Quonset spray foam insulation in Hinton is most often asked about for a building holding a winter's feed, and the curved roof is exactly the shape that puts condensation back onto what is stored underneath it.
Everything that rises meets the same surface
In a rectangular building warm damp air rising off stored feed reaches a flat ceiling and spreads. In an arch it is funnelled to the crown, which is the coldest and most exposed line of the whole structure, and whatever condenses there runs a short distance back down the curve and drips onto the stack below. That is a geometry problem rather than a materials one, and it is why feed stored in a quonset here goes off from the top down rather than from the ground up.
A season's feed is a large amount of stored moisture
Hay and any baled feed carry water, they give it up slowly, and at this elevation they sit in the building for eight months doing it. That is a continuous supply of moisture into an unventilated building with a single cold surface above it. Nothing about the arch is at fault. The building is simply being asked to hold a moisture source for two thirds of the year with no route out, and it is worth understanding that before deciding whether the answer is insulation, ventilation or both.
What treating the arch actually changes
A continuous layer on the inside of the curve removes the cold surface, so the moisture stays as vapour rather than becoming water on the crown. It does not remove the moisture, which still has to leave the building. Where a Hinton quonset is treated without any deliberate way for that air to escape, the vapour finds the next coldest thing, which is usually the end wall or the base of the curve. Sealing and a designed exchange are specified together here or the problem moves rather than going away.
The base of the curve on both sides
Snow comes off an arch and lands in a bank along each side, so the lowest part of the steel spends the winter against a wet mass and the ground either side stays saturated into the summer. That is where these buildings fail structurally, it is invisible from inside, and it is checked before any money goes into the surface above it. Insulating over steel that is going at the ground line hides the deterioration rather than slowing it.
Quonset Spray Foam Insulation Hinton: Common Questions
Why does the top of the stack spoil first? The shape funnels rising air to the crown, and what condenses there drips straight back down.
Will insulating it fix that? It removes the cold surface. The moisture still has to leave, so ventilation gets specified with it.
What should we check before spending? The steel at the bottom of the curve on both sides, where the snow banks against it all winter.
Size the assembly with the R-value calculator, then get a free Hinton quote. More on Quonset Spray Foam Insulation Alberta.