Metal ring for a 20ft yurt

[Yurtman]

Hi Charlie
It’s almost done. Having 2 made, one will be for a 20ft yurt with 2x4 rafters and the other will be for 2x6 rafters for 24ft yurts and perhaps bigger.
A friend is making the prototypes now and I should have them in 3-4 weeks. It’s exciting, I’m keen to see if they flex and hold up. I may offer them for sale if there is interest. I hope to make my prototype 20ft permanent yurt this year if I can find the time.

[Yurts_latvia]

Cool. Be great to see photos once they're up! I guess with those hefty rafters you're all set for thick

insulation

and snow.

[Yurtman]

Can’t believe it’s been a year since I last posted about my metal Ring. It’s been through a few iterations, but I think I’m getting somewhere now.

I hope to raise my first “Permenant Yurt” prototype design this summer. As some of you know, my usual yurts are designed for temporary set up, camping, back yard space, rentals etc. not really for living in, but people do adapt them to live in as the price point compared to permenant yurts is really good.
Because of this interest, I thought I should design my own reasonably priced permenant yurt kit.

I’m not a big fan of the hulking wood Tonos (ring) and the main reason why I designed my super lightweight laminated Tono for my

Camping Yurts

(it’s 8 lbs), so I started designing a metal one. I like simple, sleek, clean, designs and so metal would achieve this.
The first design (Mk1) was a simple 5” circular circular steel strap that 36 square flanges were welded to (see attach photo of it standing up against a post). There would be a slit cut in the ends of the roof rafters so they could slip over these flanges and be bolted in place. We made the ring, but it was not stiff at all and flexed quite a bit, so we shelved that, needing to stiffen it somewhat.

The Mk2 has been made (see photo) and is really stiff. It weighs about 80lbs. I think we can get the weight down further by changing the design again to use thinner metal.
The Mk3 will be lighter, stronger and the roof rafters will interact with the ring differently. With the Mk 2, the rafters are cut at 30 degrees to meet the face of the vertical strap and then bolted. The issue with this is “load” transferred to the rafters, increases sheer and so potentially the rafters could split at the bolt. Because the ring is pushing down while the rafters want to push up. I’m probably over thinking this.
With the MK3, the vertical face of the ring will be 30 degrees and the rafter will be cut at 90 to butt against it, therefore passing load down the length of the rafter which is way better
This description is probably too complicated to visualize with out photos, but it’s not made yet so I don’t have any😀
Anyway, the MK 3 is going to look very similar to the attached photo of the Mk2, but it will be flared out so the rafter butts to it and then bolted. There will be a flat top to it which stiffens the whole thing.
The Mk3 ring will be made in the coming months and I plan to build the yurt this spring/summer, but I have a lot on this year. I’m hosting a Primitive Skills event here in Oregon in May. If you are interested check out the website WhiteRockGathering.com

For the build, I’m going to do a cement pad rather than deck. It will be way cheaper and easier. I thought about passive floor

heating

, but just don’t have the time sadly. I’m not living in this yurt, it will be my show room and summer rental.

The plan is to sell the yurt kit as well as offer the ring to sell the Tono to yurt companies and people who want to build their own yurts. I have some modular ideas about the lattice wall, but I’ll share those later.
I plan on getting this yurt and ring engineered to get sone sort of certification if any one knows an architect or engineer that can do this. I hope to put it all in CAD at sone point.

[Bob Rowlands]

First off, I'm no engineer, so keep that in mind when you read my comments.

1x construction lumber with edge knots-that's dang near all of it- is non structural in load. It is prone to splits when tensioned, flexed, compressed, and twisted. Anchor bolt holes will only weaken it more.

That's why I like the 'sandwich' style ring. 5" wide 3/4" plywood top and bottom with correctly sized 4x4 blocking in between so that 1x fits up into the slot a few inches. Rafters are completely loose in the slots between the spacers.

