DavidKilburn

This hopefully will be a straight forward answer to you guys in the know... hopefully! I have an old stone build (stone and rubble) farm house, with concrete floors. We are planning on UFH with air source. We're planning on 100mmpir on the concrete, membrane, then pipes and screed, raising all door heights to take account of the new 150mm (100mm pir and 50mm screed) higher floor level. But, we plan to stud out some of the externally facing walls - building an internal stud frame and insulating between the studs (100mm pir), before new plasterboard and then skimmed. Question #1 is... do I stud first, to the plasterboard stage, then insulate the floor, pipe and screed, or... do I insulate to the existing walls, pipe and screed, and then erect the stud work on top of the screeded floor, remembering to leave the pipe work away from the edges to take account of the new internal walls? I'm guessing stud first, but I'm no expert! Any advice appreciated. Question #2 is... All but one floor is concrete - the only other ground level floor is a suspended timber floor, with joists. Don't ask me why they did all but one... I have no clue! We want a consistent floor level throughout the ground floor, so will need to bring the suspended floor up to the same height. We plan on again using 100mm pir, but that leaves 50mm (which would have been screeded in the remainder of the property). If I go with a wooden board clip-in system for this one room, how best to make up the 50mm?? If the board system where the pipes are placed is 20mm say, and the whole floor is then covered with 9mm ply, (20-9 = 29) that leaves me with 21mm to pad out to get me to the overall uniform level of 50mm? Do I go for 120mm pir, or Do I go for a 20mm board below the PIR to make up the difference?? Thanks in advance!

@saveasteading Thanks for the swift response. I take your point re - if it gets hard to chip off, it's probably sound - so I'll leave where it is! Not sure about the stone - in the final throws of legal negotiations before getting the keys. From the looks of things it's dressed, and well pointed (not sure what with). The external walls are hefty, certainly between 300-500mm deep and sound. Footings I'm not sure about - survey will tell is that hopefully. The place is at least 250 years old - the attached barn dating back 400 years maybe. Not a crack in sight, the windows and door apertures are square and true (well as good as they were in the 1800s), no cracked glass, and the sash windows still run smooth. The property is on the Lancashire/Yorkshire border, so if its a vernacular construction it will be either Yorkshire sandstone or possibly a grey limestone, but not a limestone you'd find say in the Lakes. My money is on a hard yorkshire sandstone - it's not grey like a granite, more a yellow / pain colour. It's in an exposed location though and will get plenty of weather - rain and wind. Again, I think we're prepared for the trade off in room size, but we'll have to see just how much we lose. A warm slightly smaller room has got to trump a slightly larger cold one right?

All, I'm starting to renovate a farmhouse in the UK. The external walls are solid stone - no cavity. The downstairs walls are also solid, upstairs are lathe and plaster, as are all ceilings. No damp as such, but it's been empty a while, and just cold. There is absolutely no chance of externally insulating the property, so internally insulating with stud boxes in each rooms, well insulated with PIR, vapour barriers, non-ventilated air and service voids etc. etc., and then a PB layer with a coat of plaster on top; kind of like a box within a box approach. I know I'll lose room space / dimensions, but it will be worth it for a warm insulated house. Question is, all the external walls, and the internals downstairs which are stone, have a thick cement/plaster (could be lime but I'm not sure) skim on them, of varying quality. Some is sound, other parts crumbling away and very dry. Do I strip the lot off, and go back to stone and start over - allowing the stone to breathe, or does it matter if I just build my box in a box and leave the good skim where it is on the stone work and stud over it? Obviously I'll remove the loose / crumbling stuff. My thinking is take the lot off, but that's a big job, not to mention filthy work, but I think it will be worth it - if it's necessary. It must weigh a tonne too!# Thoughts?

Hi all, just joined this forum - and this is my first post! Very interested in @jayc89 and what was said re electrical void. I'm renovating an old farm house - solid stone walls, no cavity. I'm planning on building a box in a box, studding out with 3x2 (not against the wall, but with 10-20mm air gap. Then going 60mm PIR foil-backed between the studs at 400 centres, and air tight fitted with Gapotape, and then foil taped over the whole lot to create a silver box. Then was planning on a 38mm vertical stud over the new studs to create an electric / service void. Thanks @ProDave for the info on a gap at 450 and 1150 for horizonal cable runs. I'm guessing a 38mm 'secondary' bottom plate where the walls meets the floor would be okay too? But, the question is, will the 12mm PB be okay without horizonal fixings - just vertical ones - any chance of cracking at the joints?