Tiling over under floor heating (Devimat)

[john raymond]

Hi Guy's
Having put down a devimat on a concrete bathroom floor, do I need
to
1. cover the mat in a self leveling compound to give me a smooth level base to work off.

2. Just apply the adhesive to the mat, then lay the tile

3. Apply the adhesive to the back of the tile only, to prevent possible damage to the electric mat caused by the trowel.

Your comments please

John

 

[nybor62]

slc over the mat ,have u tested it

 

[diamondtiling]

Cover with a flexible SLC to protect the wires. Did you use insulation on the concrete? if not you will be paying to heat the concrete.
Remember to check your readings before and after laying the tiles.

 

[nybor62]

well said diamond i was just about 2 say i know off a few people who have had problems getting the heat into the tiles , is it the 150 w mat for concrete

 

[john raymond]

Thanks guy's,
It's not too late to do any of the things you recommened.

John

 

[DHTiling]

Hello John..

It is advisable to use a 10mm minimum insulation board fixed to the concrete with tile adhesive ( flexible) and then lay out your devi mat on to this.. this will increase the warm up times and no risk of loosing heat into the substrate.

A hot melt glue gun will be handy to stick uneven parts of the mat down as re-lifting it might cause the mat to lose it stick..

You will need a levelling compound suitable for use with UFH systems and ones i recommend are Mapei Fibre plan or Pci hsp34.. both are fibre enhanced and flow very well.

The reasons for using a leveller over the heat mat is to protect it from damage whilst tiling and also it fills all the voids within the mat and lessens the chance of cold spots .. make sure you use flexible adhesive and flexible grout..

If you let us know where you are we could advise where to get that from as well..

You should have full fitting instructions in the devi manual, so make sure you test the mat before and after installation and install the probe as well , as some peeps do forget about the probe.

Any further assistance then the members will be here to help..

 

[john raymond]

Thanks for that Dave,
If you could let me know where to get those products you suggested, that would
be appreciated, I am in the Salisbury area (Wiltshire)

Regards,

John

 

[DHTiling]

You will get the SLC at tile giant.. you can source a store near to here>> Store Finder as for the insulation boards then wickes sell them .. or you can order on-line here.. Underfloor Heating | Floor Insulation | Uheat

 

[Gazzer]

No sense in overlaying in plywood, just be sure to use powdered flexible adhesives and flexible grouts. you must also allow the screed to cure properly before tiling, one inch per week, is the drying time. After you have finished tiling, the customer must wait 2 weeks before running the UFH, and it should be increased by 5 degrees per day till max, and the same down to off, this gives the add and grout chance to accustoms to the temerature changes

1mm per day here mate.

 

[davemul]

ignore me! old thread!!