by richardanthonyj »
Fri Jul 05, 2019 9:51 am
That's actually a tricky one to answer. Is the building Article 4 (a building of interest to the local authority?).
In terms of building regs, you're clear when it comes to "structure" as the stud wall won't be carrying loads from building elements (if it falls down, the building wont collapse). However, you may fall foul of Insulation requirements, which from recollection, is based on the percentage of the overall structure being worked on.
Even if building regs dont apply, putting a stud wall up against an external stone wall without some thought isn't advisable. The new stud will potentially form a cold bridge and lead to condensation in the newly formed cavity. You'll need to at the very least install a vapour barrier and 25 mm breather gap to the rear of the studs. If you're going the whole hog, insulate with PIR between the studs to improve the thermal efficiency in the room.