advice on tilie onto tile

[kilty55]

hi all,just ben to look at a job the customer has a bathroom with existing tiles on top of ply which he doesnt want to lift,also on top of this he wants to lay underfloor heating mat can i tile straight on top of this or do i need to prep tiles 1st in some way? cheers

[andy-p]

no way!! the tiles need to come up , you have to ensure that the ply is fitted correctly and of sufficient thickness, if fitting ufh you should also consider insulation boards or insulating tile backerboard!!

[garythetiler]

totally agree with andy p you would be mad to even consider it

[kilty55]

cheers,so tiles up and then a sufficient thickness of ply and i can lay the tiles on top of this adequately?

[smokey1234x]

but if the tiles which r down r not givin any problems and r fixed well then the floor under them is good,dont see y u can not tile over with flexi if that is what the customer wants,but the floor level will b higher

[Pawelzik]

Because:
- Floor level too high, something the customer doesn´t want
- You are loosing heat transferred to the old tiles, something the customer doesn´t want
Better to do 1 job 1 time right.