Two things work on a quonset in Lethbridge that do not work on one anywhere else in the province at the same intensity: the wind never really stops, and the temperature can reverse itself in an afternoon. Both act on the same weak point, which is the bare inside face of the arch. Quonset spray foam insulation in Lethbridge deals with both of those at once, and the curve makes it harder.
Chinooks are what make these buildings drip
The classic Lethbridge failure is not a cold snap. It is the thaw. Warm, comparatively moist air arrives fast over ground and buildings that are still deeply cold, and the steel shell of a quonset holds that cold long after the air temperature has climbed. Warm air touching cold steel condenses, and a building that was dry on Tuesday is raining on itself by Thursday. Because it is warm outside while it happens, the cause is regularly misread as a roof leak.
Wind finds the fasteners and the end walls
The arch itself is a good aerodynamic shape, which is why the pressure tends to concentrate at the end walls and along the fastener lines rather than over the roof. That is also where any mechanically-fixed insulation begins to work loose over years of buffeting. Foam bonded continuously to the shell has no fasteners to fatigue and no edges for the wind to get behind.
What foam changes
Closed-cell applied direct to the inside of the arch does three things at once: it removes the cold surface that the chinook air is condensing on, it seals the seams and fastener penetrations that the wind is driving air through, and it adds R-value. It is the same product doing all three, which is why the arch is one of the clearest cases for foam over any alternative.
Rust, end walls and the interior finish
- Deal with existing surface rust before foam is applied, not after.
- End walls are usually framed conventionally and are treated as a separate detail from the arch.
- A finished interior over the foam still requires the code thermal barrier for the building's use.
- Equipment stored in a sealed, insulated quonset stops going through daily condensation cycles, which is generally the reason the job pays for itself.
Quonset Spray Foam Insulation Lethbridge: Common Questions
What is different about a quonset here? Two things work on it at once - the wind, and the temperature swing. The curve makes both harder because there is no cavity to work with.
Does the shape make it more expensive? Not per board foot, but the surface area of an arch is larger than the footprint suggests, so the quantity is higher than people expect.
Can it be done while it is in use? The area is cleared and ventilated during application and the installer gives a re-occupancy time, so it is usually staged rather than done all at once.
Size it with the R-value calculator, then get a free Lethbridge quote. See quonset insulation province-wide or agricultural spray foam in Lethbridge.