Hi All,

New to the forum and after reading some of the threads on here i'm now a little worried.

I'm in the process of converting the attic to a nice onsuite with a walk in wetroom shower, unfortunately I have already put a showerlay tray in and this is now fixed in place with its drain etc. While fixing it I was a bit concerned about its rigidity and I am now wishing I had found this forum before and at least gone for the more rigid version...

Anyway, am I now doomed or will this be ok once tanked and tiled? I am looking at stone 50mm mosaics which are in line with the manufacturers specs.

Andy

Hard to say for sure without seeing it but I should think you are ok.

Have you had a good read through the paper work that came with the tray? If they say that it is suitable for tiling onto and you have fitted the tray and tiles correctly you should be fine.
If you are unsure, give the manufacturer a ring, they will tell you straight away.

What were your concerns on the rigidity ?

Marmox onto joists.... explain your installation method.?

Hi Guys,

This is a Marmox Showerlay Preformed Tray, it's lay on top of 22mm chipboard with a 6mm Ply, it is done as per the manufacturers guidelines but it is one of the foam trays, pressing down on it you can feel compression. The manufacturer guidelines say you can use upto 50mm mosaic tiles without getting compression points but i'm not exactly a small guy!

My concerns may be unfounded but I am still concerned.

Andy

Welcome Andy

if you have fitted the former correctly as per the marmox instructions then it will be fine.

if you have just layed it over the joists with no support or box for the waste then it probably will fail.

correctly fitted and tiled 48mm mosiacs are fine on the showerlay former

6mm ply?

Originally Posted by dilz000

6mm ply?

I think the pre formed tray has been set onto 6mm ply, dont think he meant that he is tiling onto 6mm ply... I hope

Originally Posted by Dylante

I think the pre formed tray has been set onto 6mm ply, dont think he meant that he is tiling onto 6mm ply... I hope

I think the intention is to tile over the 6mm ply screwed at 150mm centers to the 22mm chipboard. Is this wrong? The tray fixed to this with fleible adhesive....

Andy

Im afraid this is wrong, min of 18mm BWP ply on the floor. Any tiles put down onto 6mm ply WILL crack and lift sooner or later. I would get shot of the ply and get yourself a backer board like No More Ply or hardie backer, you can use 6mm backer board.
A backer board will be slightly more expensive than using the ply but will give you the substrate you need.

If you want some info there are lots of threads on here about the benefits of using backer boards over ply and there are hundreds of threads advising against 6mm ply on floors. Have a search

Originally Posted by Dylante

Im afraid this is wrong, min of 18mm BWP ply on the floor. Any tiles put down onto 6mm ply WILL crack and lift sooner or later. I would get shot of the ply and get yourself a backer board like No More Ply or hardie backer, you can use 6mm backer board.
A backer board will be slightly more expensive than using the ply but will give you the substrate you need.

If you want some info there are lots of threads on here about the benefits of using backer boards over ply and there are hundreds of threads advising against 6mm ply on floors. Have a search

I'm sure you can understand why this was not what I wanted to hear!! The builder has put this down and was supposed to be laying the tiles also, does it help or make it worse that there will be underfloor heating down too with SLC over it?

Did I read right that you can tile strait onto chipboard nowdays with the correct adhesive?

Andy

No it doesnt make it any better Im afraid, 6mm ply is just to thin. The ply will expand and contract with the heat of the UFH and 6mm is just far to thin to stand this kind of punishment, min 18mm BWP should be used on floors and even this isnt ideal. The problem is that very few builders seem to know this. 6mm backer board is by far the best way to go.

If the bulider isnt happy about it then tell him that the above is in accordance with britsh standards. Just be aware that the backer boards need to be glued and screwed down to fill any voids under the boards.

Originally Posted by dilz000

6mm ply?

Well spotted mate

Originally Posted by DarkyUK

The manufacturer guidelines say you can use upto 50mm mosaic tiles without getting compression points but i'm not exactly a small guy!

I Spoke to Harry @ Marmox the other day,
I explained that we are using 50mm mosaics and that the room may be used for a large disabled person ie using disability aids,
He was pretty definate about using the showerstone instead of the foam showerlay due to point loading, even though there website state that 50mm mosaics are ok.

Hope this helps