tray if it’s on a suspended floor with rooms below, between the joists

 

[Fatpipe22]

Too many pipes for insulation or anything between joists.

I've dumped a load of water from a big Flexi-bucket onto the tray. Theres some migration to the lower side, but not enough to come close to spilling over the side. There is a still a decent fall INSIDE the tray and all water drains away.

I'm looking at using a self leveller and then silicone, or just silicone. Sand / cement or adhesive won't be an option as I'll have to remove the backer boards.

 

[Ben-gee]

We advise against silicone because it allows movement which you don’t want. It is also against manufacturer instructions for the same reason.

As SimonG says, your best bet is flexible tile adhesive - use rapid set as you said you wanted to tile it asap.

If you’re on marine ply then prime it with acrylic primer first ( if you already have sbr that’s fine too).

If you have to remove the backer boards then do so, or are you just waiting for someone to validate your method?

 

[Fatpipe22]

We advise against silicone because it allows movement which you don’t want. It is also against manufacturer instructions for the same reason.

As SimonG says, your best bet is flexible tile adhesive - use rapid set as you said you wanted to tile it asap.

If you’re on marine ply then prime it with acrylic primer first ( if you already have sbr that’s fine too).

If you have to remove the backer boards then do so, or are you just waiting for someone to validate your method?

Thanks Ben Gee

Silicone is advised for securing to the ply on the manufacturers instructions, that or sand cement.

Yes, waiting for someone to validate!

Likely going to remove the backer boards. Discovered the level I've been using was duff, bought a new one and sods law I've found one of the shower walls is 4 mm out as well. Tiling should be fun.

Should have paid an expert to do it or checked my spirit level for accuracy. Idiot. Not a happy man.

 

[Ben-gee]

Could be worse, you could have paid an idiot to do it! (masquerading as a professional)

At least you’ll know it is all done right, and you’ve got a nice new shiny level too.

Good luck, sounds as though you are being nice and thorough so should turn out well.