I have laid a UFH mat on top of No-more-ply sealed with Bal WP1 , with a trench for the probe cable and the power cable, both of which are in pvc tubing.

Q1 Do I lay the tiles directly on top of the Heat mat or do I apply a layer of tile adhesive on to the heat mat and then lay tiles when the first layer is dry?

Q2 is the probe itself embedded in the tile cement, or does it sit in the pvc tubing?

I am using Bal PTB flexible with admixture GT1 and Porcelain tiles

Best practice Alan is cover the mat with a self levelling compound (Mapei fibre plan is good) this protects the cables whilst tiling.

Probe wants to be in the tubing, this is so it can be removed if it develops a fault.

Would a layer of the PTB flexible not be OK instead of the self levelling compound?

Originally Posted by AlanJeans

Would a layer of the PTB flexible not be OK instead of the self levelling compound?

Self levelling compounds (good ones anyway) do what it says 'on the tin'!
i.e. gets you a good flat surface to work off. You realy don't want to run the risk of damaging your (expensive) mat with a trowel. Won't achieve much of a flat surface either. Pays your money takes your choice Alan.

UHeat do a nice little monitor to keep tabs on your mat while you work on it too.

Originally Posted by faithhealer

Best practice Alan is cover the mat with a self levelling compound (Mapei fibre plan is good) this protects the cables whilst tiling.

Probe wants to be in the tubing, this is so it can be removed if it develops a fault.

Perfect advice from faithhealer

Hi

Make sure your probe sits approx 500mm into the room. It should be evenly placed 'between' the heating loops - not under/across. Its ok to use adhesive to bed the mat, but its far easier and less problematic using slc.

Also I would butter the underside of the tiles prior to bedding to ensure a good bond

I was a bit concerned about using SLC and losing my falls, and also of clogging the drain!

Stick gaffer tape over your drain if your worried.

You wont loose your falls as you lay the slc to the ufh cable depth - 3mm

Also make sure you use a 2part slc with latex