Tiling over underfloor heating mat

[leee]

Have got a sound concrete slab floor (Flat and level) 10m2 and am laying electric heating mat.

One supplier has recommended 10mm insulation boards down then mat, them adhesive and tiles (They sell the boards by the way !! ) Another has said don't bother with the boards as my concrete slab has 70mm insulation under that and the cost of the boards v's running costs = savings will be nominal.

First question is who's advice would you follow re the backing boards ?

Secondly - It says i must use a 2 part flexible adhesive - Upon searching this various brand names have been mentioned namely BAL,Dunlop,Granfix etc all of which are really expensive £20-£30 per 20kg bag ? and also quite confusing. Does anybody use a good flexible adhesive suitable for under floor heating that is reasonably priced ?

Thanks Lee

 

[JohnD]

If you are heating the great concrete slab, it will take a long time for your room to get warm (also to get cool). This may be OK in the winter when you are heating it every day with cheap night electricity. Like storage heaters, it is convenient if you have babies or old people who are at home all day, but a waste of money if you are out at work.

If you have insulation under the mat it will be quicker to get warm (and cold).

However if you are going for electric floor heating I presume cost is not a concern.

 

[gcol]

However if you are going for electric floor heating I presume cost is not a concern.