A Quonset is the hardest building on any northern yard to insulate by conventional means and the easiest one to insulate with foam, and the reason is purely geometric. There is no wall and no roof, just a continuous corrugated arch from the slab on one side to the slab on the other, with no cavity, no flat plane and no framing to attach anything to.
Why nothing else fits the shape
Batt needs a bay. Rigid board needs a flat surface and a mechanical fastener. A hanging blanket needs something to hang from and then sags into the curve, where it holds moisture against the steel and comes loose a season later. Every one of those has been tried on arch buildings and every one of them ends up on the floor. Spray foam is applied as a liquid and expands in place, so it follows the corrugation and the curve, bonds to the steel across the whole surface, and ends up as one continuous layer with no laps, no fasteners and nothing to sag.
Condensation is why most owners call
A single skin of steel over a yard full of equipment, hay or supplies is a very efficient condensing surface. On a clear night the arch drops below the interior air temperature and whatever moisture the building holds comes out of the air onto the inside of the steel. On a curved roof it does not drip straight down either, it runs along the corrugation and lets go at the low point, which is why the wet patch on the floor never seems to be below anything in particular. Closed-cell removes the cold surface, and past about two inches it is its own vapour barrier, so there is nowhere for that moisture to go.
Snow load and the shape of the roof
An arch collects snow unevenly. In this country the snow arrives and stays from November to break-up, and on an arch it builds asymmetrically with the wind, deeper on the lee side. If the building is heated at all, warmth escaping through the uninsulated steel melts the layer in contact with it, which refreezes lower down the curve and adds an ice band that neither melts nor slides. Sealing the inside of the arch stops supplying the heat that drives that cycle. It is a structural benefit as well as a comfort one.
The ends are the weak point
The two end walls of a Quonset are usually framed flat, in wood, with a large door in at least one of them, and they are built after and separately from the arch. The joint between the flat end wall and the curved shell is almost always the leakiest line in the building, and it is where driven snow gets in. Foaming the arch and leaving the end walls and that joint untreated is a half job; the ends are a different assembly and they get their own treatment at the same time.
Heating only part of it
Few Quonsets here need to be heated throughout. The practical version is a sealed, insulated section at one end, partitioned off, for a workbench, a water system or anything that must stay above freezing, with the rest of the arch left cold and simply sealed overhead against condensation. That is a fraction of the board feet and a small fraction of the fuel, and it is usually what the owner actually wanted when they called.
One company, start to finish
Quonset spray foam insulation Slave Lake is quoted, scheduled and sprayed by us. Our own installers are on the job, and the number you are given is the number we stand behind.
Quonset Spray Foam Insulation Slave Lake: Common Questions
Can a curved steel building be insulated at all? Yes, and foam is the only common material that suits the shape, because it adheres to the corrugation instead of needing a cavity.
Water drips off our arch but the roof is sound. Why? It is condensation on the inside of cold steel, running along the corrugation and letting go at the low point. Sealing the inside face stops it.
Do the end walls need doing too? Yes. They are a different assembly and the joint where they meet the arch is the leakiest line in the building.
How much does Quonset spray foam insulation cost in Slave Lake? Board feet over the developed area of the arch, which is larger than the floor area because of the curve, plus the end walls. Clearing the building out so we can reach the steel is the other factor.
How do I choose a Quonset spray foam contractor in Slave Lake? Ask whether the end walls and that joint are in the quote, and whether they have sprayed an arch before. The curve is not difficult, but it is not the same as a flat wall.
Size the assembly with the R-value calculator, then get a free Slave Lake quote. More on Quonset Spray Foam Insulation Alberta province-wide.