The Brew Cabin

Hello,

Great site - but I have not found answer to my problem. I live on small island and have vast quantities of riven flag (probably old roof stones?). I want to lay these in a room 8m x 5m. There is an existing structural concrete floor.

Ideally I wold like to place a layer of Depron on the concrete and then cover this with heating mat. (www.warmfloor.com).

How should the flags be layed on top of this? A thin layer of mortar? Latex tiling stuff? The layer needs to be as thin as possible for heat, but this might mean a cracked floor.

Thanks for your help!

Hi Philip,

because the riven flags vary in thickness, you really don't have much of an option - mortar is the only cost-effective laying material for this sort of application.

A friend in Shetland did something similar and they used a 6:1 mortar for the bedding, carefully selecting flags that would allow them to keep the bedding to a minimum. There was a lot of wastage, but, as you say, there's no real shortage of stone therabouts, so it was worth 'picking and choosing'.

The floor, which I keep promising to visit, was finished with a 3:1 pointing mortar, and then sealed with a matt-finish sealant.

Does that help?