Tiling over existing flag stones

[Peter P1234]

Hi All, I'm hoping you can offer some advice to help solve an age related problem.

I have an existing floor with concrete flag stone tiles, its only small around 4m2 and is used as the dogs area.

The dog is getting on a bit now, and we'd like to add some underfloor heating so his bed & rug is warm instead of the cold floor.

The question is whether this can be done over the existing floor? Ideally it would be an electric underfloor heating mat direct on to the editing flag stones (they are fairly level, no major undulations), then levelling compound and finished with a vinyl flooring of some sort.

The finished floor level can be raised by 15mm without any issues of skirting or thresholds.

Or would it be best to put levelling compound on the flagstones first , then mat and more levelling compound?

Or would the only option be ripping out the existing floor to start again?

Any help and advice you can offer would be greatly appreciated.

Pete

 

[eddcottee]

I'd prime the tiles with SBR, then self level over them, then i'd put down Warmup Ultralight Underfloor Heating boards or similar as these will reflect the heat upwards and will be sat nice and level, so you get even heat distribution. Also, you wont be losing heat downwards through the floor. Then electric heat mat on that, self level over the heating wire and then your vinyl on top of this.

15mm should give you more than enough for this, however if tiling on top of it all, you'd probably need to break out the existing tiles. Also if tiling, the Warmup Ultralight boards act as a decoupler aswell, so you'll be protected from lateral movement due to the UFH.