Quonset spray foam insulation in Blackfalds is sprayed directly onto the inside of the arch. The quonsets around this town are the oldest buildings on most of the yards they sit on, and they are frequently the last agricultural structure on a piece of land that is changing around them.
An old shape on land that is changing around it
These went up decades ago on working farms, and a fair number of them now stand on parcels that have been subdivided, sold, or are sitting waiting for a decision. That matters before any technical discussion, because the right amount to spend on a quonset depends entirely on how long it is going to be there. It is worth asking a Blackfalds owner what the plan for the land is, and it is worth them answering honestly, because the answer changes the recommendation completely.
Why the shape rules out everything except a sprayed application
Assuming the building is staying, the geometry decides the product. There is no stud, no girt and no flat plane anywhere in the arch, so a batt has nothing to fasten to and a rigid board has to be cut into strips and fitted with a gap behind every piece. A sprayed application follows the curve and the corrugation in continuous contact with the sheet, leaving nothing behind it for air to move through. That is not a preference on this shape, it is the only assembly that works.
The end walls and the bottom edge
The arch is usually the sound part of these buildings. The end walls are framed conventionally, they carry the doors, and they have been cut about over the years to fit whatever needed to go in and out. The other weak point is the bottom edge, where the sheet turns down to meet a low curb or simply the ground, which is a continuous opening running the length of both sides and is normally hidden behind whatever is stored against the wall.
What condition the steel is actually in
Foam bonds to sound, clean, dry steel and to nothing else. On a building of this age the base of the arch is where corrosion starts, because that is where water sits and where equipment has knocked it over the years. That gets inspected before anything is quoted, and where there is significant corrosion or a sheet that has worked loose the money belongs in repair first. An honest assessment on one of these occasionally ends with a recommendation not to proceed at all.
Quonset Spray Foam Insulation Blackfalds: Common Questions
Why can we not just use batt? There is nothing flat to fasten it to. On a curve only a sprayed application stays in contact with the sheet.
Where do these leak? The end walls and the bottom edge, far more often than the arch itself.
Is spray foam worth it if the land may be sold? Then say so before anything is priced. It changes what is worth spending on the building.
Size the assembly with the R-value calculator, then get a free Blackfalds quote. More on Quonset Spray Foam Insulation Alberta.