Insulate my Quonset Hut, please.

December 2, 2012 5:17 PM

What's the best way to insulate my Quonset hut?

I have a (currently) unheated Quonset hut, about 30' x 30', with a couple of skylights and a conrete floor.

This summer, we set up a stage and used it as a rehearsal room, which was awesome. You can see it here. However we've been forced out by the cold. I'm thinking about insulating it and adding some heat so we can use it to rehearse in the winter too, and I assume this would also improve the acoustics, which are not bad when the big door is open, but are very ringy when it's closed.

What's the best option? Spray foam seems good but I worry that the expansion and contraction of the steel would compromise the adhesion. Today I was in a Q hut which had a kind of quilt-like insulation, but I can't find any details online. '

Anyone else insulated a Q hut? What did you do?

posted by unSane to home & garden (11 answers total)

because of the high temperature of the roof in summer, i wonder about the durability of spray foam in the long term. also, spray foam is expensive: what's your budget?

the cheapest thing is to blow in insulation. if you don't want solid walls, you can blow it in behind tyvek fabric. the idea would be to create something like a "puffy coat" of tyvek for the inside of the hut. cellulose, like goose down, tends to compress and settle to the bottom. so you would want to try and create thin horizontal pockets, like this jacket. you could try anchoring and tensioning braided wire from the side walls (if they can support the side stress) and then cutting and then gluing in pieces of foam to block off the channels of the quonset roof to keep the cellulose from settling down.

however you frame it, you need to make sure that the interior frame is very well air-sealed or moisture will get trapped between the insulation of the metal causing it to rust from the inside. that's one of the nice things about the spray foam: try calling a reputable installed and see what they think. ideally, you could do a layer of spray foam and then building the interior puffy jacket.
posted by ennui.bz at 5:53 PM on December 2, 2012

I'm not your professional engineer, and this is not professional engineering advice.

That's not a Quonet hut - that looks like a K-Span.

Which is great, because I actually have experience with these types of extruded steel buildings. You want to 1) seal any gaps, holes, joints or seams (exceot for the seams between the ribs, those should be sealed enough) and 2) provide an even layer of insulation to the structure

I would use a spray-foam insulation. You'll get better coverage, faster application, and no pesky seaming. For the acoustic benefits (and to obviate the need for a weatherproof foam), you should apply it to the interior. Especially with a building that curves.

Some sort of surface preparation will be necessary, but the thermal expansion of the steel is not a major concern.

These are industry pages, and you should check to see if the foam you want to use will adhere to the steel and coating of the structure:
Closed-Cell Spray Foam to Offer Significant Benefits to Metal Buildings
DIY Foam Insulation For Metal Buildings
FOMO FOAM. For the Better Metal Building
Can spray foam insulation work well with corrugated steel buildings?
posted by the man of twists and turns at 5:55 PM on December 2, 2012 [3 favorites]

Spray foam would be my first thought. I think the ones that were insulated back in the day had something like that, I seem to recall this sort of dense yellow foam (usually crumbling from age) lining the inside of them when we used to stay in them back in the Boy Scouts.

I would talk to a company that does corrugated metal construction and see what they do, maybe they could work something out for you or maybe point you toward someone who knows how to do this sort of thing.
posted by Scientist at 5:55 PM on December 2, 2012

Spray foam - you'd do best with a 2lb. density foam. At about two inches thick, it will act not only as insulation but as an air and vapor barrier. When you add heat to the space, think about how you will ventilate - you don't want to build a nice tight space and then suffocate.
posted by Crankatator at 6:05 PM on December 2, 2012

AMOTT, I got this building from futuresteelbuildings.com., but any steel building like this is colloquially referred to as a Quonset Hut round here. Thanks for the links -- they look great.

Scientist, there really aren't people who do construction of this kind of thing. They just dump a pile of metal and nuts and bolts and you're expected to somehow erect it yourself (I hired some guys who got into a terrible pickle because they tried to build it upside down -- I kid you not).
posted by unSane at 6:06 PM on December 2, 2012

(here's an image of the puffy jacket, it looks like they anchored little square brackets from the outside to create square shaped baffles (instead of long rectangles), which might be easier than what i was thinking though it does put more screws in your roof)
posted by ennui.bz at 6:08 PM on December 2, 2012

Yeah, that's what I saw today, Ennui. I liked it. It doesn't put more holes in because they're already there and they're just glomming onto the existing nuts/bolts. It's very neat and tidy and it's sort of defacto vapor barrier as well. I think I'll get that quoted against the spray. I bet it's a pain to install though.
posted by unSane at 6:18 PM on December 2, 2012

Perhaps you could talk to the folks at Future Buildings and ask them what the recommend? They may well already have a solution, you can't be the first person who has wanted to insulate one of their buildings.
posted by Scientist at 6:20 PM on December 2, 2012

That's a good idea, Scientist. The only problem with FSB is that they're basically a sales operation as you'll discover if you ever give them a call. Trying to get tech information out of them is always tricky, as they usually have some product they're trying to upsell you on. Don't get me wrong -- I actually like them a lot and the product rocks -- for example, they upsold me to skylights which are OMIGOD THE BEST THING EVAR -- but they're not the most independent source of advice on the planet, let me put it that way.
posted by unSane at 6:23 PM on December 2, 2012

I'm not sure off-hand which method would be best for you, but wanted to point out that the anchors in the picture ennui.bz linked may not add holes to your structure. To me, they look similar to those used to secure insulation to ductwork similar to those in the mechanical section[pdf] of this brochure. They may just be an adhesive and pin job that would greatly ease installation. Similar pins (same brochure, the first section) are welded on, which would provide a more secure hold while still not puncturing the roof membrane, but would be more labor-intensive.
posted by BevosAngryGhost at 8:00 AM on December 3, 2012

The way these steel building are constructed, they are riddled with holes at roughly 12" intervals which are used to bolt the sections together. So they probably just anchor right to those. I've done that myself with some of my shelving.
posted by unSane at 11:34 AM on December 3, 2012