Windows and Slopes Having built four roundhouses, I am convinced that the pitch of the roof of this Bronze Age home is steeper and the thatch thinner than most archaeologists suppose. Built of wood, mud, and thatch, they generally come through the millennia only as foundations and floor plans, so archaeology offers few definitive clues. At the famous Iron Age reconstruction of Butser Farm, in Hampshire, England, the roundhouse roof is pitched at about 45 degrees. It was done by a professional thatcher, which means it was thatched in a modern way. On my roundhouses, I tied layers of water reeds onto the roofs in the simplest way possible, then added a thatched cap to the top.
Rain runs off the steeper slope quickly before it has a chance to seep through.
They require about one-third less thatch than those at Butser Farm. And they are thin enough to allow smoke from inside to filter through, clearing the air inside. Most archaeologists assume roundhouses had no windows, although I cannot understand why. It seemed reasonable to me to cut windows in the daub walls, not just for light but to provide a draft for the central fire. Windows might be fitted with reed blinds that can be dropped to block the wind and elements.