Stack effect scales with the temperature difference across a building, and Fort McMurray applies the largest one in the province. Multi-family spray foam insulation in Fort McMurray is dealing with a force that is simply stronger here than it is anywhere else in Alberta.
The taller the building and the colder the day, the harder it pulls
Warm air inside a building is buoyant relative to cold air outside, and it rises and escapes at the top while cold air is drawn in at the bottom to replace it. The strength of that flow depends on the height of the building and the difference in temperature. Put a multi-storey building in a climate that reaches minus forty and the pressure difference becomes something residents can feel and staff have to manage.
What it looks like from inside the building
Ground floor entries that stay cold no matter how much heat is put into them. Top-floor units that overheat while the bottom of the building is under-heated. Doors that pull shut hard or resist opening. Corridors that never feel right. Those are not four separate problems, they are one, and adding heating capacity does not address the cause.
Sealing beats adding
The mechanism is air movement, so the fix is air sealing rather than insulation depth. Continuous sealing at the top and bottom of the building and around the vertical shafts is what reduces the driving pressure. Insulation added without addressing the leakage improves the wall while leaving the flow that is causing the complaints untouched.
Buildings that arrived in pieces
A meaningful share of multi-unit accommodation here was factory built and assembled on site. The joints between modules run through floors and ceilings as well as walls, and vertically stacked modules create a path straight up the building if those joints are not treated as part of the envelope. On a modular building, that path is the first thing worth checking.
Deep cold turns a small leak into a large bill
The difference between here and southern Alberta is not that the cold is worse on the worst day, it is that it does not let up. A leak that costs a few dollars a month in a milder city runs continuously for months here, and the same envelope defect produces a much larger number on an operating statement. It also changes what residents notice: at these temperatures a draught is not a comfort complaint, it is frost on the inside of a wall and ice at the base of a door. Owners here tend to already know which units are the problem ones, and that knowledge is usually the fastest way to scope the work.
Multi-family Spray Foam Insulation Fort McMurray: Common Questions
Why is the lobby always cold and the top floor too warm? That is stack effect, and it is strongest here because it scales with the temperature difference. Warm air leaves high in the building and cold air is drawn in low to replace it.
Will more heat fix it? No. The mechanism is air movement, so more heating capacity treats the symptom. Sealing the top, the bottom and the shafts reduces the pressure difference driving it.
Does a modular building need anything extra? The module joints. Stacked vertically, untreated joints create a continuous path up through the building, which is exactly what stack effect needs to work with.
Size the assemblies with the R-value calculator, then get a free Fort McMurray quote. More on Multi-family Spray Foam Insulation Alberta.