insulating old stone house

[Daisybell1]

I'm finally getting my new kitchen! I'm so excited but the builder has suggested using breathable insulation on the walls to allow the stone work to breathe.
He suggests using thermafleece with breathable board on top but this would mean up losing 12cms around the room. It's not the end of the world but I did wonder if there were any other solutions...

a dry-lining solution, with insulation behind plasterboard, is the usual treatment. You can get Kinsgpan or Celotex products, which have the same insulating power as twice the thickness of mineral wool, and can incorporate a moisture barrier and a plasterboard face. In modern houses the moisture comes from inside the house, so a barrier is used to prevent it reaching the wall and causing condensation. I would not expect to use a breathing treatment as I would expect it to cause interstital condensation. I would go for a barrier system, if necessary with the gap ventilated to the outside. The wall "breathes" to the outside, not the inside of the house, which will be relatively moist.

However I am not experienced with old stone houses.

Unless you have total confidence in your builder, and he can let you visit other old stone houses that he has treated in the same way, I would suggest you seek further advice.

I would be very worried about the risk of condensation forming behind the drylining if there is no vapour barrier. You can, I think, find useful documentation on the Kingspan site.

p.s.
I see Thermafleece is the sheeps wool product. If you like that, and are mothproof, have a look at their website to see how they recommend drylining.

Be very careful about insulating solid stone walls - English Heritage have some good guidance here whether or not your house is listed.

Thank you, that's great. The English heritage is very useful. We've seen the proposed system in use in a listed building and that ties in with what English Heritage recommend. Everything would be breathable and I don't think there would be a vapour barrier at all. I don't think it's cheap though...

Just looking on the thermafleece website and they say to use a vapour control layer

...we seem to disagree with your builder

Have a look here - the multifoil is very thin but has the same insulating properies as a thick slab of kingspan so you would not need to lose so much depth from the walls.
It is worth phoning/ emailing them to ask their advice.

'mmm

I'm not sure that it does have the same insulating qualities.

The shiny layer is quite good at reflecting radiated heat from roof tiles that have sun beating down on them, but these thin foils have never (so far as I know) been accepted as meeting the insulation standards required by Building regulations.

Their Certificate refers to tests where the foil was used between two tested roof structures, which I think will include two (insulating) layers of still air.

most heat loss in buildings is between materials where there is quite a shallow temperature gradient, and the radiated heat element is a very small proportion of the loss.

I don't doubt that they will make some difference, but I very much doubt that it will be anywhere near as effective as 4 inches of mineral wool or 2 inches of closed-cell foam.

Thanks all. Luckily we have a listed buildings advisor at work so he should be able to help.

Whatever we do has to work - I'd rather lose more space than have it too cold.