I've asked similar things before but not yet found the right product.
The workshop is a double garage that's stuck on to the front of the house. I've moved the boiler and DHW cylinder into the back of it and even fitted a radiator. I've insulated all the walls with 2" polystyrene and 18mm plywood; there's 2" polystyrene between the rafters and 1" insulating foam stuck to the door panels. I've managed to seal the top of the doors and, with a bit of ingenuity, the sides are OK but need a little more work (awkward holes where the support arms pivot up).
The gap at the bottom of the doors is a good 10mm, how can I seal it without adding a batten to the floor or door? Are the brush strips any good? Or the rubber "bumps" that can be glued to the floor? or ... ?
Dave