3/4'' flags on underfloor heating

[Tiler Dan]

Hi. I,m laying 3/4'' flagstones on top of underfloor heating. I want to lay them with mortar but i'm not sure what mix to use.I have been told a 4:1 but not sure can u help.

I also need to know what sand is best to use and if i need to add anything to the mix to make it more flexible. If so what would you suggest.

By the way great website you have here very usefull.

[GB_Groundworks]

Read the main site it's explained it detail there,

But yeah 4:1 of course sand (sharp, grit, plastering etc) not bricklaying sand

You can add plasticer or sbr to enchance the mixes consistency or strength with the sir.