PTJ Event 2022 - Solar Yurt Design

Arrived early to get a head start on site prep for this project!

I've been doing lots of digging, as the proposed site is on a hill and there is about a 4 foot+ height differential form East to West. So I've carved out and built up the site to more or less level.

Next I think I'll do some more carving out on the south side to level it for a flat sort of front porch area, and in case later they build a 'greenhouse' add on.

There's another week before the PTJ, let me know any ideas you have about landscaping around the site.

P.S. Eventually there will be a swale built uphill to direct surface water away from the site.

~ Michael O.

Is there any chance the ger will arrive before the end of the ptj?

Update!  Our Mongolian Yurt did arrive!   Ready to be put up in spring!  

Here are some pics of it assembled before shipment!
Here is just the frame:


The front door:


Inside looking out!

Interesting design concept attaching short, rigid wall sections to the door. What will cover the window openings?

Looks like maybe we can get this thing set up this year . . .

Just got this food-for-thought from Michael.

Michael Ot wrote:I assume I would be doing the project I wasn't able to complete last year. The yurt with earth coupled floor.

The yurt is there and waiting I believe. It can go up right away, and the earth works can be done inside. Something that was discussed is the yurt is not capable of holding large snow loads. So the WL staff has to be prepared to brush snow off in the winter, or we have to build a heftier frame to go up with the yurt.

Simplest execution:
- Raise and level the yurt on the pad.
- Clear any growing stuff and build a stone stem wall around the interior of the yurt.
- lay down drain rock and install the earth floor inside the stem wall

Extras that would improve the performance of the build:
- Accompanying 2x6 framing to prevent collapse from snow build up (could also make the yurt taller depending on how it's done)
- Insulation underneath floor (pumice, foam glass or other natural rigid insulation)

Here is a great video showcasing the type of earth floor I planned to install: https://www.youtube.com/watch?v=TSIsEF3nybA

There's a lot of potential to add to this project in the future as well. Cob walls could be built on the stem wall for additional thermal mass. A rocket heater could be installed. A glazed addition could be built on the south side to create a "greenhouse" effect to assist passive performance. Geothermal cooling tubes could be installed for passive cooling in the summer...

Here is a materials list for this project.

Materials List for Yurt Earthen Floor:

- About 70 linear feet of stone for drystack stone stem wall. Wall should be about 8"-10" tall and thick. Large flatish stones are ideal. Alternatives to stone include brick, urbanite, or cinderblock.

- About 150 cubic feet or 1.5 ton of drain rock, such as 1" washed stone gravel or similar.

- About 250 cubic feet or 2.5 tons of compactable fill dirt. Should be roughly 15-25% clay to 85-75% sand. One of the sub-soil samples taken last year from somewhere on the lab was found to be suitable, I don't know where but I believe it was labeled and kept. Or just buy road base, compactable fill or engineered fill from an aggregate supplier (Check to make sure their fines are clay, they shouldn't mind if you ask to take a jar sample).

- A few buckts of sand to add to the final layers to reduce the clay content of the mix down to about 10%.

- 3 gallons of Boiled Linseed Oil and 3 gallons of Turpentine paint thinner. BLO can be bought in paint stores or departments and is commonly used for sealing wood, we can use it to seal the floor. Turpentine thins the oil and helps it penetrate deeper and dry faster without having to apply it hot.

- (Optional) Fibers for tensile strength. Chopped straw most likely but wool would also work. You can get a bag of straw chicken bedding from a tractor supply store that works great and is quite handsome in the finish.

- (Optional) Recommended 100 cubic feet of rigid insulation. Pumice gravel is the most likely option. A more unique material is foam glass which would be quite interesting to experiment with and be a very good subfloor insulation, but could be harder to come by.

- (Optional) 500sqft of 6mil plastic is recommended as a moisture barrier underneath the floor. But I know how y'all are about your plastic. We can go without it, but the floor will be more vulnerable to water damage from underneath. In this case the more precautions for avoiding flooding under the yurt the better.

