I have an equally cold garage open fronted and facing north east, the planners insisted we had a mono pitch roof to match our neighbours even though theirs is the other side of the garden wall. Due to the garden wall being about sixteen feet high on our side (22 feet the other side!) I have a good sized loft above, however on the ground floor there is only seven feet of headroom.On the point of steel corroding more quickly in a warm garage than outside. My garage has some form of supercooling effect unknown to modern science, even when the mercury has withdrawn to spend the winter months hibernating in its bulb, I have to come outside into the frosty landscape to warm up.
I tried putting a heater in but science was mystified again as even though it blew hot in the workshop, no more than ten yards away , it had no impact in the garage.
Cryogenics for the inquisitive & an ideal spot for superconductivity research.
M