Tiling on suspended floor with UFH - Tile Advice

[j88koh]

Hi everyone.
I’ve just taken on a large refurbishment of a property. Ive taken the job on from a previous developer who fell out with the customer.
The costumer wants the downstairs of the house tiled but I have concerns about the floor as it is. The floor areas are suspended timber floors, 175 x47 joists the water UFH running between the joists covers in a biscuit mix. 18mm 8 x 4 sheets have been fixed to the joists.
my question is can this be tiled on top of? My thought was to put 6mm Hardy boards on top of this to make it rigid but I’m concerned that the heat source will have an affect on the ply still.
Any thoughts and suggestions would be much appreciated.

 

[Kevbos]

Hi everyone.
I’ve just taken on a large refurbishment of a property. Ive taken the job on from a previous developer who fell out with the customer.
The costumer wants the downstairs of the house tiled but I have concerns about the floor as it is. The floor areas are suspended timber floors, 175 x47 joists the water UFH running between the joists covers in a biscuit mix. 18mm 8 x 4 sheets have been fixed to the joists.
my question is can this be tiled on top of? My thought was to put 6mm Hardy boards on top of this to make it rigid but I’m concerned that the heat source will have an affect on the ply still.
Any thoughts and suggestions would be much appreciated.

You need at least 30 mm over floors like that where floor boards taken up , and the joists cannot be bouncing or moving , ply 18mm then 12mm , use alot of screws then sbr ply , then durabas, coat the durable with self levelling or flexible adhesive !I recommend mapei keraquik , then tile , but allow drying times to take place no foot traffic