Laying flagstones over UFH

[jimbob776]

Hello,
I am converting some old stables and want to have UFH as the primary means of heating the living space.. the area isn't massive and divided into two sections both about 25sqm each..

I have a 5"+ concrete slab already in situ with off course a dpm layer in place first.

Now I'd like to install some 50mm pir insulation with a layer of *dmp and lay 16mm ufh pipes @100mm distance centres and fastening the pipes down with the plastic staples so secure them to the pir insulation.. follow me so far??

What I'd like to do is lay the flagstone using a sharp (screed) sand & cement mix of 5:1 directly onto the insulation and priming the backs of the flagstones as I lay them down..
The flagstones themselves are 30mm thick and the screed bed in which they will be layed on will be about 60mm+

*I've opted to install an additional DPM layer onto the pir as I've heard the foil of the pir insulation can react with the cement mix if your wondering...

My question to you all is can I basically lay the flagstones directly onto pir insulation using the mix I suggested and if so should I include some reinforcement by way of A142 6mm reinforcement mesh??

Your assistance would be appreciated..
Thanks.

 

[Mr Chibs]

What about using some kind of tile adhesive for stone to bond to the screed instead.

You could really do with thicker insulation than 50mm as well. 100mm would be the minimum really.
I have honed limestone floor, that is stuck to a a debonding mat, this mat is stuck down to the screed, with tile adhesive. My tiles are around 14mm thick. Screed is around 65mm thick.

My UFH is 16mm polypipe, sat on red trays. I laid my own, and was going to staple, but changed my mind on the layout, so doesn't effect the PIR like yanking the staples out.

I didn't use any reinforcement mesh.