Central Alberta has a lot of quonsets that have been standing for decades, and a building that has spent thirty winters dripping on itself is usually carrying some corrosion. Quonset spray foam insulation in Red Deer therefore begins with a question about the steel rather than about the insulation: what condition is the shell in, and what has the condensation already done to it.
Foam over rust does not stop rust
This is the point worth being blunt about. Spraying over corroding steel makes it invisible, not inactive. Where the rust is still active it continues under the foam, out of sight, and the first anyone knows about it is a hole or a failing fastener years later. Worse, foam does not bond reliably to loose scale, so the material can let go from exactly the areas that were already the weakest. Preparation is not an upsell on these buildings, it is the difference between a repair that lasts and one that hides a problem.
What a proper look at the shell involves
Going along the arch and finding where water has been running and sitting, which on a quonset is usually the lower third of the curve and along any seam. Checking fasteners for movement. Looking for perforation rather than surface staining, because those are different problems with different answers. That inspection happens before anything is quoted, and it sometimes ends with us saying the shell should be repaired first.
Surface rust and structural rust are not the same conversation
Light surface corrosion can be cleaned back and treated, and then the building is a perfectly good candidate. Steel that has thinned or perforated is a structural question and belongs to somebody who repairs buildings, not to an insulation contractor. Being clear about which one you have is more useful than a confident quote that treats both the same way.
Why the arch has to be sprayed rather than lined
A quonset has no stud bays and no flat surfaces. Batt has nothing to sit in, and rigid board cannot follow a curve without leaving voids behind it - and a void against cold steel is where the water collects. Foam takes the shape of the arch and bonds to it, so there is no cavity to condense in, and it is the air barrier and the insulation at the same time.
Getting the condensation to stop
Dripping stops when the interior surface is no longer colder than the dew point of the air touching it. Ventilating a bare arch moves air around but leaves the cold surface exactly where it was. Removing that surface is what actually changes the building, which is why the foam goes direct to the shell rather than behind a liner.
Quonset Spray Foam Insulation Red Deer: Common Questions
Can you spray over rust? It should not be done. Active corrosion continues underneath and the foam does not bond reliably to loose scale, so it can let go from the worst areas.
How do I know if my quonset is worth insulating? Surface corrosion that can be cleaned and treated is fine. Steel that has thinned or perforated is a repair question first.
Where does the rust usually start? The lower part of the arch and along the seams, and on the older Red Deer arches that band is the first place to look, where condensation has been running down and sitting for years.
Estimate the thickness with the R-value calculator, then get a free Red Deer quote. More on Quonset Spray Foam Insulation Alberta province-wide.