Best way to level over underfloor heating on an Impey membrane?

[ojtiler]

Hi,I'm installing an Impey tilesafe membrane on my wetroom floor and want to install underfloor heating. Impey recommend installing the ufh above the membrane and also say that fitting the ufh cable over the shower shower tray area to within about 150mm of the drain would be OK if I want to do that. (This would be my preference for comfort and quicker evaporation from shower floor area after showering).This presents a problem; I want to apply self levelling compound over the heating cable to get everything flat & protected for tiling, but I'm concerned the self levelling compound is going to flow down across the shower tray and obviously end up setting non-level. Even if I decide not to put the ufh cable over the shower tray itself (i.e. restrict the ufh to the main floor area), the slc will be wanting to move with gravity down the gradient on the shower tray?!!So what's the best way of going about this aspect of installation? i.e.

• should I put the ufh cable over the shower tray?
• if I do this, how do I protect the cable on the tray area?
• if I restrict the ufh cable to the main floor area, how do I stop it draining/becoming uneven on the tray (with a dam??!)
• If so, how do I get it even over Photo of the shower tray is below (I haven't fitted the membrane yet)

Would really appreciate any advice on this one....Many thanks.

 

[Time's Ran Out]

:welcome: I can see the flow problem into the falls of the tray so I'd use a fast set flexible adhesive to cover the wires in that area and applied with a rubber float to smooth it.
I'd also be aware that Impey used to recommend only a mat of up to 100w for UFH (will have something to do with it melting the membrane:lol🙂.

 

[Mike Mike]

You need a self-adhesive, foam strip which you stick on the floor around the tray to stop SLC running onto the tray and into the drain. Avstängningslist - 30x30mm, 2m, blå - BYGGmax

(Do they not sell these in the U.K.??? If not, then maybe someone should consider importing and selling them. They're a couple of quid each, you can stick one on top of another to get a 60mm barrier, and they are flexible so can accomodate curved or other shapes required).

IF you decide to put the wires onto the tray, then seal around foam strip with acrylic fog as well, to ensure they are a tight seal (you will need to scrape this off when the SLC has dried).

What we do (because regs say you must have a fall across the whole room towards the floor drain) is set up a plank or two, so you can access all the corners of the room. I use two cut down sections from a pallet, place one on the shower tray, and one in the hallway outside the bathroom. Then run a plank between the two. You can now walk from the doorway to the shower tray.

Then, pour the SLC from the doorway wall ONLY. Pour it slowly and let it run down towards the tray. Do the same from the other wall(s), pouring the SLC along the wall and letting it naturally run down towards the tray. It takes skill and practice to get it right and not end up with 2cm of SLC all around the tray, LOL, but if you take your time and be patient (can take at least 5 minutes for it to stop running) then you can achieve a perfect, flat, fall around the entire room.

For the shower tray iteself, we don't have pre-formed trays and so have to create the fall ourselves using low slump smoothing compound and various different length pieces of wood.

For your tray, and that complicated shaped drain, as Timelss-John says, use a flexible adhesive to cover the wires.

I would recommend trying to pour the SLC as I have suggested though so that you don't end up with a high lip all around the shower tray, which is a risk if you just try and pour it level across the room....

Good luck!

 

[ojtiler]

Hi,


Really appreciate your guidance with my query....


Many thanks.

 

[Impey Showers]

Hi ojtiler, if you are installing products above our Impey Dec then I would seriously advise a cal to our technical department so that you are aware of the correct procedure to maintain the lifetime guarantee. The direct line to technical help is 01460 258 682


Thankyou

 

[ojtiler]

Thanks, Impey. I did indeed put a call into your tech dept. - very helpful, thank you.

 

[bugs183]

Hiya!! As Timeless says use a flexible adhesive in the tray.
Put the mat loose on the tray and make it fit as you want.
Take a photo so that you remember the layout.
Mix adhesive and trowel it onto the tray with a 6-8mm trowel, make sure the notches are high and consistant, no areas without adhesive. This will key the adhesive to the tray, vital!
Now place the mat as laid out before and press the mat into the adhesive. Now spread some more adhesive over the mat,and with a grout float thoroughly covering all the wires, you don't want any voids.
Smooth over with the float and a damp sponge and leave to dry.