Quonset Questions & Answers from/for Pete

topic posted Tue, March 14, 2006 - 9:41 AM by  Will
Dear Will and Michelle,
NICE JOB!!!!! I have been toying with building a Quonset home for 4 years. Recently, after adding up what I pay in rent, I have been finalizing plans. My plans are far smaller and more modest than yours. Your curved and artistic framing is above and beyond anything I will ever attempt. You two should be really proud!!!!

I am faced with many questions. If you would be willing to answer any of these I would greatly appreciate it. But you probably have a lot of homeowner responsibilities that are more important than my gazillion questions…so take your time.

1- What product did you use for spray on insulation? What R value did you get? How hard was it to apply?
2- How did you ventilate the roof and insulation? Or did you? What is required? Most info related to this is written for people who do not insulate and finish the arcs.
3- Why did you use the base plate foundation instead of the old concrete trough? Any pros or cons?
4- Most steel companies offer an end wall attachment that I believe amounts to a curved angle iron. Is this how you attached the end walls? can I get a photo? How did you seal this seam?
5- Any suggestions for the framing of the endwalls? 2 or 1 section? How did you raise them into the arc? I am very intimidated by this although I have done some framing of traditional buildings in the past. That curve looks hard.
6- It looks like you joined the wall at the lower 7.5” gutter part of the arc, could one do this in the upper seam part of the arc?
7- Most of my literature suggests building the arcs on the ground and hoisting um up. Why did you build it from the sides to the middle as demonstrated in your photo?
8- I noticed your “wood strapping” photos. Is “strapping” the term for this? How far are they spaced? What type and size lumber did you use? Do I see wire loops around the strapping, what are those for? What did you use to fasten this and seal the fasteners from rain?
9- are you planning on putting up drywall or paneling or some other interior finishing? If so what? Are you planning an adding any additional framing to the “wood strapping” for support of the drywall(if that’s what you are using)? How are you calculating how much weight the arcs can hold (weight being insulation, fans, strapping, finishing etc)
10- Do you plan on painting the roof? Why and with what?
11- I have lived in A-frames. The heat went upstairs witch was only helpful when people slept in the loft. I know yours is a proper 2 story but you have an open ceiling. Any problems with heat? Any fans that you are adding and why? Can you give me any suggestions about airflow and heat management in an arc home?
12- what is the “amazing place in Spokane Washington”?

I learned a GREAT deal from your photos Thank you. If not an inconvenience. And if you have them. I would enjoy any closeup photos of your endwall framing, junctures of interior framing to the arc, joining of endwalls to the arc (especially the walls that move perpendicular to the ribs), photos of the strapping and plaster/drywall/finishing if you do so. Any photos of tricky things, things you are proud of, things you wish you would have known about before you started?

Do you have any suggestions for those taking on a similar project? Mine will likely be several long 30x15' arcs.

Nice Job!!!
Thanks for the Photos they taught me a great deal,
1- insulation?

We used Urethane Spray Foam insulation. It is sensational, and honestly, from our research, the only thing that really works for a Quonset, as you need something that will adhere to the metal ? to prevent any opportunity for condensation. We live in an area of serious temperature extremes so we had to put a considerable amount of $ there. We saw it as somewhat offsetting the inexpensive price of the metal building. We paid for 2? ? I think it was $3.50 per foot, but the guy gave us almost double that in many places, and sprayed our wood-framed endwalls for free. We had to have someone apply this stuff, as it must be strayed in through a special hose at over 100 degrees. It?s a very sophisticated system. The insulation adds incredible strength and has no off-gassing to be concerned with.

2- ventilation?
We didn?t have to be concerned with ventilation as there is no area inside the ceiling for air to condense.

3- base plate
We considered doing radiant heat and then decided against it and concrete floor. We?d both lived in lofts in the city with concrete floors ? not the best for your back, etc.