Tools and Equipment for earth floor:

- A hand tamper, for leveling and compacting the gravel and fill dirt.
- 4 to 8 feet of metal lathe/mesh for sifting dirt. Sturdy 1/4" mesh, and a 1/8" or finer mesh. Plus some screws and wood to put together a sifter.
- 1x1 lumber sticks for screed bars, an 8ft piece or two is probably enough.
- Wheelbarrows and/or mixing tubs.
- Clean paint rollers, brushes or rags for applying seal.
- I have trowels, but we could have more if more people want to work on the floor.
- Shovels, buckets... you know the things.

Materials for Optional Yurt Frame Reinforcement:

- 16 2"x6"x10' boards. These are the beams that hold the roof up.
- 16 2"x6"x8' boards. These are the posts which hold the beams on the outside.
- 120 feet or so of 2x4 to brace between the post and beams and keep it all straight.
- A box of 3" screws, maybe some 4.5" screws.
- (Optional) stain/seal for framing.

I have all necessary tools for the framing construction.

That's lovely, Michael!  Have you been talking with Jeff about plans for finishing?  Maybe we can rope him into this thread again.

I have not communicated with Jeff. If someone can gather materials -- especially the stone, gravel and dirt -- then the floor can be done week 1 probably and sealed by the end of the event.

If week one is shoveling and sifting I'll probably have to just leave instructions for the sealing.

awesome Michael!  

thank you so much!  

I will be up at WL soon.   i will check with Jeff and start looking for materials!

Samantha Lewis wrote:I will be up at WL soon.   i will check with Jeff and start looking for materials!

Samantha, if you and Jeff can come up with a refined materials list of things the Boots can help fetch, that would be excellent. Thanks!

Michael Ot wrote:Here is a materials list for this project.

Materials List for Yurt Earthen Floor:

- 3 gallons of Boiled Linseed Oil and 3 gallons of Turpentine paint thinner. BLO can be bought in paint stores or departments and is commonly used for sealing wood, we can use it to seal the floor. Turpentine thins the oil and helps it penetrate deeper and dry faster without having to apply it hot.

- (Optional) Fibers for tensile strength. Chopped straw most likely but wool would also work. You can get a bag of straw chicken bedding from a tractor supply store that works great and is quite handsome in the finish.

- (Optional) Recommended 100 cubic feet of rigid insulation. Pumice gravel is the most likely option. A more unique material is foam glass which would be quite interesting to experiment with and be a very good subfloor insulation, but could be harder to come by.

- (Optional) 500sqft of 6mil plastic is recommended as a moisture barrier underneath the floor. But I know how y'all are about your plastic. We can go without it, but the floor will be more vulnerable to water damage from underneath. In this case the more precautions for avoiding flooding under the yurt the better.

The items above are the only things we may have issue with.

Regarding the boiled linseed oil: what would we have to do in order to use raw linseed oil for this process?

Regarding the fibers: organic straw isn't easy to find around here. We know a lady who keeps sheep... Maybe she has some wool available for the project?

Regarding the rigid insulation: we've not been able to find pumice gravel in Missoula. We will check with Mud about the possibility of foam glass.

Regarding the plastic: as this is at Basecamp, the rule about plastics isn't as strictly-enforced. This may be a possibility.

Regarding the frame reinforcement: as this structure will be up through the winter, it's likely we'll go with this option. So let's plan to go forward on that as well. Are you looking for maybe 16 2x4s? Would they be 8' long?

Stephen B. Thomas wrote:Regarding the boiled linseed oil: [/b]what would we have to do in order to use raw linseed oil for this process?

Well, you can heat the oil up, ideally to boiling temps, before applying. That also helps it penetrate and dry faster. Working with hot oil is just unfriendly, and whatever pot you boil it in is ruined for anything else. In that case definitely go with a paint roller for application. You could also try to find DBLO Double Boiled Linseed oil which isn't as viscous and can go on at room temp without as much fuss, though I might still warm it up for expediency. Also make sure to get another gallon or two.

Stephen B. Thomas wrote:Regarding the fibers: organic straw isn't easy to find around here. We know a lady who keeps sheep... Maybe she has some wool available for the project?

Chopped wool would work. Horse or cow manure is a good source of chopped fibers, as well as organic polymers that are also good for structural earth. We don't need very much a wheelbarrow full is probably good. We also don't strictly need it with this type of floor in my opinion, as long as we have enough sand in our mix. It's just something for extra tensile strength.

