According to Guide to Iceland, the properties were "built by stacking flat stones to create the foundation, using birch or driftwood to create frames, then covering the structure with several layers of turf."
A small wooden door would mark the entrance and there were "occasionally small windows", although very few were made of glass, since this was, at the time, a rare commodity.
"On the roof, there would usually be a small hole for ventilation, which could be closed in bad weather" thanks to a lid "made of animal guts" stretched over a barrel ring.