Mosaics over electric UFH & chipboard?

[benraz69]

Installing an Impey wetroom former/tray & tanking kit. The floor will be tanked, then electric UFH, then mosaics... but before that, the existing subfloor is P5 grade chipboard which is in good condition. I assume I'll need something over the top of that before tanking, i.e. thin ply/tile backerboard/decoupling membrane. If so, which is preferable with tanking + electric UFH? Or am I better to take up all the chipboard flooring & start again with ply?

Secondly, what's the best way to get a nice flat surface after laying the electric UFH (4mm) - ready for the mosaics? Can I just use level it off using floor tile adhesive, then come back the following day & lay the mosaics?

Thanks in advance

 

[Lee@TileTown]

Best way to prepare the surface is to use a flexible self levelling compound.

If you use Tilemaster Rapid Level 30 you can level be tiling in 45 minutes.

 

[L95]

Best way to prepare the surface is to use a flexible self levelling compound.

If you use Tilemaster Rapid Level 30 you can level be tiling in 45 minutes.

Straight over chip? Didn't think it would bond to chip which is why I'd say 6 mm Hardiebacker personally. Will have to look into that gear though.

 

[Lee@TileTown]

Straight over chip? Didn't think it would bond to chip which is why I'd say 6 mm Hardiebacker personally. Will have to look into that gear though.

Yep, ideal for plywood overlay.

From the tech sheet:
Plywood Overlay: Prior to applying Rapid Level 30, ensure that new or existing boards are dry, i.e. conditioned to the environment in which they will be used. Plywood must be 6mm (minimum), exterior grade, screwed (not nailed) to substrate at 6 inch/150mm centres. Ensure there is sufficient ventilation beneath substrate and that the plywood has been fitted competently and will take the weight of the leveller, adhesive and the final floor covering being applied. Make sure the surface is dry and free of any contaminants, loose dust or dirt. The top surface of the plywood does not require priming prior to applying Rapid Level 30. Prime the reverse side and edges of the plywood with neat Primeplus.

 

[L95]

Yep, ideal for plywood overlay.

From the tech sheet:
Plywood Overlay: Prior to applying Rapid Level 30, ensure that new or existing boards are dry, i.e. conditioned to the environment in which they will be used. Plywood must be 6mm (minimum), exterior grade, screwed (not nailed) to substrate at 6 inch/150mm centres. Ensure there is sufficient ventilation beneath substrate and that the plywood has been fitted competently and will take the weight of the leveller, adhesive and the final floor covering being applied. Make sure the surface is dry and free of any contaminants, loose dust or dirt. The top surface of the plywood does not require priming prior to applying Rapid Level 30. Prime the reverse side and edges of the plywood with neat Primeplus.

Ah its me being a donut then and forgetting about the plywood overlay!