Stephen B. Thomas wrote:Regarding the frame reinforcement: as this structure will be up through the winter, it's likely we'll go with this option. So let's plan to go forward on that as well. Are you looking for maybe 16 2x4s? Would they be 8' long?

I recommend 2x6 for that span. If we used 2x4 I would want posts in the middle of the beams, which would severely reduce the utility of the yurt. This is the list I came up with.

- 16 2"x6"x10' boards. These are the beams.
- 16 2"x6"x8' boards. These are the posts.
- 120 feet or so of 2x4 to cross brace between the posts and beams and keep it all straight and strong. Perhaps additional posts for under the central post.
- A box of 3" screws, maybe some 4.5" screws.
- (Optional) stain/seal.

I have an idea of how it goes together, basically there will be 16 2x6 posts around the exterior in between the poles. Maybe these could be 2x4, but I'd feel better about 2x6. Sitting on those posts and the provided central post will be 16 2x6 beams. This will elevate the roof by the height of the 2x6, but it's the least invasive way I can think of to build it, meaning without cutting or screwing into the original yurt structure.

Now that I think of it, rope or cord to lash the beams to the central ring and some leather or cloth pads to protect it could be a good idea. It would be a shame to alter or damage the original yurt.

OH something I forgot to list; if you don't have an issue with Borax, it would be good to mix a few cups of that into the floor to discourage ants and other bugs from digging. Borax is a simple natural mineral but it is toxic when ingested. We could add it to the sub floor and not the finish coats. There's also diatomaceous earth.

You know what I forgot, 32 3"x6" mending plates for connecting the beams to the posts would be smart.

Michael Ot wrote:
This is the list I came up with.
[...]
- 120 feet or so of 2x4 to cross brace between the posts and beams and keep it all straight and strong. Perhaps additional posts for under the central post.

Yep, we saw your list. When I mentioned 2x4s I was talking about this item. What lengths would you need the 2x4s to be for the cross-braces? I would like to know so we can mill and/or purchase some, and then cut as necessary at the lengths you need.

I have an idea of how it goes together, basically there will be 16 2x6 posts around the exterior in between the poles. Maybe these could be 2x4, but I'd feel better about 2x6. Sitting on those posts and the provided central post will be 16 2x6 beams. This will elevate the roof by the height of the 2x6, but it's the least invasive way I can think of to build it, meaning without cutting or screwing into the original yurt structure.

Now that I think of it, rope or cord to lash the beams to the central ring and some leather or cloth pads to protect it could be a good idea. It would be a shame to alter or damage the original yurt.

OH something I forgot to list; if you don't have an issue with Borax, it would be good to mix a few cups of that into the floor to discourage ants and other bugs from digging. Borax is a simple natural mineral but it is toxic when ingested. We could add it to the sub floor and not the finish coats. There's also diatomaceous earth.

I will pass the above info along to Paul and Jeff. Regarding Borax vs. DE, I think DE is what we would go with though I will confirm so everyone's on the same page. I agree that man-handling the original structure would be a total bummer.

Thanks again for your patience, Michael!

Ah, I understand. The cross bracing will be cut into short pieces that go in between the 2x6 laterally. So it doesn't really matter. 8' pieces are fine, whatever is most cost effective.

Don't worry about cutting the 2x4 cross bracing to length. Making cuts on site will be simpler and more accurate.

Michael Ot wrote:

Stephen B. Thomas wrote:Regarding the boiled linseed oil: [/b]what would we have to do in order to use raw linseed oil for this process?

Well, you can heat the oil up, ideally to boiling temps, before applying. That also helps it penetrate and dry faster. Working with hot oil is just unfriendly, and whatever pot you boil it in is ruined for anything else. In that case definitely go with a paint roller for application. You could also try to find DBLO Double Boiled Linseed oil which isn't as viscous and can go on at room temp without as much fuss, though I might still warm it up for expediency. Also make sure to get another gallon or two.

