Underfloor Heating in Wetroom

Tester46

My new build extension has a wetroom (basically a shower/WC that is tiled all over so it can all get wet from the shower. In order to make it comfy in the winter, and to help it dry out after a shower, we are installing electric underfloor heating mats under the floor tiles, on a timer.

When the concrete screed is poured, does the heating mat go on top of that, followed by the tanking (i.e. some form of rubber sheeting), followed by the tiles? Is tanking even needed - the wetroom is ground floor and a plumber has told me the heating mats are earthed and don't need tanking (!!!)?

browner85

as far as im aware it has to be tanked and the heatmat goes straight under the tiles in the adhesive.

Joey the lips

browner85 wrote: »

as far as im aware it has to be tanked and the heatmat goes straight under the tiles in the adhesive.

Yes you need tanking and yes my understanding and practice has always been

Tanking
Unfloormat
FLEXABLE adhesive
tiles
flexable floor grout.

Most important: ensure a circuit test is done on the mat before the flexable adhesive and tiles are layed. Do not assum it works it sometimes does not.

If the mat is being cut. Ensure the circuit line is not cut only the netting.( Its usually cut to go around corners)

a note of caution on underfloot matts. Check how they work one popular brand of mat has a hunting sensor and what is does is constantly send out a current and test the circuit. You would imaging this is good but it actually leads to expensive running costs. My thoughts are that this is unnecesary if the circuit is tested correctly.

Potterton myson do a very good boxed pack with "Everything" in the box it does not hunt and its reliable but its slightly more dear than the normal ones.

Carlow52

Tester46 wrote: »

My new build extension has a wetroom (basically a shower/WC that is tiled all over so it can all get wet from the shower. In order to make it comfy in the winter, and to help it dry out after a shower, we are installing electric underfloor heating mats under the floor tiles, on a timer.

When the concrete screed is poured, does the heating mat go on top of that, followed by the tanking (i.e. some form of rubber sheeting), followed by the tiles? Is tanking even needed - the wetroom is ground floor and a plumber has told me the heating mats are earthed and don't need tanking (!!!)?

U might consider 2 switched/timed circuits if the b/room is big

I trust the underfloor insulation is already in?

browner85 wrote: »

as far as im aware it has to be tanked and the heatmat goes straight under the tiles in the adhesive.

I presume the tanking is a wet-room requirement and not related to the heating: Am trying to learn here:)

Joey the lips

tanking is a water sealing requirement. Its usually painted onto the plywood or concrete floor. Tape and specific plastic pcs are applied at joints
(Tape) and corners(Plastic pcs) the tanking is then painted over this. Tanking is usually only applied to the waste height/shower valve height but I have always applied it higher usually up to the shower head. This is overkill but why not. Better to be safe.

More importantly I never rec a wetroom upstairs unless its on mass concrete floors. It gives to much trouble

later

Hi

I did it in 2 bathrooms - one on plywood and one on concrete - plywooded room much faster to heat up - regret not putting down an insulating board in the concrete room.

I find it great for the winter ( in the concreted room - other is fine ) and when bathing the kids


Tanking is required mostly for the plasterboard wall and any joints including the shower valve - used a paint on stuff called BAL myself - working fine - goes on before the mats as Joey says (see http://www.w**********n.htm )

got the mats from

www.t**********x.html

(I have no connection with them - was quoted mad money from irish suppliers )

- main thing is the cable cannot be cut so make sure if you are not heating under sinks or toilets that you do not get too big a mat. Also there is a piece of flexible conduit for the floor thermostat that needs to be in a channel under the heating mat


edit: keep recommendations to pm only...
syd

Tester46

Joey the lips wrote: »

Yes you need tanking and yes my understanding and practice has always been

Tanking
Unfloormat
FLEXABLE adhesive
tiles
flexable floor grout.

Most important: ensure a circuit test is done on the mat before the flexable adhesive and tiles are layed. Do not assum it works it sometimes does not.

If the mat is being cut. Ensure the circuit line is not cut only the netting.( Its usually cut to go around corners)

a note of caution on underfloot matts. Check how they work one popular brand of mat has a hunting sensor and what is does is constantly send out a current and test the circuit. You would imaging this is good but it actually leads to expensive running costs. My thoughts are that this is unnecesary if the circuit is tested correctly.

Potterton myson do a very good boxed pack with "Everything" in the box it does not hunt and its reliable but its slightly more dear than the normal ones.

All good advice - thanks