4- angle iron seam?
I think there is a picture of the brackets we used. I had them fabricated of light gauge steel and just attached one to the final arch every 10 feet or so. The brackets have a bolt pattern to match the holes in the arch (bolt pattern), and many holes to facilitate attaching to the wood-framed walls we built. We have about a one foot overhang so sealing is no big deal. We may add an additional arch (2? wide) in the future as we live in a high rain area some of the year.

5- Any suggestions for the framing of the endwalls? That curve looks hard.
The arch is completely self supporting, so you can?t really fuck up too badly with the framing. We started from the main floor, built our first floor framing (with 10? high ceilings), then added the loft level floor joists, etc., then continued up to the metal. We created a simple plywood template to make cutting the sheathing easier. It really has helped with the drywall work as well. As far as the actual framing meeting the curve of the Quonset, we just built these strange looking bits with vertical studs, connected by other 2X6?s which create triangular bits. You can pretty much piece them together bit by bit, as ? once again, they are NOT supporting, just something to attach your sheathing and drywall to. We had Very little building experience before we begun this project. Just some renovation work in the past. It?s a bit of head scratching at times, but not rocket science. Lots of sweat, tools and materials. We just built sections of wall on the floor, (or the loft floor) and then stood them up and attached them. Simple and easy. The little triangular (to meet the curve) we just mickey moused to fit ? as they are not structural.

6- upper seam part of the arc?
The reason we did this, was to take advantage of the flat portion of the profile. We used 2X6 construction. When you consider that the interior of your building will probably be a smooth ceiling, attached to the flat areas of this profile ? thus, that seemed to be the most logical way to attach the wood framing.

7- and hoisting um up?
This was the biggest struggle/frustration we faced. After all this info from the manufacturer telling us how easy it would be to assemble, we had 9 experienced builders here, pulleys, scaffolding, ladders, ropes, winches, etc. and COULD NOT get an assembled arch up. We had the strength and ?mechanical advantage?, but the thing kept flexing like a dragon ? it was really a trip. Our most depressing day. We didn?t know what we were going to do to get our building up. Even using a crane, because of the weight of the arch, you?d have to build a big-ass form in the shape of the arch to support it so it wouldn?t buckle when you began to raise it. We considered so many approaches and then a brainiac relative came up with this plan, where we hinged up each end of the arch, and then dropped in the top sections (there?s an overlap pattern you have to follow for drainage). We ended up putting up the whole building ourselves, just my sweetie and me, achieving about an arch a day.

8- wood strapping/rain
We bought rough 2X4 (actually 2? x 4?) and yes, we wired to the bolt/nut section inside. We attached the strapping (yes, I think that?s correct ? sometimes called furring strips ? but they are usually thinner) every 4? so we?d have enough to attach and curve an interior surface. The bolts all (4500 of them) have a rubber gasket attached.

9- are you planning on putting up drywall
We have begun attaching our interior in some areas. We are using 1/4? hardboard for starters. Then we?ll finish that with a variety of other things in order to give us different finishes. Lots of ideas, no really definite decisions yet. We have done the upstairs bathroom ceiling in hardboard, and may cover that with some sort of bamboo blind, to give more of a tree house look. We ended up with a VERY heavy gauge building ? 14 gauge, the biggest they make, in order to meet the local snow load requirements. This building is VERY strong. The insulation adds much greater strength, when applied, so we have no concerns about load-requirements on the inside. Just the nature of an arch is about the strongest architectural form. I?ll get around to adding some more pictures soon, detailing some of the progress re: interior work.

10- Do you plan on painting the roof?
No, we?ll just keep it metal. We thought about growing hops or something to make it blend in. Who knows.

11- Can you give me any suggestions about airflow and heat management in an arc home?
We have a 22? ceiling and our loft area is virtually open to below everywhere. We installed a large ceiling fan, and are very satisfied with our heating/circulation. It?s gets pretty hot here in the summer, and cold in the winter, so when we get curtains and blinds, it will be more constant. We have a stupid amount of windows (250 square feet just in our living room!) so that is where we have to deal with temperature issues. The building itself, with the insulation is amazingly well insulated. We put it 3 electric baseboards, but primarily heat with wood ? a high efficiency, zero clearance insert by RSF.

