Now I've finally moved I'm sorting out my workshop. I now have an outside workshop, which is a brick built double garage. I'm going to dryline it to make it warmer and less damp (also running a dehumidifier full time on the damp front). I intend to screw 2" batons to the walls and then 12mm chipboard sheets fixed to the batons. I had intended to put loft insulation between the brick wall and the chipboard, but have run into a couple of problems. Firstly it only seems to come in 100mm / 4" thick rolls now (not2") and secondly it works out very expensive (I have 70' of wall to cover, and I'm going to 8' high -which is a lot of sqr ft. of insulation).
Does anyone have any suggestions for a more economical insulation to put in there, or failing that how well would just a 2" air gap and the chipboard sheets help to insulate it?