I think Boiled Linseed Oil is not used at Wheaton Labs because of the metallic drying agents in it, which would give off VOCs. Reading up on it, it looks like Stand Oil is boiled without the added agents, but is stable and more viscous at room temperature? I'm reading DBLO is also viscous and non-toxic. It sounds like Stand Oil that is boiled a second time without adding the metallic junk. Is this to make it more viscous and/or dry faster? The article I found didn't make a direct comparison between the two.

How about simply adding Citrus Solvent to Raw Linseed Oil? Citrus Solvent is food grade and non-toxic throughout the production and use stages. RealMilkPaint has been selling it for what seems like an affordable price.

I use Pure Tung Oil mixed with Citrus Solvent for my wood treatment. Out of personal curiosity, any idea how Tung Oil would work on earthen floors?

Stephen B. Thomas wrote:Regarding the frame reinforcement: as this structure will be up through the winter, it's likely we'll go with this option. So let's plan to go forward on that as well. Are you looking for maybe 16 2x4s? Would they be 8' long?

For the last two months I've been using a yurt that I left up in Wisconsin while I spent the winter at Bootcamp. The dimensional lumber I used for it is undersized and sparse compared to what I've seen of this yurt. The tops of the walls broke at some point, I suspect as much because the knots holding the lath together had grown slack and the wall was not supported straight, as because of the snow load. But the bulk of the wall and the ring with it's 40 spindly little rafter poles has remained supported through all of the snow and winds from January through April without any attention.

The Basecamp yurt has more lath and rafters in the construction than my yurt, as well as two large beams supporting the ring directly. I'll bet the lumber is thicker and of higher quality also. There was more snow here in Wisconsin after I got back in April than I experienced in Missoula the entire three months previous. I don't think that yurt would be in danger of collapse there, though I would encourage cleaning any snow off the roof periodically to avoid developing the kind of sag the tepee poles have shown over the seasons...

Coydon Wallham wrote:I think Boiled Linseed Oil is not used at Wheaton Labs because of the metallic drying agents in it, which would give off VOCs. Reading up on it, it looks like Stand Oil is boiled without the added agents, but is stable and more viscous at room temperature? I'm reading DBLO is also viscous and non-toxic. It sounds like Stand Oil that is boiled a second time without adding the metallic junk. Is this to make it more viscous and/or dry faster? The article I found didn't make a direct comparison between the two.

How about simply adding Citrus Solvent to Raw Linseed Oil? Citrus Solvent is food grade and non-toxic throughout the production and use stages. RealMilkPaint has been selling it for what seems like an affordable price.

I use Pure Tung Oil mixed with Citrus Solvent for my wood treatment. Out of personal curiosity, any idea how Tung Oil would work on earthen floors?

Yes I suppose you would have to source raw linseed or something else to not get the drying agents. But you might be applying coats long after I'm gone, waiting a week or more between coats for raw oil to dry. About any kind of oil that hardens as it dries will work technically. Linseed oil is the only oil I have worked with and is the most popular option, but there is also walnut oil, peanut oil... tung oil is more for countertops from what I've read gives you an almost lacquered kind of finish.

As for thinner, citrus oil and also odorless mineral spirits are alternatives to turpentine. But even citrus thinner has some dangerous stuff in it right?

Also, we don't HAVE to seal the floor at all. If the decision is complicated, we could instead spend the time making clay powder and hard troweling the floor to a polish, and then wax it with carnauba wax a couple times a year. Or not even that, just make a nice solid raw earth floor. It will break down and dust over time, but that won't kill anyone and you can always seal it at any point in the future.

Michael Ot wrote:Yes I suppose you would have to source raw linseed or something else to not get the drying agents. But you might be applying coats long after I'm gone, waiting a week or more between coats for raw oil to dry. About any kind of oil that hardens as it dries will work technically. Linseed oil is the only oil I have worked with and is the most popular option, but there is also walnut oil, peanut oil... tung oil is more for countertops from what I've read gives you an almost lacquered kind of finish.

As for thinner, citrus oil and also odorless mineral spirits are alternatives to turpentine. But even citrus thinner has some dangerous stuff in it right?

It looks like odorless mineral spirits and turpentine aren't as bad as I had supposed, and anything with the power to thin and clean like that has immediate harmful characteristics, but the citrus solvent claims to be somewhat less toxic in most ways from what I can tell. Here's the sales pitch from Realmilkpaint.

