There are quite a few all stone building from the dark ages made entirely from stone. Nothing but stone. Not even mortar, I think. They look very similar to modern buildings. If you moved into one today, it wouldn't be a lot less comfortable than it was then.

Byzantine & later Turkish architecture used brick domes and arches as roofing in buildings that are still in good condition. If you stand on the roof, it feels more like a hill than a building.