Underfloor Heating Advice

[stroller133]

Hi

I am due to move house in April and we are planning to tile the Kitchen/Dining room. It is open plan but with a dividing wall about 2/3 of the length of the room so the areas are a bit separate. The current flooring is lino in the kitchen and carpet in the dining area.

We want to tile,as I think it will look much better and will be easier to keep clean with the children and the dog.

The total area is approx 16' X 12' with each section being about 50% of the space.

The room has felt nice and warm when we have been to view and is heated by a large radiator in the Dining area. The house is a modern, David Wilson Homes build (approx 2005) and I imagine is concrete floors.

The advice I require is:

1. Would undertile heating be advised for this application
2. If so would you advise background heating for floor surface only or turn off the radiator and use a bigger undertile system to heat the room
3. Assuming the concrete is flat, are backing/insulation boards required or are mondern floors already well insulated.
4. Is the floor probe necessary - as I believe this will involve digging up some of the floor to install and will increase the installation costs.
5. If 2 systems are required can they be controlled one probe and controller?



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[vargen]

Bear in mind I'm not an expert just a DIYer....

Underfloor heating is (generally) more efficient than a rad system, as the heat rises uniformly through the room without creating any draft. I would dispense with the radiator and go for u/f as the principal heat source.

You'll need to check with the builder on the precise construction of your floor, but I'd guess you are right and it's poured concrete.

Insulation/backer boards are normally required to ensure the heat is not wastefully lost in the screed/concrete beneath the heat source. Most recommend 10mm minimum board thickness but the thicker the board the more efficient the system. You would need to fix the boards to the sub-floor with a suitable flexible adhesive which is compatible with the final finish. I used BAL Green Screed to stick the boards for a ceramic tile finish in my bathroom. You can also use a reflective primer on the sub-floor.

The floor probe is important, really, tho' you can dispense with one and just use a stat with an 'air only' setting. The probe is normally fixed in conduit in the insulation/backer board, so hacking up the floor screed isn't necessary and would only require a small channel cut in the screed if you don't use backer boards. Lay the board first and then cut out a suitable channel.

I would recommend using a floor leveller over the heating cables/mat before tiling for safety's sake, though you can just bury them in tile adhesive as long as you do bury them; just ensure there are no tiles directly in contact with the cables.

Within limits you can connect multiple systems with a single probe and stat.

Hope this helps...