There is a book by Rob Roy called The Sauna that gave me a great idea. He is probably the most well known popularizer of cordwood masonry construction, and in the book he describes how he built a round cordwood masonry sauna (about 12 foot diameter) with a relatively flat sod roof. I had recently admired adobe buildings with flat roofs supported by "vegas", or log beams, so this was nearly identical in appearance. I already have a lot of poplar logs that I can use for this, and poplar is actually a good wood type to use. I was thinking that instead of mortar I could try to use cob. The loess soil here is very hydrophobic when it dries, so I wonder if it wouldn't be suited to the purpose. I already plan to build a shed first, as a sort of proof of concept before actually building a sauna. All in good time.
I had always thought that cordwood masonry looked ugly - like the bastard child of a brick house and a log cabin. But now I think that it is a very flexible building method that can accomodate a wide range of plans. In addition, what has been called "cobwood" makes it look even more attractive, as the concrete portion of the wall is replaced by cob, reducing the embodied energy in the wall (see more about this alternative in Rob Roy's book Cordwood Building). As far as I can tell, cob is indistinguishable from daub, as in "wattle and daub". I don't know enough yet about its structural properties.
A cordwood masonry building can be round, which is a beautiful thing. It could have a reciprocal frame roof, also a beautiful roof. But I will build a rectangular shed with a 1:12 pitch shed roof, as rectangular buildings provide the best use of space. Maybe later a round building.
Youtube user Tony Wrench, author of Building a Low Impact Roundhouse.
Build Your Own Earth Oven - someday it would be fun.