No holes, no bolts, no hardware. Bounce and bob in the wind. 'Give' yields but no fail from splits down the road with use. I used those for 7 or 8 years with less than great 1x3 rafters and not a one failed. Twist, yes. Fail, nol. No rafters over 8'

The entire ring structurally moves and slips independently and that's it's stongpoint with the skinny little 1x3 rafters that I use. Same happens with a skin on frame or folding kayak. Incredibly strong because of ability to flex, yet light in weight.

Now this is just my opinion. I'd be leery about a big heavy metal yurt ring with solidly bolted rafters flopping up and down in a strong wind. VERY leery. Wood can collapse, but that ring could kill you. With three solid bagana posts and 2x6 rafters I'd have a different viewpoint.

Again jmo ymmv. Good luck Richard.

[Yurtman]

For Roof rafters, I will be using clear Vertical Grain Doug Fir. No knots. It’s really tight grain, beautiful and expensive, but incredibly strong. You are right about knots though
The way big yurts fail under load is often rotation of ring in the horizontal plane rather than just collapsing down or rafter breaking, unless cheaper construction lumber is used. Knots are the weak points then.

My lattice walls will be made from clear straight grain Doug Fir. 1.5”x3/4” way thicker than most yurt manufacturers. I think it will be interesting to see what its rating will be when it’s engineered.

I don’t know what the weight of the big wooden Rings that the big yurt makers weigh, but I think my ring will be the similar or even less.

I’d be curious to know what the experiences are of those who have had a yurt collapse.

[Bob Rowlands]

I had a 14' yurt collapse... from being tossed through the air in a wicked Colorado blizzard. Looked like a WWI bomber crashed in the back yard. Nothing but torn canvas and busted sticks. Eight full days of work gone-from not anchoring the yurt. "Awwww.. it'll never move." hahaha

The plywood ring I described above, survived that without any damage. Or so I recall that was a decade ago though.

[Yurtman]

Yes I have lost a few rental yurts at events to wind. We always tie them down, but we have had some big winds. I’ve split a few rings and broken lattice, but the beauty of a yurt is it’s easily repaired.
Along with ropes over the

camping yurts

, I’ve found that the best way to anchor a yurt in high wind is to tie 3 ropes to the ring equally spaced out, tie them together in the center about 2-2 ft below the ring and then take a single rope and tie it to one of those screw in animal tethers in the ground. It really holds everything down.
Lift is what is created when the wind passes over a yurt. It acts like an airplane wing. The ring and poles lift, poles then fall out and it all goes “pear shaped” from there😀

[Bob Rowlands]

This is completely off topic.

After the first yurt loss I said, "Never again." I had my 16' yurt wall lath ell bracketed solidly to its platform. Plus a bridle holding the roof to the ground, and an internal cable anchoring the ring to the ground. That yurt was anchored solidly.

OK. So the yurt is 50 yards behind our house. I was inside our house when I heard an increasingly loUD ROAR that sure sounded like a plane was about to crash right here on our property. Since we live just east of the Air Force Academy flying field, that isn't an impossibility. Then something hit our roof.

I ran to the back window and looked out to see a massive whirlwind come off the roof, land on the ground and incredibly, make a beeline for the yurt. Sure as hell it went dierectly over the top. The cover instantaneously blew up like a hot air balloon as the tornado passed over. Then it went back to its normal configuration. The tornado passed across the back yard, hopped over the fence and hit the neighbors house. Shingles blew off, the tornado passed over the ridge and I lost sight of it. All the junk flying around inside the whirlwind made its size easily visible.

We lost shingles on our garage roof. The yurt had a few broken rafters and laths, but otherwise OK. That right there is testament to how tough yurts can be, and also to just how good I had it anchored.

Then there's the story about the lightning strike on our house. But that's not yurt so...later.

[Yurtman]

So here is an update to my prototype 20ft permenant yurt with Metal ring design.

The title of this thread is a typo. It’s should say 20ft.

I set up the ring in my workshop with a couple of rafters attached. I was checking the angle of the bolt plates to make sure they were the correct and also get a feel for the space beneath the ring with the idea of a small loft for a bed. The roof angle is 36 degrees, but will probably be 35 with the Mk 4 ring.
I hope to have time this summer to set it up on a deck and make the vinyl cover. I have a lot going on this year, so we’ll see.