Tung oil is good to use on any wood that could use preservation. I think it is most well known historically as being used to protect the Chinese navy from rot before the industrial revolution reached them. Compared to linseed oil treatment it is better in almost every aspect, but it costs more and is likely not something most homesteaders could produce from scratch.

I regret to inform that I have had a catastrophic vehicle failure in southern Colorado, and am stuck until I can get it fixed. More than likely this will be no sooner than Wednesday, as La Veta Colorado is a one garage town and it's 4th of July weekend. Meaning the earliest I might get to the event would be Friday.

There is a chance I will be able to figure out the issue and fix it myself, but almost certainly I will not be there on Monday to kick off the event and help put the yurt up.

Michael Ot wrote:There is a chance I will be able to figure out the issue and fix it myself, but almost certainly I will not be there on Monday to kick off the event and help put the yurt up.

Would the yurt be erected before the floor is done and sealed?

Looking at the foundation as is, there is some rock sticking up near the back that would prevent an even ring for the perimeter where the yurt wall would sit. Is the floor construction meant to raise everything up so this will not be an issue? Perhaps we could have someone here work with the jackhammer to level it off before you arrive if that would help...

Hope the repairs go smooth, it will be good to see you back.

Coydon Wallham wrote:

Michael Ot wrote:There is a chance I will be able to figure out the issue and fix it myself, but almost certainly I will not be there on Monday to kick off the event and help put the yurt up.

Would the yurt be erected before the floor is done and sealed?

Looking at the foundation as is, there is some rock sticking up near the back that would prevent an even ring for the perimeter where the yurt wall would sit. Is the floor construction meant to raise everything up so this will not be an issue? Perhaps we could have someone here work with the jackhammer to level it off before you arrive if that would help...

Hope the repairs go smooth, it will be good to see you back.

My plan was to put up the yurt first. Otherwise we don't know the exact dimensions of the floor.

Maybe erect the yurt as it's meant to be and leave it for a day. Then remove the coverings and build the reinforcement. Then put the roof covering back on and leave the walls off for air flow and build the stem wall and install the floor.

As for the rocks, the pad is a bit bigger than the tent, so I was hoping that the flexible  yurt wall could just be fitted around the stones and just cause a little uneven bump on the inside.

I poked the stones with the jackhammer a bit last year to see if they wanted to come apart and they were solid, but if someone wishes to try they may.

One of the major bedrock outcropping bumps is about 15" high and 30" across where the wall would have to sit. That is a pretty big obstacle to work around. It looks like if the cut/fill is continued a few feet to the north of the current location so that the structure could be assembled more in that direction, that outcropping would only be about 6" tall and wide where the wall would cross it, the one north of it would end up inside the wall instead of under it, and the bump south of it would be outside.

Jeff B mentioned concerns about assembling the wall on the current grade and building the floor inside as that would mean the loss of headspace for inhabitants. I heard you describe the floor construction to Paul in a podcast, but don't recall the total thickness of it, what would that be? Is there a reason not to build it up all the way out so that the walls would sit on the floor also? I'm estimating that if the center is moved 3-4 feet north and the floor is at least 6" thick all the way out, the stone barriers would end up below grade and the wall could sit just about level all the way around...

Alright so we got the yurt up and some of the floor installed before the event ended.

We were very crunched for time, I arrived 3 days late and we didn't have many hands as by then most folks had committed to other projects.

BUT despite this we were able to erect the yurt frame, construct a simple stem wall and lay the drain rock, moisture barrier, subfloor and more than half of the finish floor.

Well... It would have been the finish floor bit in my haste I allowed us to use a more wet mix than recommended and this has apparently resulted in shrinkage cracks across the surface.

So it will not only need the remainder of the layer layed but also another thin coat over the top maybe a quarter inch to patches the cracks and make a smooth finished floor.

But that will have to wait for another year unless someone wants to tackle it in the meantime.

Here are some pictures of the beautiful ger erected. We had an incident with group confusion over how to put it together where we ended up leaving the wall sections standing unsupported as a freak wind came by. It seemed like damage was negligible at first, but a couple of the more modern additions to the structure came out with some bruising...

