| Comment | Not an expert on the exact subject but a tradesman, & my dad's an architect. We both have an interest in these things..
Wouldn't surprise me if they add a foot to the thickness of the external walls, to be honest. And that would almost certainly be on the inside.
A half of that would probably be the insulation, but you have to have a void between your bare sandstone and your internal insulation, otherwise you get all sorts of problems with damp. So then you have to whack off the (probably) original lath & plaster internal wall (note, still only talking about the inside of the actual sandstone external wall, not walls between rooms or between flats which are handled differently). Then you probably would strap it with something designed to maintain a cavity, like a mesh or a frame of some sort, then build stud walls inside that with their own double layer (6-8 inch) of insulation and then double layer of plasterboard.
That's how you would do it with the current technology, anyway.
Internal walls are slightly easier because they don't need a cavity, although there often is one between flats, anyway. |
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