Hi there!
I hope someone can help with this, as I've been going around in circles!
We are renovating a stone walled barn in France - the walls are approximately 2ft thick, with two skins and a rubble cavity. Between the stones is a lime mortar (although we're repointing inside and out).
My main issue is the breathability of the building and mitigating condensation - I don't want to apply modern insulation techniques that are going to damage the fabric of an old building.
I have been advised to install a breather membrane directly to the stone walls, then with a 50mm cavity before the stud work, then we're using 140mm sheep's wool on top of the stud to help with the breathability, then a vapour control layer on top and then finally the plasterboard.
Is the breather membrane necessary? As the stone and lime mortar will allow the wall to breath. Thermafleece's tech support said a breather membrane isn't necessary, neither a vapour control layer - they just said I need the cavity, the sheep's wool and then plasterboard on top.
Rockwool advised the full set up of breather membrane, cavity, stud work, insulation, vapour control and then plasterboard.
Any help or advice would be very gratefully received!
Thanks!