Quick DIY Yurt for Cold Climate by Wheaton Labs Standards

My phone currently isn't speaking with my laptop, so I have to post directly from the phone...

A selvedge (along the factory woven edge of the fabric) will not fray, but will likely want reinforcement for attachments. The square sewn on and cross-stitched with an "X" is typical for commercial canvas.

Cut ends of fabric will definitely want a hem to avoid fraying.

I would advise taking the sewn-up roof with the last seam undone, putting it on the frame, and seeing how much more it wants with the edges adjusted for proper overhang. Measure at top and bottom as they will likely be different. You really do not want extra width especially at the bottom as that will allow sagging right where water might want to pond. Extra width at the top would pretty much just be sloppy and maybe allow flapping.

Jay Angler wrote:I agree with Richard - I've had too many grommets fail. However, notice he used the term "hem" so that suggests he recommends folding over the fabric at the edges.

I do have a large canvas tarp recently purchased and strung up over my outdoor kitchen that uses something like this for the tie down points, with grommets mounted inside nylon webbing attached to the edges with reinforcement, giving the option to use either. I do have some nylon webbing to work with, but have gone out of my way to avoid synthetics so far, successful with the exception of the thread, only then because I exhausted all other reasonable options. Would sewing an extra patch of canvas on both sides of an area to receive each grommet be pretty solid? How about some way to sew straps out of canvas taken from the bolt? Anchoring in short bits of my 1/4" manilla hemp to provide tie off loops?

Coydon Wallham wrote:How about some way to sew straps out of canvas taken from the bolt? Anchoring in short bits of my 1/4" manilla hemp to provide tie off loops?

You can absolutely take strips of canvas and sew them into straps instead of using nylon webbing. Just don't underestimate how much material this would take, as I would fold it into thirds and have a half inch to press under so the outside bit won't fray and so it would be strong enough that it won't stretch.

How wide of webbing did they recommend?

There may be a good way to anchor in the manilla hemp, but my gut feeling is that it would be harder to not have it fail than to make the canvas loops.

Jay Angler wrote:

Coydon Wallham wrote:How about some way to sew straps out of canvas taken from the bolt? Anchoring in short bits of my 1/4" manilla hemp to provide tie off loops?

You can absolutely take strips of canvas and sew them into straps instead of using nylon webbing. Just don't underestimate how much material this would take, as I would fold it into thirds and have a half inch to press under so the outside bit won't fray and so it would be strong enough that it won't stretch.

How wide of webbing did they recommend?

He didn't specify for the fabric securing webbing, but made reference to his securing strap that surrounds the top of the wall to help hold the rafters in position. It is 1".

So to make a decent one from the canvas that comes out 1", cut a strip 3" wide, fold and press 1/2" at the edges, then fold the remaining 2" strip 1/2" from each edge again so that the two 1/2" doubled sections meet in the back? Would one stitch in the center of each side be enough? A box-and-x stitched at the anchor point of the loop?

Sorry Coydon, I just can't figure out exactly what you're doing with these 1" "straps". My friend's yurt, the rafters were held because they sat in the gully formed by the zigzag of the wall sections. They had a wire rope that went around the circumference of top of the wall to stop the walls from going outward - is the 1" strap an alternative to the wire rope? I'd have to go and look, but they might have had a second wire rope that went through a hole in the end of each rafter.

With the folds - I'd only press one edge because the other is tucked under. The thickness of the material matters, particularly if it has to fit through some sort of fastener. I'd take a scrap and experiment until you find a series of pressed folds that seem to fit, but yes, the goal is to have the stitching (usually a double row of straight stitching) through all the layers near the center, but about 1/4" apart.

I'm still working on ways to fasten the cover (roof/wall) to the frame and to the ground. The straps were recommended instead of grommets for any place that could have high stress from shrinking and wind, particularly the ends of walls. These 'strap loops' would have rope fed through them to be tied to the frame (or staked to the ground for the roof). So I am thinking the straps would just be anchored to opposite sides of the fabric, and would loop, with 1/2 to an inch of excess, past the edge of the fabric.

Okay, so no need to fold both edges under when making the canvas strap. But how does the outer flap with the folded edge run? For 1" 'strap' would there be 3 1/2" total fabric so that the outer back layer would go all the way and have 1/2" left over to fold under? Stitching would have to be off centre then. If it were 3" total I could fold that flap at 2/3 with the extra 1/3" in the centre to stitch there, but then the strap would be lacking a third layer on one side and have 4 layers in the centre, seems awkward...

