Advice on insulating a granite house in Aberdeen

[Baz]

Covering a beautiful granite face should be a capital offence. Sure it is porous so not a brilliant performer in the face of horizontal rain but a good gale will dry it out again. If the tiny amount of granite in your walls is giving off enough radon to be a threat then forget insulation, the radioactivity will be keeping your house nice and warm (though you will die from alpha particles burning off your skin). The real problem from radon comes up from below if you are sitting on a big lump of it.