I am converting my attached garage into a gym space. The three external walls are single leaf brick. with no render or plaster on either side. Garage door has been removed/bricked up and double glazing being put in.
In order to save space, I have decided to go down the treated batten route rather than stud it out. I've been looking at foil-backed insulated PIR board to affix to the battens, as I understand this gives a superior U-value and also has the benefit of acting as a vapour barrier. The question is, how thick does it need to be? Looking at some online calculators, it's suggesting around 75mm would put me into the desirable U-value range, but it's a lot of space to lose. I'm wondering if this would be overkill, and whether I'd get away with 50mm or even 37mm?
Also, I don't mind paying a bit extra for better performance. Any recommendations or advice on newer products would be appreciated, thank you.
In order to save space, I have decided to go down the treated batten route rather than stud it out. I've been looking at foil-backed insulated PIR board to affix to the battens, as I understand this gives a superior U-value and also has the benefit of acting as a vapour barrier. The question is, how thick does it need to be? Looking at some online calculators, it's suggesting around 75mm would put me into the desirable U-value range, but it's a lot of space to lose. I'm wondering if this would be overkill, and whether I'd get away with 50mm or even 37mm?
Also, I don't mind paying a bit extra for better performance. Any recommendations or advice on newer products would be appreciated, thank you.