Maybe this is nitpicking, but glacialis usually means characterized by ice, very cold, icy, frozen, ice-like, rather than made of ice. The suffix meaning "made of" is usually -eus, a, um, but there doesn't seem to be any such adjective attested for glacies. So as not to go into longish phrases like domus e glacie facta, personally I think I'd go with snow instead of ice and say domus nivea.
If you want to borrow the word "igloo" into Latin and give it a Latin ending, I guess you can go either way: second-declension iglus, igli (or possibly iglum, igli) or fourth-declension iglus, iglus. The second declension is usually more productive with borrowings, but there can be exceptions. In this case I suppose there could be influence from association with domus.