Heatseeker

Thanks very much for the replies. So - drill through timber into brick with 6mm SDS masonry bit. Need to hire a SDS drill. My driver is DeWalt 18V XR - good enough do you think? And these screws....? https://www.screwfix.com/p/easydrive-tx-countersunk-concrete-screws-7-5mm-x-180mm-100-pack/9569h

I have 20mm expanded polystyrene plasterboard dot and dabbed to external brick wall which is dry and has been fine for 15 years. I don't want to remove this, but to add 3 x 2 studwork infilled with celotex and then insulated plasterboard over the timber. How do I fix the 60mm timbers to the existing wall? I can't find any fixing long enough? Thanks.

I want to insulate this room, which is approx 300mm solid stone, mostly external walls. It has what appears to be a cement 'render' in places - probably more to repair the stonework than anything. It is dry and we never had any problems of damp with the previous polystyrene backed plasterboard. Internally, the wall is not flat, with the top falling backwards by about 50mm compared with the bottom. As the room is not large, we do not want to lose any more space than necessary. There are a lot of sockets to bring through the new work. There is a water pipe - could that be run at high level in the deep void? The stone is very soft and mechanically fixing is difficult. I am considering two IWI options. 1. Dot and dab, using 50mm PIR backed 12.5mm plasterboard. This would give an air gap of around 10mm at the bottom and 60mm at the top. That would give a U value of around 0.3. 2. Build stud work, would 50mm timber be sufficient, infill with 50mm PIR - possibly more thickness of PIR towards the top of the wall, then use say 10mm PIR backed plasterboard screwed on top. This would provide a vapour barrier and prevent any bridging? I would be very grateful for any opinions or advice. Thanks.