Michael Ot

Last year I attempted to erect the yurt and install an earthen floor. However, I had vehicle problems leaving Colorado where I had been on a hempcrete install, and arrived 3 days late.

Despite this and other complications, we managed to erect the yurt and install a containing stem wall and the subfloor. We weren't able to do any finish floor until the very last day, there wasn't time for proper soil engineering and test lays. The rush job ended up being too clayful and wet and cracked all to pieces, even de-laminating itself from the subfloor. This year, now that the preliminary work is already complete, it is a great opportunity to take our time and do proper structural earth engineering for earth building, specifically earth floor.

Assuming that the yurt area is in the same state I left it in last year, then the sequence of events will be more or less:

1. Collect Materials
  -   Earth: I still believe that the "Lemon Tree" dig site is the best place to source earth from. One load in the dump trailer will be plenty, it doesn't need to be very full either.
  -   Sand: The hillside by Arrakis has very sandy loam that will be a suitable less expansive sandy loam to add to the expansive clay loam from Lemon Tree.
  -   Fiber: Straw will add more non-expansive additive to the mix and tensile strength. A couple bags of chicken bedding would do, which is already finely chopped. That or unchopped straw can be chopped with the assistance of a leaf mulcher. Or fine fiber can be added with horse manure, which also comes with organic polymers that strengthen the material.
  -   a small amount of diatomaceous earth would also be a good additive to discourage burrowing insects from digging through the floor.

2. Engineer and test mixes.
  -   Once we have enough material we will test several mixes in small areas to determine a mix that will be strong and not crack.

3. Lay Floor.
  -   With the assistance of screed sticks, we'll lay the floor mix down in one or two layers and compress it with rigid trowels.
  -   Once the floor has been laid down and firmed up a bit it will either get a new thinner, more clayful, less fibrous mix layed over top as a finish coat or be wetted and burnished until it has a smooth surface.

We could also begin the process of oil sealing the floor. But it isn't strictly necessary. We could simply do maintenance on the floor each year at the jamboree, touching it up and possibly adding a new skim coat.

Some necessary equipment will be sifting supplies, so lumber for building a frame and quarter inch mesh or so for sifting the earth through. There may already by meshes available to use or re-purpose. Some kind of leaf mulcher would also be useful if we intend to chop our own straw. I will bring at least a couple wood floats for compressing the floor.

If anyone is at Wheaton Labs and sees anything important about the yurt's state I'm not aware of please let me know. Also if it's possible for any of the material to be prepared ahead of time, that would be extremely helpful. Especially just a big pile of dirt.

~Michael O.

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.

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.

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.

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.

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

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.

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

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.

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.