Tiling Advice Wanted - Over Wet UFH

[swampie]

31mm of heat resistant wood
my advice bin the marble tiles the product I would lay would be karndean or amtico

Just spoke to a friend who lays vinyl floor and he also says the Karndean and Amtico have been known to fail as the heat melts the glue on occasions so I've a risk either way.

 

[Ajax123]

Why a biscuit screed?? it will hardly get warm with all that stuff on top...

 

[Ajax123]

you could use a high temperature adhesive. There are quite a few available these days from the likes of Sika and others.

 

[swampie]

Why a biscuit screed?? it will hardly get warm with all that stuff on top...

Considering my floor construction and not wanting to raise the floor level, I wanted to install the UFH between the joists.

The decision to use this mix was made after several UFH suppliers confirmed that this system was the best U-Value compared to the metal trays which are already routed out for pipework and was the only other offered by my supplier without raising floor levels.

UFH companies don't really push this system as they'd rather you bought the products but trust me it works so far & I'm sure the tiles will warm. The system so far has been on for months now. It is nice and warm underfoot.

I have already finished the bathroom and in fairness, the tiles are not warm to touch before the room is up to temp, but that is a small room and heats easily. My kitchen may well require a higher heat.

See the design here

 

[mike1979]

Do as bri says take the ply board up and use a decent tile backer board laid in flex adhesive and screwed down then a uncoupling membrane on top should be fine to tile I use nicobond matting as I find it fairly thin and easier to use

 

[swampie]

Do as bri says take the ply board up and use a decent tile backer board laid in flex adhesive and screwed down then a uncoupling membrane on top should be fine to tile I use nicobond matting as I find it fairly thin and easier to use

Who supplies the nicobond Mike? I can't find any suppliers. Will my builders merchant stock it?

 

[swampie]

I understand the decoupling membrane now but what exactly does the backer board bring to the party that the ply is lacking?

 

[White Room]

Hardie dos'nt get affected with moisture...

 

[Ian]

Backer board won't expand and contract like the ply with the heat from the floor, plus, it's stuck to the substrate as well as screwed adding a little more in the way of rigidity (hardie will tell you it adds no strength but, those who use it know that it does [emoji106]) here's a couple of pics of an identical arrangement to yours except the tiles are limestone

 

[mike1979]

I buy it direct from nicobond I just prefer it over other membranes but I don't want to start a debate on it with others please I know what your all like !!!