We are considering post/beam construction, making small, hexagonal/round cabins (posts at the six vertices, which also support the roof, with in-fill that creates a rounded effect).
We are either considering a sloped flat roof, or a reciprocal conical pitched roof.
John Elliott wrote:If you can find it in a big enough diameter, it would probably be great framing. But as you say, it's going to be hard to get a log you can mill into a beam. Some time ago, I had land in central Missouri, and the hedge apple was quite shrubby in character, so much so that it would be hard to find a 6' length you could make a longbow from (which was one of the prime uses for it). On the other hand, there was lots and lots of white oak, and one tree would provide a large number of construction quality beams.
Yeah, I'm familiar with white oak. I don't think I would like to mess with mature trees too much, other than to prune. They are fantastic trees! I got married underneath one last year.
I'm thinking more along the lines of unmilled timber framing, however. Perhaps less mature (2' dia) white oaks that could re-sprout...
I am also considering doing the in-fill as a sort of light-straw wattle & daub. What central Missouri native wood would be good for the wattle? Willow?
Edit: also forgot to ask-- any recommendations for roundwood timber roof beams? For a flat roof? For reciprocal?
There are any number of woods that can be used for wattle depend on the exact location, but many sources for 8 foot whips when growing in shade or streambanks or edges.
Getting poles for a roof is a whole lot harder. You may be able to find some shooting up in shady spots, but getting more than a dozen matching on any piece of property will be a challenge. Cedars are what my friend used (low pitched round living roof with a center pole, timber frame with strawbale infill). It was still tough to get enough the right size to make the span--no way he could have done a reciprocal or free span. He couldn't free span the loft, either so the support pole was not a big deal to him.
I would LOVE a reciprocal roof with a working cupola (controllable light and vent).
I am planning on the basic "cabins" being 300 sq.ft interior, so my spans won't be that large.
However, I just discovered this:
A double-reciprocal roof design!
I will try and hit the highlights (let me know if I have missed anything.)
"Living in the round" is as much a cultural mindset as anything else...simply put, it's not easy and many that think they will like it, soon find they do not. So if you have lived in the round before great!...Proceed with a light, and happy heart...If not...really think about it. Most cultures that live in the round are living nomadic or semi nomadic lives, and/or living in very "big" round space with multiple floors and some flat surfaces. This is not a "right or wrong" concept...just an architecture choice that many choose without really comprehending what they are picking.
Oak, Osage, locust and/or several others (until you get into something like Mesquite) all cut about the same if your tools are of good quality and properly sharpened...so there really is not a big difference in what they do to tools (especially power tools or really sharp good hand tools.) If Locust is a 10 in this group...oak is a 9.5 or better and Osage is in between. Also, timber frames are (for the most part) cut "wet" (or in the "green") and this has a huge effect in how they cut. Oiling, and/or "wetting" your edge and the wood also facilitates cutting and clearing the chips.
If you do choose to proceed "in the round" little exceeds a corbelled or reciprocal roof. I have CADs for both styles, and there are many other "mondala" variations (as you have seen and shared) that are stunning. They can be a little challenging to assemble, and if "truly jointed" much more difficult to layout and cut. I will warn you that just because you see so many DIYers doing these...does not mean they are doing them well or that they are designed and engineer properly. Your space seems small enough that you should have little issue.
If you are working with "round material" (these are called "bolts") you are going to have much more of a challenge in layout and joinery unless you are going for the "really really rough look," in your joints and workmanship. In the size range you have mentioned, you very well may find plenty of Osage that will fulfill your needs...especially in Missouri. If this is your first "full scale project" I strongly recommend more than thorough (and longer than normal) planning, modelling and blue prints both in elevation and plan.
Let me know if I can be of further assistance.
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