Straw Bale Roundhouses Built in One Day

Strawbale roundhouses like this can be built in as little as one day.
Strawbale roundhouses like this can be built in as little as one day.

A kindred spirit sent me a memorable letter about 10 years ago. They had read about the strawbale roundhouse I helped build with the Lakota Sioux in South Dakota. (I recently found out the roundhouse later got destroyed in a flood.) For some reason the straw bales on that particular project were very difficult to bend into shape. Normally you can set one end of a bale on a raised object such as a small log, stomp the side of the bale in a few places and end up with a curved bale. Well, these bales would spring right back to their rectangular shape. So we’d stomp them again and again until they ‘cooperated’. But the bales would still gradually straighten out somewhat in the wall. We successfully finished the shell of the house on schedule, but I’ll never forget those bales.

I was pleasantly surprised to hear from the author of the letter that they build strawbale roundhouses in one day. I never got around to mailing them back for some reason and I’ve always wanted to connect with them somehow. Maybe they’ll see this blog post and write again.

Turnbuckles are used to tighten steel cable around the roundhouse.
Turnbuckles are used to tighten steel cable around the roundhouse.

With that background, here’s the basic process they use. It’s quick and easy to stack bales. They’re like pre-made giant building blocks that can be set in place by one person (or two people who are less strong). The tedious part as mentioned above is keeping the bales in alignment (= perfect circle). The author uses ¼” steel cable and turnbuckles on each course of bales. The cable is wrapped around the roundhouse and the ends fastened to each side of the pre-set door buck. The turnbuckle is added in a convenient location and then tightened until the bales are cinched into the desired radius. The turnbuckles are embedded in thick exterior plaster.

Image source: (Random image of strawbale roundhouse for illustrative purposes) Design
Image source: Techni-cable

14 thoughts on “Straw Bale Roundhouses Built in One Day”

  1. Owen is correct. Tension cables should be routed to avoid door and window openings. This applies to the vast majority of designs that are typically covered on this blog.

    However, in complex designs, (more complex than a simple roundhouse), it may become strucurally necessary to have a tension cable that passes through a door or window opening. In those situations, (rare for simple structures) the tension cable would need to be attached to an extremely strong door or window buck, pass around the structure, and then attach to the other side of the extremely strong door or window buck. The buck itself essentially needs to be strong enough to withstand the tension loading exerted by the cable. It is as if the buck becomes an integral part of the tension cable.

    These situations are fairly rare, at least when it comes to small houses, and are best designed by an engineer to make certain all the components are properly sized and designed to withstand the loads to be placed upon them. If someone finds themselves confronted with such a complex design problem, it would be wise to consult with an engineer.

    A few of the types of designs to watch out for that may require specialized engineering assistance might be multiple interconnected round rooms that are on split levels especially if they are self supporting walls and not post and beam supported, or special shear walls such as is often needed in seismic areas. If someone finds themselves wanting to build any more complex design, engineering help to get the details correct is money very well spent.

    Of course, anyone who is unsure of any design, no matter how simple would be wise to get expert advice from an engineer if they feel it is needed.

    At the same time, it’s your house. If you’re building in an area with few or no building codes and are willing to experiment and take some risks… Build it your way and see what happens. Just use common sense and stay safe. If it falls down or otherwise fails, just rebuild it. Just remember that the added expense of rebuilding was the risk you chose to take by not seeking expert advice. Smile and take it in stride.

    Freedom to build it the way you want gives you the freedom make your own mistakes as well as make your own successes. One rarely achieves one without at least some of the other.

  2. In the situation of using any tensioned wire to wrap the roundhouse, how do we deal with the doors and windows where the wire would need to be re-routed or tied in somehow? What is the best technique anyone has found?

    • This method is primarily for small, simple structures with minimal doors and windows. The tensioning wire would begin and end at the door buck (ex: screw eyes). It would go above and below windows. At mid-window height there might be one wire that’s between window bucks.

  3. In hygroscopoic walls is there any risk that metal components like cables, wires, turnbuckles, etc, could deteriorate over time and eventually fail?

    About tensioning opotions, I’m currently plastering a wall that ended up with some barbs from the barbed wire on the outside due to a design misjudgement. Never, ever again will I do this. It makes plastering very difficult. Anything but barbed wire, I say.

    • Steel components are always susceptible to rust. That’s why I always recommend a good roof and large roof overhangs.

      Barbed wire: Did you use earthbags? I don’t see how the barbed wire could end up protruding into the plaster.

      • I laid the barbed wire in the normal way, but left it longer than necessary and then wrapped it up and around the end bag of the next layer to better secure half bags that were laid to ensure a running bond. Bad idea. It’s a low wall that I built to support a bamboo hut that I bought for my garden. 4 courses above grade.

        • That’s good to know. This is an idea we show on our blog for earthquake areas but haven’t tried yet. Thanks for sharing.

  4. They sent me a photo. The roundhouse in the photo was quite small — about 12′ interior diameter.

    Reflecting on this now, this building method seems like the fastest, easiest way to obtain durable, substantial shelter. Sure beats living in a tent. You could move in right away and finish it over time. It would be warm and comfortable enough in winter in northern climates, assuming you insulate the roof with R-45 or so and add a wood stove. Some people put bales on the roof and cover them with a tarp. I would use wood poles from a forest for the reciprocal roof.

    So this explains my love affair with straw bale construction, and why building methods such as cob seem way down the list. You can build the shell of a small building in one day instead of spending months.

  5. I suspect that using barbed wire and a simple barbed wire fence stretching tool would be much less expensive than 1/4″ steel cable, even if you needed to use multiple loops of barbed wire on each course.

    If a barbed wire fence can be stretched tightly enough to withstand a butt scratching from a 2000lb cow, I suspect it would be sufficient to hold straw bales in place nicely.

    If someone doesn’t want to hassle with the barbs on barbed wire, you could probably get away with typical electric fence wire. Again, it should be dramatically cheaper than wire cable.

    • Wire is added after each course of bales to make sure every course is the right size. Barbed wire on the outside of the bales would be a safety risk. Some might consider it an acceptable risk. Personally, I’d look for something safer. Not sure if electric fencing wire could withstand the tension. Seems like it would work. That sounds like the best option so far. Thanks for sharing.

      • You can buy barbless wire or high tension wire, either can be stretched and tied or crimped at a fraction of the cost of cable + turnbuckle. High-tensile wire is stronger than 1/4 inch cable and is $100 for 4000 feet (yes, four THOUSAND feet in a roll). It also make wonderful grape or vegetable trellis. Barbless wire is more expensive, but easier to work with, especially without special tools.

        You can buy fence tensioners (strainers) that will pull each band tight for a few bucks each.
        Or buy the traditional stretching tool once for $40.

        The cost difference is significant on even a small project unless you scrounge a very good deal on cable and turnbuckles.


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