Roundwood vs Square wood Roof Poles

[Yurts_latvia]

Hello again,

I hope this question hasn't been covered too much before and therefore can help others too...

I'm just making my second 14 foot yurt with roundwood aspen poles, they're about 30mm in average thickness.

I went for roundwood partly because it seemed a lot easier to drill round mortises into the crown. But I've noticed how they twist in the holes, possibly making the crown less-secure, and wonder if square wood and mortises would make everything a bit tighter.

+ I'm curious to forge the tool to burn square mortises into the crown. What would be the correct name for that?

What are the pros and cons of using roundwood vs square wood for rafters?

I've noticed square or rectangular rafters are often elaborately shaped into an octagonal profile which, whilst attractive, must require a lot of work.

My friend tried using rectangular wood and kept the pieces square, it seemed to work ok for her. Is this ok practice too?

I was thinking instead of 30mm roundwood, I could use 18mm x 45mm milled softwood, for a light-duty 14 foot yurt. And thicker pieces for a year-round yurt. Does this sound about right?

Big thanks to anyone who can point me in the right direction with this one!

Charlie

[Yurtman]

You didn’t say if this yurt is permanent or just a temporary structure. This will gave a bearing on square v round.
Square or rectangular will be stronger so if you have to think about snow, go with thicker rectangular.
If the yurt is temporary for camping etc, then round is fine. I like round poles. I don’t see why twisting would be an issue as it’s round!

The easiest way to make the round tip that goes into the ring, is to use a tenoner. Lee Valley Tools has a good selection.

[Bob Rowlands]

18mm x 45mm is a 1x3. My 12', 14', and 16' nomadic yurts all had 1x3 rafters. I weigh 210 lbs and could hang from two adjacent rafters.

[Yurts_latvia]

Thanks so much, Yurtman and Bob! What a service you are providing for newcomers to yurt making

We are in the process of beginning to make yurts for ourselves, with the view to begin marketing them once we have some decent experience. So I will try rectangular roof poles as a comparison with roundwood and see how it goes.

In Paul King's book he mentions that yurt makers in central Asia tend to acknowledge roundwood khana and poles as being stronger than square sawn, so it's interesting to hear different views. My roundwood aspen poles definitely feel like they have a bit of flex in them, but I wonder if this is also partly because they're still drying out.

Cheers for the tips again fellas!

[Bob Rowlands]

1x3 is WAY stronger in load bearing than a round wood pole half that thickness. Proof is there's no way I could hang off of two closet rods that are 1.25" in diameter. I would know about that because I cut and installed many THOUSANDS of 1.25" closet rods in my carpentry career.

Keep in mind that milling wood requires machinery. Trad yurts predate milled wood by a long, long time. The redundancy in laths and rafters make the yurt >>>the best<<< tent by a very wide margin. FAR superior in every respect to any other tent design.

Good luck with your business.

[Yurts_latvia]

Thanks again Bob, I will begin burning my square mortises into my crown today with an iron bar that I pounded into shape!


C

[Bob Rowlands]

Cool! Good luck!