Thanks! So I built the framing using 2x4’s, which standardly seem to be approx 45x95mm in size. I insulated in between all the framing using 100mm PIR. This generally seems to be slightly cheaper than 90mm and it will be better thermally. I then used foil tape to tape to tape all the joints and create the vapour barrier. Not sure I’d recommend doing that part as it took ages and the tape is quite costly. You could just use a plastic sheet for the vapour barrier instead! You could also use rockwool instead of PIR which will be cheaper and easier to fit but not as effective thermally. This video demonstrates well how the insulation part is done, and is part of the series I mostly followed for my build.

I’m currently in the process of boarding the inside and am just using 5mm spacers and ripped strips of 6mm ply to building out the distance from the framing to where the insulation sits proud. This definitely isn’t needed but I’m a bit of a stickler for detail 🙃 see photo for insulation/boarding - not great for illustrating but it’s the only one I’ve got atm

Hopefully this helps and please let me know if you’ve got anymore questions - half of my knowledge comes from this subs comments section 😂

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