Ceiling spray foam insulation in Strathmore is work on the ceiling planes of a mostly young stock, and what is distinctive is not how they were built but the pressure difference across them on an open site.
A plane with a pressure difference across it
Every Strathmore ceiling separates warm air below from a roof space above, and every ceiling has openings in it. What decides how much moves through those openings is the pressure across them, and on an exposed lot that pressure is considerably higher and considerably more variable than in a sheltered town. So the same hatch, the same fan housing and the same top plate leak more here than the identical detail elsewhere, which is why sealing the plane is worth more in this town than depth ever will be.
Snow leaves one slope and banks on the other
On an open lot the snow that lands on a roof does not stay where it fell. It is scoured off the windward slope and deposited on the lee one, which means the two halves of the same roof spend the winter in different conditions. The bare slope loses heat directly to the sky, and the loaded slope carries a blanket that keeps its deck warmer and holds meltwater at the eave. That is why ice appears on one side of a Strathmore house and not the other, why the complaint is asymmetric, and why looking at a roof from the street on a February morning tells you more about the ceiling underneath it than any amount of discussion.
Where the bathroom fan actually discharges
This is worth checking on every house of this era and it is wrong more often than anybody expects. A fan is ducted up into the roof space, and the duct is supposed to run to a vent through the roof or the soffit. On a great many houses it stops short, discharges into the attic, and every shower for fifteen years has been putting warm wet air directly above the ceiling. On an exposed site the consequence is worse than usual, because the moving air in a scoured attic carries that moisture across the whole roof space rather than letting it leave near where it entered. It is a cheap thing to correct and it belongs before any decision about insulation.
In July the same plane works in the other direction
A ceiling is discussed as a winter surface and on an unshaded lot it is not one. There are no mature trees over these roofs, so the deck takes full sun from morning to evening and the roof space above a Strathmore ceiling runs far hotter than the yard outside. That heat arrives in the rooms below through the same openings the winter air uses, which is why a house that is difficult in January is frequently also difficult in July and why sealing the plane pays in both directions. It is also the reason the bedrooms under a poorly sealed ceiling are the rooms people complain about in summer.
Ceiling Spray Foam Insulation Strathmore: Common Questions
Would more depth help? Less than sealing would, and on an exposed lot considerably less.
Why is only the vaulted room cold? That is the one section that cannot be reached from the attic, and it needs establishing first.
What is the worst spot in these houses? Where the ceiling meets the space over the garage. It is rarely looked at and rarely sealed.
Size the assembly with the R-value calculator, then get a free Strathmore quote. More on Ceiling Spray Foam Insulation Alberta.