12- what is the ?amazing place in Spokane Washington??
Torminos Sash & Glass. 509 534 0537 Window & door wholesaler (John/Lisa)
This place rocks. They don?t have a website, I don?t even think they have an answering machine. They don?t use computers, but they?re a family owned business, around since 1952 and they have amazing deals on windows and doors of ALL Types. All new, but seriously discounted ? discontinued sizes, bulk purchasing, stuff that was ordered by a contractor and then became unwanted when someone changed their minds. They have 33 buildings full of stuff ? incredible.

Anyway Pete,

Thanks for your interest ? great questions which show how serious you are about this.

There are a few things we?ve learned which you should definitely know before you begin.
I also spent a great deal of time on the computer working out our floorplan, blueprint and other details.

Good luck in your project plans.

Will & Michelle,
Gray Creek, Canada
posted by:
  • Even more Questions from Pete

    Sat, March 18, 2006 - 8:44 PM
    Thanks so much for your insight. You confirmed many ideas and changed my mind on many as well. Your answers spawned many new questions.

    -----Insulation/Venting --------------------------------
    Your spray on insulation addressed my frustration with ventilation. Unfortunately (as you said) it is pricey. My plan was to use this type of attachment:
    But I was hoping to use the foil and fiberglass laminate blankets. Then put in little vents on the endwalls. But if the thing is 40 or 50 feet long, little vents won’t cut it. And if I join to another hut as I plan to in the future, no ventilation is possible unless I put vents into the arcs and that decreases strength.

    Is there an advantage to spraying it on as you did versus putting up drywall (for example) and injecting behind it? Besides the obvious time advantage, you can put up your interior finish at your leisure now…

    Since the foam is SOLID do you foresee any repairs, bolt tightening, rewiring, additions, or maintenance that might be difficult?

    Also, I have had a lot of organic chemistry and toxicology classes and I fear what endocrine disruptors might be wafting through my house in 20 years. I really wish the US government would fund and empower the EPA to research products more than the token assessments done nowadays. But I guess if they did that big corporation couldn’t make lots of money by exploiting consumers then could they?...sorry i’ll stay on track now …

    My plan was to find a window company and buy crazy rejected sizes and build the frames around whatever shapes they may be. I know of some in Northern Wisconsin where I am from…But none here in Colorado. If anyone knows of one PLEASE let me know.

    -----Insulating Windows---------------------------------------------------
    I haven’t done any Cost Benefit Analysis yet but I am toying with buying single pane (cheap) windows on the southern exposure endwall and putting in 2 endwalls. Then I could do the “envelope house” thing: Open the exterior wall windows to let out heat in the summer. Open the interior windows in the winter daylight hours to let in the trapped warm air. Shut both at night. What do you all think?

    Funny story: I was looking at an alternative energy book from the early 80’s. In it was a double pane window that has a 2 inch gap between the panes. A hole in the top and a hole in the bottom was used inject or remove millions of tiny Styrofoam beads. The idea was at night you could fill up the window with beads like an ant farm. In the morning you could pull the plug and all the beads would pour out.…not as practical as good old window quilts, but sounds REALLY FUN.

    -----Wood Strapping/furring strips ---------------------------------------
    A few years ago before I knew the strength of the arcs I assumed I had to make internal arcs out of wood to insulate and frame; things became 1/2 the cost when I figured out the arc was able to support the interior finishes. I was planning on doing what you did with the 4x4’s spanned the length of the building. I was also planning on having the strapping 4’ or 12’ or 8’ apart. So I don’t have to cut my drywall (wink wink nudge nudge).

    If I do drywall it will I have to add braces/framing to support the drywall?

    With the old insulation I wanted more R-value then the 4 inches could provide…I haven’t done the math with the polyurethane foams. What R-value are you getting?