Coydon Wallham wrote: So to make a decent one from the canvas that comes out 1", cut a strip 3" wide, fold and press 1/2" at the edges, then fold the remaining 2" strip 1/2" from each edge again so that the two 1/2" doubled sections meet in the back? Would one stitch in the center of each side be enough?

These 'strap loops' would have rope fed through them to be tied to the frame (or staked to the ground for the roof). So I am thinking the straps would just be anchored to opposite sides of the fabric, and would loop, with 1/2 to an inch of excess, past the edge of the fabric.

Okay, so no need to fold both edges under when making the canvas strap. But how does the outer flap with the folded edge run? For 1" 'strap' would there be 3 1/2" total fabric so that the outer back layer would go all the way and have 1/2" left over to fold under? Stitching would have to be off centre then. If it were 3" total I could fold that flap at 2/3 with the extra 1/3" in the centre to stitch there, but then the strap would be lacking a third layer on one side and have 4 layers in the centre, seems awkward...

You have just identified the major problem in the concept of sewing strapping out of flat material. It's like sewing jeans where most of the fabric is only one layer thick, but as soon as you lap over a seam allowance and the front and back, you're suddenly sewing through 3 layers, and when you go to make the hem.... yep, 3 layers times 3 is 9 layers and my machine can't cope!  However, even though the stitching of the hem is 3 layers, most of the bottom of the hem is still only 1 folded layer at the edge, which wears through on Hubby's jeans all the time... Good thing they're farm jeans so I don't care if the fix for that is a bit ugly. In fact, if you've got holey jeans or a thrift shop around, upcycling old jeans for this job could work.

You mentioned having 1/4" hemp rope - you could consider flat braiding it like this video: https://youtu.be/F5Fj6_3XgYE  Attaching a single bit of rope and not having it pull through is hard - attaching a flat braid would be easier. However, you still need some way of "finishing the ends" which can't simply be a big, bulky knot. It might work to sandwich it between the big tarp and a small square of tarp material and sew through both layers in the "square and cross" design you've already planned on.  Same as with the fabric strap, it's *very* easy to end up with too many layers to easily sew through, but the only thing I can suggest is to experiment with a couple of different materials and options and choose whatever seems to a) work, b) be time effective and c) is cost effective. B and C could be trade-offs, but A is required! You don't want this failing in a storm!

If you want to stick with a natural material and have lots of time on your hands... you could learn this sort of strap weaving: https://permies.com/wiki/148217/pep-textiles/small-loom-PEP-BB-textile  Basically, a very simple loom and use something like the tablet weaving cards, and do a locking hand stitch each time you start and finish the length needed for a single strap, leave a tiny gap using a bit of flat stick, and go on to the next strap.  This could be done with thinner material than the 1/4" rope which would make it easier to sew on. The thinner the material, the longer the weaving part takes, and don't try doing it with antique silk cord like I did! (The results were lovely, but that stuff was slippery to work with!!!)

The roof section is joined, hemmed, grommetted, and looped. I used nylon webbing for the outer tie downs since I didn't have time for anything with assurances of holding against a heavy pull. The upper flaps have grommets since they shouldn't really have any forces against them.

I asked for advice on doing the nylon straps but my question was confusing. I ended up sandwiching the canvas between the ends of the webbing and making something that looks like an X in a box. Putting both ends of the strap on the inside would have looked better and been more efficient on material to give a useful loop, but I only used it for utilitarian purposes and it seems to me this will be significantly stronger. No idea how much stress it will actually see but looking to increase my margin for error at this point.

To sew the walls, I'm thinking I will hem the top edge with a single fold, just big enough to fit a row of grommets. The wall is primarily held by a rope in the middle and force from straps on the ends, and the grommets will just have to hold the top in place. It is a salvedge edge so I won't fold it twice to enclose it like I did with the cut edges on the roof.

I'll need 3 or 4 loops on the short ends to secure the wall. Again, I could hide the nylon as much as possible by having it all on one side, but these will see the greatest forces with shrinkage likely to occur, so will do the same as the roof bottom unless there is some expert advice otherwise...

Pushing to complete this for winter last fall, I got the wall canvas done and up. Turned out the roof cone didn't come down far enough for a rope to secure it to the wall. I had the points formed by the longer edges at the bottom of the cone staked to the ground, but they pulled out often and even without them the higher parts formed by the short seams let drafts in.

