I have a fairly big 6mx7.5m garage that I want to turn the back part of into a workshop that is going to be comfortable to use in cold weather. It has two old style breezy garage doors, a (mostly) plaster boarded flat ceiling with a vaulted roof over that, it also has a separate door and two windows. But no insulation anywhere to be seen. I've like to insulate the walls and roof to get it to retain heat when I add in a heater when working in there. However, because it is still also going to act as a garage, it needs to still be able to take cars. So, does this plan make sense? Walls: Batten walls with 100mm treated battens, spaced 600mm apart, fill with wool batts (or celotex type boards?) and then seal over with a vapour barrier sheet and finally finish with OSB or ply that I'd then paint to give me a solid surface to attach stuff to in the workshop. If I was to do that, given I'm not going to be insulating or putting down additional damp proofing or insulation on the floor, then how far to the concrete floor should I go? Should the battens go all the way to the floor? Given they are attached to the external cold wall, no harm in also going to the floor? Should I spray the brick wall with damp proof spray first? Roof: Can't decide if I should go warm or cold roof here as I've got a flat rafter ceiling and a peaked rather ceiling only about a meter above that. Given the geometry, it feels a lot easier to again put wool batts in the roof and then a sheet of vapour barrier again followed by OSB or plasterboard again. Or should I go all the way up into the peaked rafters and do the same, but at that level? Floor: Going to just leave as is, but might put down some rubber matting for a bit of warmth and comfort under foot at the workshop end of the garage. Does this make sense? Or any other approaches better? Photos attached. Thanks and appreciate any feedback.