    If I needed more of a gap what might work well without adding the weight of 6x6s? anyone?

    Can anyone suggest a light, very sustainable or recycled substance instead of lumber for this?

    -----Painting the Roof -------------------------------------
    I really don’t see any benefit to painting a nice reflective totally inert substance like the aluminum/galvanized steel/alloys these are made of. But I fear local codes and neighbors will want me to.

    ----Hoisting up Arcs-----------------------------------------
    I am planning on using 30feet 7.5inch width arcs that are 14feet 11inches high. Would these be easier to hoist up fully assembled?
    Assuming a perfect circle and not an ellipse, using 22.5 feet as your radius and 15.3 as mine. The relative mass of each arc should be ((15 x pi x 2)/(22 x pi x 2))= about 0.4624. Am I going to be able to do it the way all the steel companies claim? How many friends will I need to feed and booze?

    To prevent the dragon flexing could I attach 2 complete arcs and then hoist it up?

    Ohh yeah…I did plan on using 14 gauge steel also. I am not in a snowy part of Colorado… but I figured the inspectors would feel better about me hanging lumber and drywall from it if I used the thick stuff.

    -----Angle Iron Seam---------------------------------------------
    I was told by more than one of the steel firms that a connecter exists that can be up to 6 inches tall curved to the exact arc of the building and can be used to fasten endwalls. If I get a picture of one I will post it.

    -----Re: We may add an additional 2 foot arch-----------------
    I am planning on having an overhang as well. Not much rain here but too much sun in the summer. It shouldn’t lessen my solar heating much in the winter due to the low solar angle.

    I will sort thorough all my links, remove the WW2/Nissen stuff, and hopefully post some resources related to modern Quonsets.

    Thanks again will. And thanks for hosting this thread. I look forward to your feedback and any info from others.

    • Re: Even more Questions from Pete

      Sun, March 19, 2006 - 11:14 AM
      Hey Pete,

      Just found this post.

      We found that the only thing we feel 100% comfortable with was the spray foam insulation.

      It is very expensive - but that is offset by the reasonable price of the building.

      After a year of living with it, buidling, surviving all types of weather, we are more confident than ever with our decision. The other methods you'll see, (the Pioneer site, etc.) are only recommended for use to insulate a building, which will be used for storage, etc. NOT for residential use.

      Any condensation you allow (up behind the insulation) will wreak havoc for years to come - slowly multiplying the problems on every level. The foam also adds a great deal of strength and has many other benefits which become evident over time.

      We found the most amazing place on the planet for windows and doors. 33 buildings full - all brand new at cents on the dollar. I think I sent you that info already, but if I didn't, email me.

      That's all I have time for now. construction awaits...

      • No, you sent the contact info for the window place. But if is drive windows back from Washington...I will brake some. I was hoping someone would see that post who knows of a glass factory or discount window dealer in Colorado, Wyoming, or Nebraska.

        (i am sold on your type of insulation. I have to do some research on whether i should inject it behind the drywall or spray it on first. Also a little research on the chemistry)
        • Will,
          I was originally hoping to do what you did in these photos:

          I have been working all day on the inside finish of the arcs. 4’ spacing or 2’ spacing. 2’ is too heavy and 4’ isn’t close enough to drywall without extra bracing (typically 16”). Should I spray on the foam and add the finish later or put on the finish and inject the foam behind? Injecting will give me more R-value but I will have to do the drywall and electrical first or use electrical conduit and that is expensive. Grrrrrr.

          I am trying to find lighter and cheaper 4x4s. What do you think of using square PVC or Polyethylene (HDPE) tube. Like:

          But if I use hollow PVC I can make it double as electrical conduit…umm…electrical conduit that I drill screws into….maybe not?

          -What do you think of these alternative materials?
          -Will 2’ spacing decrease the R-value of the insulation too much?


