Step 10: Build the Roof
Build the roof after the bond beam is finished. Any type of roof is possible, and space doesn’t allow a lengthy discussion. We used a metal compression ring with radiating wood poles covered in thatch. Create large roof overhangs of approximately 30”-36” to protect walls from moisture damage. The exact size will depend on your climate.
The roundhouse has a super strong feeling due to the concrete bond beam, thick walls, sturdy poles and round shape. You could probably have a dozen workers on the roof with no visible effect. The roof frame went together almost like clockwork. The compression ring worked perfectly. The roof was all bolted together in about 4 hours, in part because the poles were precut and prefinished in advance.
Thatching is usually very slow and laborious, but we thatched our roundhouse in just one day and for only $100 using pre-made thatch panels. That's why I love thatch panels - they're very inexpensive and all the tedious work has already been done. And they work great on round (conical) and organic shaped roofs because they're flexible. Just bend them into position and nail in place. We installed the panels using 8" spacing. Plan on rethatching every 3-5 years or so, depending on the quality of your thatch. Some thatch will last 10 years or even longer.
In cold climates you’ll want a thick roof with lots of insulation. This can be achieved with trusses or TJIs (engineered truss joists). Wide dimension lumber could also be used, however, this requires cutting old growth forest.