Tiling substrate for a loft?

[Pete G]

Hi there, years since i posted here..

I am going ahead with a loft conversion over the next couple of months.
The builders will be fitting a suspended floor, timber beams covered with tongue-and-groove high-density board.

I'm planning to tile most of the floor area (@20'x18'), & install underfloor heating (on-a-mat electric).

Question is, what should i be attaching on top of the hd board to act as a substrate. Hardibacker? And what should i be using for insulation?

Hope everyone is enjoying their Bank Holiday!

[pjc]

As in MDF ?

[grumpygrouter]

Why don't you have ply laid instead of chipboard? Then you can lay insulating board under the heat mat and skim with SLC, ready for tiling.

[Dave]

Also pete , check that the joists will carry the extra weight, as they are usually not as deep a joist in the roof section as what they are for the floor etc.....

And i would overboard the joists with PLY.......

[Pete G]

Hi, thanks for the quick responses.

The builder is aware i intend to tile & will be replacing the current (1930s) joists with adequate sized joists. As far as i can recall from the conversation, the high-density board is not mdf, but some form of composite, possibly 1.25" thick?
I'll need to double-check that.

But he agreed some other surface material may be required for tiling; i'm still waiting for the surveyor to visit before we get down to detailed plans.

I was also interested in stone-cladding one of the walls, but having looked into this it appears to cost about £90/m !! Has anyone had a go at this?