Hi, I'm at the stage in my bathroom of fitting the prowarm underfloor heating insulation boards and am just looking for some advice. I was under the impression you fitted them with flexible tile adhesive when it is a screed/concrete floor and fix them at 300 centres using appropriate fixings when it is a timber floor, I'm now questioning weather with a timber floor I should also be using flexible tile adhesive underneath before fixing? How do you do it? It seems over the to use adhesive aswell but maybe im missing something. It is the prowarm unfloor heating system with 6mm prowarm insulation boards. Any advice would be appreciated. Thanks
I’ve not used Prowarm boards specifically before but most other backer boards require the use of adhesive. This isn’t really to stick the boards to the subfloor but more to fill any voids or hollows between the two. Just comb a bed of adhesive, I use a 10mm trowel, to the timber floor and set the backer board into it twisting slightly as you do so. Fix the board down with 35mm washers and screws, normally 15 per board, 600 x 1200, whilst adhesive is still wet. I have removed several floors in the past that have failed where adhesive hasn’t been used.