          P.S. My dad came up with a great finish idea:
          Space out 4’ with the 4x4s. Run 1x2s or 0.5x2s across them to create perfect curved arcs. Then rent a u-haul and bring tongue and groove pine from the Midwest.

          then run the pine panels parallel with the 4x4s nailing into the 1x2s.
          I wish he lived closer…(free labor ;)
          • Re: Icynene/polyurethane foam and spray stucco

            Sat, March 25, 2006 - 11:19 PM
            I was researching how many holes i would need to drill to use 4x4 galvanized hat channel instead of 4x4 lumber to hold up dry wall when a friend suggested the following. "just spray on the insulation then spray on interior stucco..." I didn't know stucco could be sprayed and i didn't realize it could stick to foam? (Apparently there is an interior stucco …not the old heavy stuff)

            -Would this work? can the foam support a spray on stucco?

            I took a passive solar class today at the National Renewable Energy Lab.
   it was not as in-depth as i hoped. I wanted to learn how to model and predict what i needed for thermal mass and windows, no luck, but I got some good ideas out of it..

            I keep thinking how buying a (crappy) existing (boring) house would keep my stress down and would let me focus on grad school. I keep getting nervous because this is a BIG responsibility. But this project is CALLING me and it makes so much since to start NOW.
            • Hey Pete

              Mon, March 27, 2006 - 2:00 PM
              I took a quick look at your post.
              As far as the strapping, I feel that the pvc options would probably be very expensive, and not really give you any benefits. The arch structure has an incredible amount of strength, so the weight is really NOT an issue. We found a fellow who mills and sells rough lumber, MUCH cheaper than any lumber yard. The actual dimensions do not really need to be very consistant or exact, so any type of 'degrade' lumber will do.

              We put our strapping up at 4' centers and that seems to work well for attaching hardboard to, which will take a curve, is light and relatively inexpensive. It can be covered with virtually anything later to give a variety of finishes.

              After a great deal of research, this is what we decided to go with.

              You can spray all sorts of different materials over the foam, including 'lightweight' stucco etc. There are all sorts of spray application products out there, but we found them all too expensive. We also wanted to avoid the interior profile of the steel, and just get to a smooth interior first.

              That's all I have time for now,


      • Re: Even more Questions from Pete

        Fri, March 31, 2006 - 10:22 AM


        What do you think of the feasability of putting insulation and/or earthbagging on the outside of the arches, and stuccoing the outside to seal it?

        Would leaving the inside bare metal cause a condensation problem if the outside were heavily insulated (perhaps even partially earth-sheltered) to provide a heat-sink?

        • Re: Even more Questions from Pete

          Mon, April 3, 2006 - 12:23 AM
          Hey G,

          I don't really feel qualified to answer this question - I don't want to mislead you.

          I only know that condensation (if any) will occur where the warm surface comes in contact with the colder one. If you end up with even the smallest amount of condensation, ideally, you want to be able to see it as that awareness will affect your reaction. If there IS condensation, and no way to ger rid of it, it may start an ugly cycle of events including mold, etc.

          Not good.

          We decided to play it safe, spend the $ and never have to think about it again.

          If you are thinking about what you mentioned in your post, I would recommend meeting with a very expereinced h.v.a.c. person before you go too far.

          hope that helps,

          • Regret from Pete

            Sun, February 4, 2007 - 9:58 AM
            Well the heating models were kicking butt, the cost was 1/3rd that of a home in Fort Collins, it was all great. But getting the land in Fort Collins was hard, and getting the bank to co-operate without first owning the land was a problem. The real problem is I took a job teaching science 7 days a week from 6am to 10pm and took a pay cut. Originally I thought 3 months in the summer would be enough time but really the school demands a month of training, go figure? I regret to inform you that I bought a home and will be putting the Quonset on hold. I will still tinker with designs and hope it is my next home, but I don’t have the time to invest in it now that I am a teacher. Thanks for your info Will. Keep me in the loop. Pete
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    Re: Quonset Questions & Answers from/for Pete

    Sat, June 24, 2006 - 2:14 PM


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