Quonset spray foam insulation in St. Paul is work on the oldest steel building on the yard. In this district the arched buildings were going up long before anybody put up a modern engineered shop, and a great many of them are still standing and still in daily use, which is a testament to the shape. They were built as cold storage for machinery and grain. The ones we are asked about have been promoted to heated shops, and nothing about the original design anticipated that.
The curve rules out everything except a sprayed layer
There is no wall and no roof in an arch, just one continuous surface, and it is corrugated. Nothing cut to size fits it. Batt cannot be held against it, rigid board cannot follow it, and framing a stud wall inside it either eats the usable width or leaves a wedge-shaped void at every point around the curve. Foam is sprayed directly onto the inside of the ribbing, follows the geometry exactly, bonds to the steel and seals every corrugation as it goes. That is why the question on these buildings is almost never which material, only how thick and what goes over it.
The condensation is the reason most owners call
A bare arch is a single sheet of steel between inside and outside. It reaches outdoor temperature immediately, and anything warm and moist in the building condenses on it. In northeastern Alberta the cold holds for months with no thaw partway through to clear it, so frost builds on the inside of the arch from freeze-up and then releases in a few warm spring days. It falls on the equipment, the grain or the workbench underneath. Closed-cell foam at about two inches is its own vapour barrier and, adhered directly to the steel, there is no cold surface left for moisture to find and no gap behind it for air to carry moisture into.
The end walls are a separate building
The arch is steel. The end walls are usually wood-framed, with the large door in one of them, and they were built and rebuilt by different hands over the decades. They have their own sheathing, their own leaks and their own depth, so they get quoted as their own assembly. The junction where the end wall meets the curve is the hardest line on the building to seal and the one most worth doing properly, because it is a continuous opening running the full arc on both ends.
The base, the floor and the ground
An arch meets the ground at a knee that is often set in or on a concrete curb, sometimes on nothing more than a footing strip. Frost drives deep here and stays deep, so that knee sits in cold ground all winter and conducts. Foam carried down to the curb and across the knee is part of the job; so is a decision about the floor, because an uninsulated slab or a gravel floor under a heated arch is a loss the walls do not touch.
What goes over the foam, and the fire question
Where a Quonset is being used as an occupied workspace, a thermal barrier over the foam is a code requirement rather than a finish preference, and on a curved surface that means a coating rather than drywall. That needs to be in the quote from the start. It is also worth planning the lighting and any hanging loads before spraying, because drilling into a cured foam layer afterward means repairing the seal every time.
Who you are dealing with
We do Quonset spray foam insulation St. Paul ourselves. We scope and quote it, we book it, and our own installers spray it -- one company, one point of contact.
Quonset Spray Foam Insulation St. Paul: Common Questions
Why does it frost on the inside and then rain in spring? Because the single skin of steel goes to outdoor temperature and indoor moisture freezes on it. With no mid-winter thaw here, it accumulates all season and lets go at once.
Can a Quonset be insulated any other way? Not practically. Nothing cut to size follows a corrugated arch, and framing inside it either loses the width or leaves voids all the way round.
Do the end walls get done at the same time? They should, and they are quoted separately because they are a different assembly. The joint between the end wall and the arch is the detail that matters most.
How much does Quonset spray foam insulation cost in St. Paul? It is priced by sprayed area and thickness, with the arch and the end walls as separate quantities and any required coating over the foam as its own line.
How do I choose a Quonset spray foam contractor in St. Paul? Ask how they seal the joint where the end wall meets the arch, and what finish goes over the foam if people will be working in there. Both answers show whether they have done one of these before.
Size the assembly with the R-value calculator, then get a free St. Paul quote. More on Quonset Spray Foam Insulation Alberta province-wide.