Still, I started to build a platform next to the current placement and plan out a RMH within that space. I had the platform 95% done and the skeleton of the RMH laid out when the ground took on a frozen state for the season and I could no longer level off the pallets or use the dirt to pack a mass around the bench area. I zipped everything up in a numb hurry and took off for bootcamp.

I arrived back here in April to a partially collapsed yurt. The snow load had been too much for the thin lath of the walls and it all snapped off at the second joint from the top around the entire circumference. Having solid door frames and the wall canvas secured to them retained structure on the rest of the wall, providing some support for the falling roof. Of the 39 uni rafters, only one snapped where there was a knot. The ring and the cone are still up to provide a functional shelter beneath.

I've now recut the wall lath, using 1/2" rather than the 5/16" I'd done following the bunk website. One more coat of tung oil and I'm ready to assemble.

However, I found a problem with the manilla hemp I was using to tie off the lath previously. After the first winter, I had to tear apart many wall pieces to replace the broken ones. All the rope in the joints had stretched, not sure if the fibers themselves stretched or the knots drew tighter as they were stressed, but the lath was not held tight to itself. I tied tight knots in the new pieces and redid nearby ones, but it took more time than even the original assembly so i only did a portion. This looseness between pieces seems likely to have contributed to the breaking of the wall as it was already sagging in odd ways before I left it this winter.

For the new wall I was considering giving up another aspect of natural materials in favor of recent convention since I had good evidence of potential problems. I bought some polyester, diamond braid rope as I read that it: A ties good knots with little if any stretch; and B is UV resistant without the extra treatment something like polypro needs so less likely to break down and leave microplastics around.

It has also occured to me another option I had seen somewhere- using hardware. I'd rather have metal bits than plastic bits. I'm guessing cost is 5 to 10 times more than the rope, but not that big of an investment all things consisdered. These questions remain- useability, durability and availability?

The big one: will hardware hold the walls too tight, do they need some flex to curve and/or deal with weight loads?

I looked at Amazon and a local big box store and haven't found exactly what I'd want. I'm thinking carriage bolts would be ideal only needing to worry about one side when tightening and having a smooth round side for under the fabric. Would I need a washer under the nut? The wall would rarely be moved so not thinking working itself free is a problem. I'd expect temperature differences at the wall would be big enough in winter to cause condensation, would zinc bolts rust pretty quick there?

Coydon Wallham wrote:It has also occurred to me another option I had seen somewhere- using hardware. I'd rather have metal bits than plastic bits. I'm guessing cost is 5 to 10 times more than the rope, but not that big of an investment all things considered. These questions remain- usability, durability and availability?

The big one: will hardware hold the walls too tight, do they need some flex to curve and/or deal with weight loads?

I was wondering the same thing when reading about the hemp getting loose, so it's not a bad thing to consider. In my climate the answer would be easy - Stainless steel with a locking nut. Yes, expensive. Yes, lasts forever. Yes, that means if something breaks or rots, you can replace it. I'd use round head Robertson (square drive) with the head on the outside.

But then again, I've never built one of these, and I'm biased...

Jay Angler wrote:I was wondering the same thing when reading about the hemp getting loose, so it's not a bad thing to consider. In my climate the answer would be easy - Stainless steel with a locking nut. Yes, expensive. Yes, lasts forever. Yes, that means if something breaks or rots, you can replace it. I'd use round head Robertson (square drive) with the head on the outside.

As far as I can tell square drives are only available in screws and I don't want to deal with the inside of the yurt acting like an iron maiden waiting to clamp down on a victim. The other bolts I'm seeing are normal hex heads which are a bit more expensive and less convenient, and "furniture" flat heads with internal (hex?) drives- much more expensive.

One thing is the holes are all drilled out to 7/32" to hold 3/16" rope. I'm not seeing 3/16" bolts in common places, at least not stainless, so to avoid paying a premium to a speciality fastener place I'm guessing I'd have to redrill everything out to 9/32" for 1/4 bolts. (Or with bolts would I match the hardware at 1/4"?) Looks like those would be around US$.30 each in stainless carriage bolts. US$.08 each in zinc, but if they rust that would be a big labour cost tacked on to replace.

Coydon Wallham wrote:
As far as I can tell square drives are only available in screws and I don't want to deal with the inside of the yurt acting like an iron maiden waiting to clamp down on a victim. The other bolts I'm seeing are normal hex heads which are a bit more expensive and less convenient, and "furniture" flat heads with internal (hex?) drives- much more expensive.

