The regulations are pretty severe If there's anything combustible (like floorboards) tou need something like a 6" layer followed by a 2" air gap.
There was a question here about a week ago where someune had used a layer of firebricks and found that the floorboads beneath were getting worryingly warm
Hi Julaz, if you are thoinking of putting them down as a base under a real fire,roofing slates really aren't thick enough,they will eventually break up with the heat, try to get some thicker pieces of slate for that and use the lime mortar on it. Ray
thankyou jake,the whole floor is concrete and i was going to lay them on top of old paving stones,excuse me if this answer goes in the wrong place Im new to answer bank.
cheers
Hi Raysparx1,
yes I agree with you,just when I was trying the tiles out I found them very fragile,so I will get some thicker slate.
Thanks very much for your help.-