warmup insulation boards - question...

[Grace'sDad]

My customer wants to save money (don't they all!) by only installing warmup boards exactly where the heating is going to be - approx 10sqm in a 17sqm room. She is sure that they will not move furniture and that the layout will be fixed.

My question is if I bond boards to the sand and cement screed (as usual), can I then bring the rest up to level with a good flexible slc, or will the two different substrates cause trouble? Surely warmup boards, slc and s&c floor are all pretty stable together.

Tiles are to be 300x450x15mm polished marble.

Thanks!

 

[wayne]

wont it cost nearly as much for the slc as it will for the boards?

 

[Grace'sDad]

My 1st thought too but 6mm per board works out about half the price.

Only asking the question - personally I dont want the hassle and dont think its worth it. I'll end up charging more for mucking around!

 

[grumpygrouter]

A couple of bags of Mapei Fiberplan should sort out the difference 'Dad, you may be right, fully boarding out my be quicker and cheaper. For your tiles I would be inclined to Ditra/durabase too, marble is well soft!