One thing is the holes are all drilled out to 7/32" to hold 3/16" rope. I'm not seeing 3/16" bolts in common places, at least not stainless, so to avoid paying a premium to a speciality fastener place I'm guessing I'd have to redrill everything out to 9/32" for 1/4 bolts. (Or with bolts would I match the hardware at 1/4"?) Looks like those would be around US$.30 each in stainless carriage bolts. US$.08 each in zinc, but if they rust that would be a big labour cost tacked on to replace.

I think I understand that with a lattice like you're building, the connector should allow both pieces of wood to slide on the fastener, which a carriage bolt won't do. Since you don't plan on moving this much, that may not be an issue.
No, you absolutely don't want to use "screws" - the type with the pointy ends would be yucky in a yurt!

Isn't 7/32 very close to #10 machine screws (which are actually bolts just to confuse twerps like me)? Can you estimate how long you need them to be? If you have to accept Philips drive, that's life - here in Canada square drives or "Robertson" as we call them, are much easier to come by. I was once told that in the US, those drives were call "crowbar fasteners" because the only way to remove them was with a crowbar! In comparison, my sister gave my 3 year old son a set of Robertson (they come in 4 sizes) stubby screwdrivers for Christmas. My husband was jealous!  My sister thought it was a colourful, useful, cheap gift!

Hubby suggested Chicago bolts - nice and smooth on both sides, but probably even pricier.

Hardware is expensive and you're going to need a lot of it. It amazes me sometimes, how much of our budget for a project ends up in the hardware, but our time is worth it also, so in many situations, we do the best we can. Moving up to a larger hole could be a problem if it makes the wood weaker. The material you used stretched, but is there some way to put a spacer under the knot to tighten it back up again? Or what about using bent wire - a large version of a hair pin or cotter pin of sorts instead of rope?

Even at Wheaton Labs, they occasionally compromise with artificial material - like their plastic wheelie bins for the willow feeders - because it really is the most reliable option. Sometimes perfection is the enemy of the best you can do.

Jay Angler wrote:I think I understand that with a lattice like you're building, the connector should allow both pieces of wood to slide on the fastener, which a carriage bolt won't do. Since you don't plan on moving this much, that may not be an issue.
No, you absolutely don't want to use "screws" - the type with the pointy ends would be yucky in a yurt!

Isn't 7/32 very close to #10 machine screws (which are actually bolts just to confuse twerps like me)? Can you estimate how long you need them to be? If you have to accept Philips drive, that's life - here in Canada square drives or "Robertson" as we call them, are much easier to come by. I was once told that in the US, those drives were call "crowbar fasteners" because the only way to remove them was with a crowbar! In comparison, my sister gave my 3 year old son a set of Robertson (they come in 4 sizes) stubby screwdrivers for Christmas. My husband was jealous!  My sister thought it was a colourful, useful, cheap gift!

Hubby suggested Chicago bolts - nice and smooth on both sides, but probably even pricier.

Hardware is expensive and you're going to need a lot of it. It amazes me sometimes, how much of our budget for a project ends up in the hardware, but our time is worth it also, so in many situations, we do the best we can. Moving up to a larger hole could be a problem if it makes the wood weaker. The material you used stretched, but is there some way to put a spacer under the knot to tighten it back up again? Or what about using bent wire - a large version of a hair pin or cotter pin of sorts instead of rope?

Even at Wheaton Labs, they occasionally compromise with artificial material - like their plastic wheelie bins for the willow feeders - because it really is the most reliable option. Sometimes perfection is the enemy of the best you can do.

The wall lattice does need to move, but a carriage bolt would allow this. The lattice is 1/2" thick so plenty of wood for the square shoulder of the bolt to dig in. This would automatically tighten that side of the bolt as the nut is worked on the other side meaning the use of one tool instead of two, so carriage bolts would be much preferred over a regular nut/bolt combo.

The lath is 1.5" wide and .5" thick, I don't thing the variation in hole sizes being discussed affects the strength of anything. Just seems to me the smaller the hardware the less expensive it is likely to be as long as they are common sizes. I can't imagine enough stress on any one joint that any of these sizes would see stress to threaten failure. Chicago bolts occurred to me, but being less common and using more material I'm guessing the cost would be much higher.

