Insulating old (1790s ) house - conflicting opinions

[Jumpy Guy]

I have an end terrace house, built around 1790

It was renovated sometime in the 1960s, when new walls were studded out, and gyproc boarded. Essentially created a box within the existing stone walled room.

I think the main reason for this was to make the rooms squarer; the original walls vary from front to back as much as 10"

At that point they didn't add any insulation, which I want to add now to the two external walls (front, and end terrace side)

So.. I have an original wall, then a cavity, and then 1960s plates and studwork, then gyproc. The cavity varies in depth from about 2" to about 12 "

I've had a couple of builders round, and had varying opinions, which roughly split into two camps-

- vapour barrier, then celtotex, then gyproc (i.e. keep moisture in the house)
- no vapour barrier, rockwool, then gyproc (i.e. allow the walls to breathe, and let moisture move through the wall)

Both suggested keeping the existing studwork line.

Any thoughts ?

[Jumpy Guy]

Thanks, so foil backed celotex sheet insulation ( foil on room side ) and then foil backed gyroc ?

That was another suggested route ..

I wouldnt need separate vapour barrier then ?

[Jumpy Guy]

Ok, so just insulated plasterboard ? Onto the studs?

And did you have celotex behind too? And vapour barrier ?

And apologies for the 20 questions; every time I ask, I get a slightly different answer, which is great, but leads to more questions..

[Jumpy Guy]

This is all useful, if confusing.

One thing i should add; this is ground floor, and there are various air bricks into the void under the floorboards.

I live on the edge of a moor, with europes largest wind farm, so normally it's pretty windy.

As a result, under the floorboards , and the void behind the 1960s stud work has a whistling gale whenever I've investigated.

[Jumpy Guy]

This might sound over simplistic, but could I "half insulate" it, and add a vapour barrier.

By that I mean thinner insulation than I'd like, allowing some heat to escape into the solid wall.

Vapour barrier to prevent moisture.

In practical terms, 2" of celotex rather than 4" ?

I completely understand that no one can tell me it's the 'right' solution....

[Jumpy Guy]

I live in Scotland, on the edge of a moor, so it would always be nice to be a bit warmer...