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The strongest structural shape is the arch. (To all proponents of the triangle, I’ll see you in the comments.) As a model for compression-focused design, the arch represents one of the oldest forms of construction, dating back to ancient Rome. And because compressive forces are distributed efficiently along its surface, an arch can span wide distances without the aid of other large structural supports like beams and columns. It’s any wonder why the arch, in whatever form, isn’t a favorite of the green building community.
At least one set of people appears eager to shift that thinking. Marie Saldivar, a realtor and licensed contractor, and her husband Kurtis, are co-owners of the startup Steel Hut, which they officially formed last year. Based in Sisters, Ore., a remote rural community abutting Deschutes National Forest (that’s wildfire country), Steel Hut produces prefabricated kits and plans for a small but growing variety of steel-arched homes, also known as Quonset huts. (“Quonset” is an Algonquin word roughly translated to “small, long place,” which isn’t a reference to the structures themselves but the place where they were first produced in 1941, at a naval construction post on Quonset Point, R.I.) In late 2024 the Saldivars completed their first residential prototype, a 1200-sq.-ft. guest house on their 10-acre property in Sisters.
“We see these buildings all over the American landscape, but we almost never acknowledge them as an aesthetic form. People only see function,” says Marie. The utilitarian nature of Quonset huts, which to date have been built almost exclusively for agricultural and industrial uses (and most famously as temporary barracks during World War II), certainly factors into this thinking, according to Marie. People just need to “reimagine what these buildings can be used for,” she says.
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11 Comments
Beautiful and I especially love the windows!
Justin,
This being GBA where we typically deal with the meat and potatoes of building envelopes, I wish there had been a bit more discussion about how the wall / roof assembly works.
I’ve built two quonset huts as workshops over the years, and found some real complications trying to insulate and attach finishes to them - related to their shape and the method by which they are connected.
The profile of the panel ribs mean only foam is a viable option to insulate, and it will vary widely in R-value based on the differing depth of the cavity. Connecting to the shell for everything from internal partitions and finishes to wiring means either penetrating what is both structure and cladding, or adding connectors to the gasketed screws holding the panels together, which can compromise their watertightness.
The arched shape, while stable structurally, also means you end up with what is essentially a flat roof near the top, which is only protected by exposed fasteners and lapped panels - something we don’t rely on in other types of construction.
Related to that, the exposed fasteners on the panels have a limited lifespan, but unlike those on metal roofs can not be replaced without access to the underside. I don't know what you do with a finished interior.
You can make a home in one - people have been doing that for the best part of a century now - but the inherent limitations of the shape and shell mean they will always be a niche construction method.
I suggest the building offers two significant improvements over conventional buildings. 1 is the speed of construction, and 2 is the ability to split the load if access to your build site is difficult. You can obtain an unheated, but weather tight enclosure in a hurry.
arc2arcnailer,
I agree. They are great for workshops and barns, etc. I worked out of one for over 20 years. Much like pole structures, the complications only occur if you want to condition and finish them. I got around that by making a room within the Quonset with space between it and the exterior walls that I heated for storing paints, wet clothes, etc.
Adding to Malcom's astute observations, is there any data to suggest that this would outperform a fire resistant assembly using traditional methods? From everything I've seen, without fire resistant exterior shutters, even full on fire rated laminated windows are the first point of failure in traditional exterior assemblies using noncombustible exteriors and proper WUI detailing. Sierra Pacific doesn't seem to offer any fire rated windows, so these are likely just basic WUI code minimum with one tempered pane and either wood or vinyl frames (h3).
The bigger question we should be asking is whether there are ANY permanent structures, especially homes, that can be built in fire adapted ecosystems sustainably. Unfortunately people love living in forests and deluding themselves that they can take credit for the biogenic carbon storage just because they own the land, while ignoring all the negative externalities. Here in California we're facing an implosion of our home insurance market and paying some of the highest utility rates in the country due to the costs associated with serving communities in fire adapted habitats.
I'm also very curious about wall and roof assemblies, connections to the outer shell and insulation.
Being a metal worker, I wonder about the possibility of tack welding brackets to the inner side of the shell to support interior framing. Perhaps this approach could this facilitate blown in cellulose?
If the exposed fasteners can only be accessed from the inside, I see that as a deal breaker and huge liability. Malcolm, can you picture any hacks around this with some inventive metal work?
D_Hallowell,
There may well be work-arounds for the problems I’ve seen, however my feeling is the building method may simply be a bad match for trying to make high performance housing. Each type of technology - ICFs, pole buildings, SIPs, rammed earth, etc. all have inherent in them certain strengths and limitations. It may be better to use them where they obviously make sense, than to go though a lot of gymnastics to try and adapt them for what are basically unsuitable situations. However, I may be wrong. I’d be interested t0 hear a defense of Quonsets from someone with more experience.
Specific to this particular build, a few things surprise me: There appears to be a completely un-insulated concrete stem-wall around the perimeter extending up into the living spaces, all the walls and ceiling are insulated with a thin layer of cellulose, with no apparent way to dry to the outside, and are framed with steel studs, so they will have a lot of thermal bridging.
Several comments to you post;
If you chose to spot weld a connection I suggest you be mindful of the visible and now uncoated exterior of the corrugated panel at the weld pool location.
If you are a creative type it may be possible to place a spring clip type retainer (think auto body panel retainers) on the panel at the overlap. This would probably require a strip of butyl tape for sealing which has its own ease of installation issues.
I was noticing that stem wall too. Yikes.
I watched a video at the Steelmaster site and it looks like basic through-bolt construction for the quonset structure. The interior nuts could be tack welded so they wouldn't shift on any future bolt removal. But again, a lot of gymnastics.
I do some building on remote islands in Maine where there's no available concrete and extreme labor shortages. If the problems could be thought through and overcome, I like the idea of a structural roof and siding solution that could arrive on a flatbed. Pins as used on pin piers could likely anchor the Steelmaster base connectors. I've had good luck driving piers through the rocky Maine soil. Pic attached of a test pin pier I fabricated attached. They're incredibly secure. I tried to shift or pull this one out with a small tractor and couldn't move it.
I wonder about a raised pin pier foundation with the quonset structure assembled over it, creating a vented crawl space below. A non structural frame could be built on the deck with dense packed insulation in the walls and blown in in the attic. Seems pretty straightforward except possibly detailing the air barrier at the floor to quonset structure. Maybe a taped cnc'd form out of ply? ... Gymnastics again.
Food for thought.
D_Hallowell,
Both the Quonset huts I built came with instructions to embed the panels in concrete footings / stem-walls. I opted instead for a base-flashing they offered that conforms to the panels contours and can be bolted to either the thickened slab or wood frame construction. With the base condition dealt with, I don't see why y0ur plan wouldn't work.
Insulating the walls and roof with cellulose seems tricky as the exterior skin is impermeable, so you get no outward drying unless you can establish a ventilation path - which needs to be open at the bottom and top.
None of the difficulties I listed can't be overcome, and perhaps in circumstances like yours they would make sense. That's a different question from whether the house featured here is a useful prototype for widespread adoption.
Thanks for the input.
Agreed.
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