Below is a pic of the floor after I think it had fully dried. Michael notes above what he thinks could be done to finish up the main area given some more time to work on it.

My pics show there is an entry way that is seperated from the rest by the stem wall curving in. Michael left this to have an entry way where people could leave wet gear and other things that might damage the earthen floor. Jeff Bosch suggested we add a layer of pea gravel on top of the rocky gravel there to make it more welcoming.

On the Monday after the event I spent the morning working with Liam and Daniel to shore up the support for the outer wall since we ran out of time with Michael during the event. Liam did a good deal of labour to build a skeleton that will hopefully allow the material we added to the NE side so settle into a supportive slope. I tried to spread out some appropriate sized rocks of increasing size from W to E to lift the frame off of the soil and level it off. I ran out of time and had to move on to other boot duties so not too happy with the result.

I didn't have time to check on the level of the overall structure and how it falls in line with the walls being perpendicular. The walls should also be treated with linseed oil but that was another task we didn't have time for. Finally, the whole structure should have all of the various layers of felt and canvas installed before it sees any snow that might be sitting on it. We didn't have time during the events, but it will need to be done before winter. Taking down and re-erecting the whole thing will probably be a time consuming task in itself, but could allow for wood treatment and more balance construction next time if someone with some experience is involved...

I wanted to check in with Michael and Coydon regarding the to-do list for this project. Maybe something like this?

- complete the finish floor
- pea gravel to entryway
- treat wood walls with linseed oil
- install felt and canvas walls

...Anything else to add to the to-do list? Please note it here. Thanks!

Stephen B. Thomas wrote:I wanted to check in with Michael and Coydon regarding the to-do list for this project. Maybe something like this?

- complete the finish floor
- pea gravel to entryway
- treat wood walls with linseed oil
- install felt and canvas walls

...Anything else to add to the to-do list? Please note it here. Thanks!

The finish floor would be a considerable undertaking. What is there now was 4 of us working on it for almost a full day, including Michael who has extensive experience with earth floors. As he notes above, we were rushing just to do that and thus the mixture proving to be too wet and the resulting cracks. You might want to wait for an experienced ringer if you are going to tackle this, if not for Michael to return.

BTW, I think the floor as is should be usable for people in soft shoes or bare feet or laying down (IE yoga).

Pea gravel would be nice and easy to do, but not a priority until the rest of the floor is done.

Treating the side walls (the collapsible lattice work) would be the top priority. The wood around the windows and door, the rafters, the ring, and the support beams all have a light treatment on them, but the collapsible walls are untreated. One coat of pure linseed oil mixed 50/50 with whatever solvent is acceptable would be a great improvement, and a second coat would probably help. I do two coats of tung oil on my pine materials, but not familiar with specifics of linseed oil or what wood was used here.

I would consider putting on the felt and the rest of the canvas to be winter prep. If you need links to instructions and videos on this, myself, Jeff B or Samantha could provide them. From watching the videos, I got the impression this is more difficult than one would think just looking at the materials.

One other to-do would be to weatherize the ceiling ring. I put the small square textile cover up with some makeshift rope and quick knots, so this needs a better solution after the walls go on and the glass is installed. Even with the glass sections in place, there is an open centre ring so the smaller textile cover should be in place by default. The glass inserts that are now sitting by the tarped felt should be caulked and placed up in the ring. When I talked with Jeff B he seemed to have a better grasp of exactly how this would best be done than I did, and his thoughts varied slightly from the 'official' instructions, so check with him.

I recall hearing there were some instructional videos on how to build the yurt. Anyone have links to those they can share here?

I hope this is okay to post here, there are some more details that i will PM to you:
> Setup Video - https://youtu.be/Uxftskhhy8w
> Setup Written directions - https://docs.google.com/document/d/1xQKGlvLcYFWWtjKnq3HJhad5oQib9SYeFfetntArAps/edit
> New website - https://mongolianyurts.org/

These are what were sent by the ger importers. There are gaps and missing details that caused a few headaches setting it up during the PTJ, assuming floppy orange hats aren't impact rated...