The roof can be constructed the same way and many are made with a flowing.
Putting a roof on a cob house.
Many cob homes are made with curves bumps and flowing lines.
You would place a bond beam at the top of the cob wall ideally concrete and rebar or alternatively airplane cable connecting all the members of the roof in one big circle they way the roof is designed is to act in compression while exerting force on the bond beam which will act in tension.
From sod to straw wool to wood there are a variety of roof insulation options for cob houses.
Windows and doors in a cob house.
Basically have a big beefy piece of wood at least 6 inches thick and go for as wide as the wall.
For a first time builder a yurt style roof like cyric30 suggested would probably be easiest.
Learn about the pros and cons of each material in this excerpt taken from roofs.
Abobe cob construction will feature prominently along with alot of old timber my place is named bedrock after the flintstones.
The main approach here is to have a solid timber act as the header for the span of the top of the window or door.
Cob structures can be used as homes chicken coops barns and even smaller ones for ovens.
I m 6 mths into the build todate and am almost ready to do the walls so i cant wait to put into practise what you have shown me.