We are thinking of installing indian sandstone flagstones in our old slate cottage. The concrete sub-floor was laid before we purchased and I presume it doesn't have a watertight membrane, however there seems to be no problem with damp in the property.
I would like some advice on the following points:
-do we need to put a fresh screed down on the floor with membrane
-do we need to install insulation between the flagstone and the concrete sub-floor (will it be to cold baring in mind the house is a fairly warm house)
any advice would be great!