Ceiling spray foam insulation in Rocky Mountain House is for the parts of a house with no attic above them: a vaulted room, an addition with a low-slope roof, the link between two roof levels. Out here the first of those is extremely common, because it is what people build when they have a view and some room.
The great room with the beams and the high ceiling
Houses in this district are frequently built around one large room with an open ceiling following the roof line. It is the reason people build here and it is also the hardest assembly in the house, because there is no attic above it to work in, no space to add depth and a large surface area at the warmest part of the house. Whatever that assembly has in it is what it will always have, so getting it right is worth more here than it would be on a standard plan.
A wood stove under a vaulted ceiling
Put a stove in that room and the effect is amplified. Warm air collects at the highest point and sits against the underside of the roof, which is exactly where the assembly is thinnest and where any gap in the ceiling plane is. That drives air and moisture into the roof structure harder than in an ordinary room. It is a good reason to treat this assembly properly rather than adding more heat, and it is another reason the sealing matters more than the depth number.
What fits in a rafter, and nothing more
The rafter depth is the entire space available. That means the only variables are how much resistance each inch delivers and whether the plane is sealed, which is what makes closed cell foam the assembly that suits the constraint. It gives the most per inch and it seals in the same pass rather than needing a separate air barrier occupying room that does not exist. Adding material is not an option here in the way it is in an attic.
Snow on a steep roof, and what it does at the eave
Roofs here are generally steep and they carry real snow. Snow slides, and where it stops is the eave, which is where any vented assembly takes its intake air. A vented shallow roof needs a clear path from that eave to the ridge, kept clear through a Rocky Mountain House winter. Where it can genuinely be maintained, venting is a legitimate choice. Where it cannot, an unvented assembly with foam in continuous contact with the deck is the honest answer, and it has to be built as one from the start rather than half of each.
Ceiling Spray Foam Insulation Rocky Mountain House: Common Questions
Can we add more insulation to a vaulted ceiling? There is nowhere to put it. The question is performance per inch and whether the plane is sealed.
Does a stove in the room change anything? Then warm air is collecting at the highest point against the thinnest assembly. Sealing matters more, not less.
Vented or unvented? One or the other, decided at the start. If the eave path cannot be kept clear, unvented is the honest answer.
Size the assembly with the R-value calculator, then get a free Rocky Mountain House quote. More on Ceiling Spray Foam Insulation Alberta.