But I had closed myself off to some options assuming specialty fastener places would mean higher costs. I've been spending way too much time looking for stuff on line lately but this time it seems to have paid off- I found a specialty fastener place on line that not only beats Amazon and the local big boxes in price and selection, but has an excellent interface: https://www.boltdepot.com/Browse.aspx?Units=US&Category=Machine_screws&Subcategory=Machine_screws&F_Material=Stainless_steel&F_Grade=18--8&F_Diameter=%2310&F_Length=1--1%2f4%22

Looking through their offerings I've found 2 options that would be a third of the price of the carriage bolts I picked up from the big box. They have 1/4" carriage bolts that are galvanized and by far the least expensive at $.10 per bolt. With these I would have to redrill like I was planning to with the big box ones, but wouldn't have to use an extra tool in assembly. From what I recall, the problem Paul has with galvanized is related to use around fire in the RMHs, it doesn't present a hazard at normal ambient temps, does it?

The other option would be Phillips truss head machine "screws". (I think we need to take up the battle to call these "stove bolts", seems a kinda permies thing to do...) They are stainless steel and #10 diameter, so could put them in with out further drilling, but having to hold a phillip head screw on the other side while driving the nut on seems much futzier than the carriage bolt.

Any reference points for how 'hot dipped galvanized steel' does in environments exposed to humidity and occasional condensation? The same reference sources I see calling it excellent water proofing also mention that zinc coating does a good job, I could use a sense of relative performance among those...

How tight do you have to get them?  Can you reach both ends of the bolt at the same time with one person's arms?  

You can hold a Phillips head screw with one thumb while screwing on the nut and get it finger tight.  Then you hold the nut with your fingers and turn the screw with a screwdriver to get it modestly tight.  Maybe plenty tight for a yurt lattice?  Assuming you can reach both sides, I don't think tightening is that much of an issue....

There's not a problem accessing both sides for assembly, it is a workflow thing. With carriage bolts i should be able to lay out the lattice with carriage bolts through the holes  facing up, then go bolt to bolt with a nut and drive them on in quick succession. A bolt with a driver head would mean propping up the lattice at each point and locating the slots with a screwdriver before doing the nut each time. For 256 joints, that sounds like a considerable pain.

Any idea how galvanized steel compares to stainless/ zinc for bolts?

Coydon Wallham wrote: Any idea how galvanized steel compares to stainless/ zinc for bolts?

I would always use stainless bolts with stainless nuts, and zinc plated bolts with zinc plated nuts.

The yurt is technically "indoor" so zinc plated should be adequate for most things, however yurts don't have overhangs, so I imagine the walls will tend to be higher humidity than typical house walls that ideally have some roof overhang. If you've made sure that the grading slopes away from all the walls and that you install drainage so that things dry quickly, that will help. You may find that one direction shows issues because of typical wind direction, but then you could just replace the high risk ones.

Where some of the concern is that zinc as a mineral is always found with lead as a companion. So when they say that something's "zinc plated", it also contains lead. You're not planning to eat off your walls! Or hopefully, not planning to suck on your bolts! However, more and more of things like nuts and bolts are being manufactured in places with less stringent oversight, so the level of lead can vary considerably. I thought we'd figured this sort of stuff out a hundred years ago, but we discovered that our Corel dishes with a mustard yellow pattern on them, tested high for lead, and they were from the 1980's. However, I *do* eat off my plates, so we now have plain white ones.

I don't know how you feel about silicon grease, but dipping the zinc plated bolts in some grease would add another layer of protection - more time though!

Testing things out today, I found that the 1 1/4" long carriage bolts don't work well because, with a washer under the nut, there aren't enough threads exposed to grab the nut until the shoulders are pulled into the wood. Once assembled, the carriage bolt held while allowing the two lath pieces to rotate. However, after a number of rotations, the nut would work itself loose. This brought to mind a second benefit of the carriage bolt- once the yurt is up and the wall canvas in place, there would be no way to get a driver on the head to hold the bolt if it the nut needed tightening. But maybe a regular bolt would turn with the lath and the nut would not work free like it does with the carriage bolt locked in place? To move forward here I will be using nyloc nuts so they will not fall off entirely and know I am able to go around and tighten them easily while assembled if desired. It would be nice if another lock nut design not involving plastic worked for this instance, but the all metal designs that seem to perform the same function priced out at 10x a normal nut vs. the 3x of nyloc, not a premium I'm going to pay on something experimental on my primary build.

