We are about to build a wetroom in our house with asuspeded timber floor, we have decided to go for the Marmox showerstone tray

What would be the best alternative to plywood to fill in around the tray, we are not wanting to use the foam type boards due to point load issues (as we are ussing 2" mosaic travertine on the floor
we are going to be covering the whole floor inc tray with UFH also what would be the best tanking for the floor?

I was planning to just use ply & tank with the rubber tilesafe & then use the Devimat 100 UFH, but if we can get a replacement for the ply & tilesafe we would prefer to use the Devimat 150 (which is to hot for timber & the tilesafe)

Any help & advice would be much appreciated.

I am in the process of doing my upstairs en-suite as a wetroom. I have installed a Tuff2 wetfloor former (Wetdecs.co.uk: Shop Online for Wet room, Screens, Tanking kits, Wet room shower tray formers.) and added extra noggins between the joists, and will be overboarding the floor with 18mm WBP ply. I am installing electric UFH purchased from U-heat (Underfloor Heating | Electric | Floor Insulation | Uheat) but not over the shower tray. I prefer to leave the shower tray without UFH just in case any issues arise longer term and the tray needs to be lifted. The complete floor area will be tanked using Durabase WP but the tilesafe product is also good (I just find it annoying to work with, but performance is good).

If you intend to use the Devimat 150, can you not ply the floor to eliminate any deflection, and then cover with 6mm insulation boards?

first off do all that you can to make sure the sub floor is solid, ensure that you reinforce under the tray also.

I would prefer to use a backer board on a wetroom floor in addition to tanking.

In terms of what tanking/ membrane kits suit what underfloor heating etc, I would discuss with manufacturers for 100% peice of mind. Just be sure to have technical details of each priduct at hand. You will find these on most manufacturers websites.

People do things different ways so I preffer to run things past manufacturer technical dept on subjects that Im not 100%n with.

started writing at the same time as captain

THANKS for the repies Guys,

Originally Posted by Captain Slow

If you intend to use the Devimat 150, can you not ply the floor to eliminate any deflection, and then cover with 6mm insulation boards?

If I used insulation boards, would there be a risk of point loading, the wetroom is going to be tiled with 2" mosaics & maybe used by a large disabled person using disability aids.

I personally dont think it would be aproblem mate. If in doubt check it out! these boards will have undergone tests to adhere to BS so the manufacturer can tell you of any limits it may have. Apparently warmfloor boards take upto 30 tonnes per square metre.

I dont think there would be any probs but best to check if you feel concerned.

I know where you are coming from though as when you look at these boards they look too soft.

JUST ENSURE THE SUB FLOOR IS SOLID & FLAT!

Provided you have eliminated deflection so that there is no movement in the floor you should be fine. You have a choice when choosing "insulation boards", you can opt for standard polycore boards, cement lined polycore boards or cement boards.

As long as the boards are stuck using a flexible tile adhesive to ensure no voids and screwed to the ply they will not be going anywhere. Also, I recommend covering the UFH with a self levelling compound (obviously not the wet former) so that will ensure a flat and strong substrate, too, which will suit the mosaics. Cover the UFH on the wet former with flexible tile adhesive instead of SLC to maintain the correct falls.

I hope this helps.

Daz

You beat me this time TFS

If you aint fast, your last Daz

I agree with Daz, point loading on the boards in mainly associated with installation of the boards and can happen during installation when being compressed by the installer etc. So by getting the floor good combined with a solid fix to the substrate the board well be well bonded to the floor and if you use a good quality cement reinforced insulation board there will be less chance of damage to the board during installation.

Erm why would you cover the tray in UFH? I always thought that it should be avoided?

Originally Posted by dilz000

Erm why would you cover the tray in UFH? I always thought that it should be avoided?

So we have cozy warm feet of course

The whole floor of the wetroom is going to pretty much act as a shower tray, as we are not putting a shower screen in, so if we don't put UFH on the tray the whole floor will be cold.

I have seen plenty of people stating that they put UFH over shower trays on various threads on this & other forums.

I think i confused myself thinking a shower former was the same as a shower tray lol

Originally Posted by dilz000

I think i confused myself thinking a shower former was the same as a shower tray lol

Is that me stating a shower tray when I should have stated former, well I knew what I meant

Sorted now on how I'm constructing the floor see http://www.tilersforums.co.uk/search...earchid=383430 if interested.

Now I am looking for recomendations/advice on tanking the floor & shower tray?
The showertray is one of the Marmox (modified concrete) Showerstone trays, with the surrounding floor boards overlaid with 18mm WBP plywood flush with the tray, the tray & plywood will be covered with a 150w UFH mat.

So what would be the best tanking product to use on the floor? also would you recommend tanking the walls which I am planning to cover with the Marmox boards (even though they should be waterproof (if installed correctly)

again any help/recomendations would be much appreciated

Forgot to add the walls are going to be coverd in 450x300 marble tiles & the floor in 50mm mosaics.

Some shower formers and insulating tile backer boards do have a minimum size tile restriction on them due to the point loading!!! Consult the manufacturer of the products to be on the safe side!!!!

I have never seen any board that says mosaics cant be tiled onto them but, for peice of mind ask manufacturer when working with products you are not familar with and avoid cheap low quality materials.

I remember somebody saying it stated on the packaging that 50ml was minimum size. Best just to phone the manufacturer

Hi, same as above I'm sure Marmox say 50mm is the smallest you can go, as for the walls i nearly always use marmox board and aslong as it is installed and jointed properly I don't see any reason to tank over it.
Good Luck
Gary
plumbingsolutions@ntlworld.com