Insulating frame work against old stone wall - best route

[strath44]

Hey folks, we have just got a new to us house, a solid project! Built Circa 1880 but reworked late 1990s

We are starting with the bedroom, as we need to move in sooner rather than later.

The walls are very thick sandstone, with later stud work internally forming new walls using 50mm square uprights and 9mm maybe thinner plasterboard.

We are coming from a very damp house and in the new house I was very happy to feel very good air circulation between the frame work and the old walls from air bricks which I want to maintain! However there is a total lack of insulation.

My plan is:

1 to strip all the plasterboard
2 add some horizontal dwangs / studs for strength to current framework
3 insulate between studs etc with kingspan
4 fit a vapour barrier
5 fit new plasterboard 12.5 mm

not quiet sure what thickness of kingspan to go for, is 30mm sufficient?

is kingspan the best material?

whats best to use as the vapour barrier?

any help would be much appreciated!

We removed a bad built in cupboard which exposed one wall as seen.............

Edited by strath44 on Sunday 21st December 20:29

[strath44]

thanks for the replies so far, I was hoping to keep the existing studwork. Thanks I'll check out the foil back plasterboard.

[strath44]

thanks for the replies folks,

there seems to be some uncertainty about 50 v 100mm insulation.

Is it that 100mm fibre typre non rigid is required or 50mm iS required in PIR type?

[strath44]

thanks for that mike, I will go that route. I have put an order into jewsons.

I am starting to learn more about vapour barrier, which appears to be polythene going buy what jewsons have supplied (I asked for gyproc to kingspan VB).

Some people on other sites suggest that VB isnt required as the kingspan is foil backed, however at the moment I still plan to fit it as the studs will need covered inbetween the kingspan.

I was going to get the room plastered afterwards my worry is where does the warm air or more particularly its moisture go if it can no longer pass through the wall?

The house has approx 5 year old pvc double glazing. Currently there are air vents fitted above the doors into the hall should I get rid of them?

[strath44]

hmm and thats my big worry, our current has massive problems with condensation