There is "thread locking compound" you can get but it's likely icky

Or you can put two nuts on and counter tighten them to jam them against each other.

Mike Haasl wrote:There is "thread locking compound" you can get but it's likely icky

I call that icky stuff Nail Polish. It comes in a convenient jar with a little brush. I scored several jars from a friend who decided the colour wasn't "right". (why buy new if you can upcycle?)

Or you can put two nuts on and counter tighten them to jam them against each other.

We have some specific nuts called "jam" nuts that are a bit thinner than regular nuts. I wouldn't be keen on nylocs with carriage bolts as they need a lot more torque to screw on, so I only use them when I can access both sides with a tool. This is why we use the "2 nut jam system" on our chicken shelter perches, rather than a nyloc. We use plenty of nylocs elsewhere on the farm - yes plastic, but better than loosing nuts at inconvenient times or where the mower will eat them.

Good point Jay, I bet the nylock will take more force to turn than the carriage bolt's square thingie can resist...

I suspect proper jam nuts will cost much more than standard nuts...

Jay, I really wish you'd stop disrupting my perfect plans with your cynical "facts" and astute observations. You shouldn't encourage Mike like that or he'll start in with the "neener neener" stuff. ( Thanks both for your help BTW.) I found a nyloc nut that fit my sample carriage bolt, took off the regular nut, and drove the nyloc on to the torque setting I was using previously. The square shoulder of the bolt stripped out the wood around the edge of the sample hole. The nyloc was in the right spot, but I couldn't adjust it any further until I locked the bolt head in a vise-grip.

Perhaps a lighter torque and/or the bolt going into a fresh hole would do differently, but this is another situation where I'm not going that far out of my way to make an expensive plastic thing work. Good excuse to look back at an all metal solution- Jam nuts sound worth exploring. I see they make something called a "Drake Lock Nut" that is 2 pieces engineered into a prefab jam thingee. Ohhh, and they are only $23 per nut...

Think I'll just buy a second set of thin nuts and put them on over the regular ones. Less than $5 for 100 of them. I think one is supposed to back up the first nut to tighten it against the second, but hopefully this application isn't that demanding.

Yup, two nuts would be cheapest.  Tighten the first until you like how it grips the lath.  Then hold it in place while tightening the second one against it.  Attempt to keep the first nut and the bolt from spinning relative to each other so their relationship stays the same as the jam nut locks them together.

Coydon Wallham wrote:Jay, I really wish you'd stop disrupting my perfect plans with your cynical "facts" and astute observations. You shouldn't encourage Mike like that or he'll start in with the "neener neener" stuff. ( Thanks both for your help BTW.)

We've owned this property for almost 30 years and if there's a way for it to fight back, it does. I married an electrical engineer who taught himself car repair among other things, and #2 Son grew up to be a Mechanical Engineer. Sorry to provide you with "cynical facts", but the short answer is - been there, done that... I'm just trying to save the rest of the (permies) world now.

The "jam" nuts I use on the perches are just a skinnier than average regular nut. They can be skinnier because they're not "load bearing" - the inside regular size nut takes all the load. Theoretically, they shouldn't be any more expensive because there's less material than a regular nut so less metal to make them and less weight to ship them and less volume to take up in the truck. However, "should" and "are" don't always equate.

As Mike says, two regular nuts will do the job just fine, if that's the cheapest option. Hubby still thinks you should go for stainless, but he's a perfectionist! Stainless has its own weaknesses - more brittle for example, and much greater tendency to gall.

Often there are no "perfect" solutions particularly when the word "affordable" gets involved. Hopefully you're learning a lot as this project inches its way along to completion! Hopefully you learned a bunch of new skills at the Lab for the winter?

Greatly considering a yurt when I get to the bush... Not the heaviest of materials required. Should be quite suitable for Zone 6a/b.

I realize I'm late, but wanted to share a few thoughts re DYI yurts. My ex built and lived in one through several winters. He had pallets on the floor and carpeting. Any of the plant materials mentioned by people would make abundant habitat for critters. He strung a cable through the tops of the lattice wall pieces and rested notched rafters on it. He cut up a 2nd hand Army tent for the roof and walls. The roof pieces were layered on and tied down, which eliminated the need to sew fabric into a circle. Don't remember how he attached the wall, but he didn't do any sewing. He had a med sized Pentagon stove in it which held a fire for at least 8 hours. He insulated the walls with moving blankets. People who lived in drafty old houses said his place was warmer than theirs.