When i built my workshop I thought I would be really flash and incorporated a wash room and toilet. After a couple of winters i got fed up with burst pipes and ripped the lot out.looks a really nice space in there even with the cladding on the ceiling makes it nice and bright
a couple of things id rather tell you about
if theres a fire small deal with it if its got anywhere near the roof dont go in there that plastic can drip onto you and burn you
beaware that that radiator and pipes can still burst in freezing weather that garage is the coldest part and can be calling for heat via the rad frost stat and wont get any as the house stat says no or your on a timer so boiler wont come on
this is the point where the rad can freeze and so can the pipes this is where you have to decide between a flood in the garage or drain the pipes and radiator
i gather you havent heard of parafin heater or oil heater in the outside toilet as without it they burst for funWhen i built my workshop I thought I would be really flash and incorporated a wash room and toilet. After a couple of winters i got fed up with burst pipes and ripped the lot out.
Did try an old type upright paraffin heater but the stink always made me feel ill . Nothing else about that I could afford in those days ( 70's).i gather you havent heard of parafin heater or oil heater in the outside toilet as without it they burst for fun
a little ozirt oil burner is ample enough to be used for an outside toilet and plenty of air changes in there and it will keep it nice and warm