Ceiling spray foam insulation in Lacombe is for the parts of a house with no attic above them: a back addition with a nearly flat roof, a room built into the roof slope, the link between two roof levels on a house that has been extended. On this housing stock there are more of those than most owners realise.
Roofs added at different times, meeting each other
A house that has grown over a hundred years has roofs from several eras joined together, and the junctions between them are where the trouble is. A low-slope roof over a back addition meeting the wall of the original two-storey house is the classic example: no space above it, no way to vent it properly, and a junction that has been re-flashed by several different people. That junction is where the attention goes, not the middle of the roof.
Depth is fixed by the rafter and nothing will change it
In an attic the answer to a cold room is more material. Here there is nowhere to put it. The rafter is all the space there is, so the only variables are how much resistance each inch delivers and whether the plane is sealed. Closed cell foam suits that constraint because it gives the most per inch and it seals in the same pass, rather than needing a separate air barrier occupying room the assembly does not have.
The room built into the roof
Older houses here frequently have a room in the roof slope with short walls at the sides and a flat section in the middle. That produces three different assemblies in one room, all of them shallow, all of them reached differently, and small triangular voids behind the side walls that were open on one day during construction and have not been reachable since. Treating the room properly means treating all three, and pricing only the flat part is how these jobs disappoint.
Vented or unvented, and on these roofs it is usually decided for you
A shallow roof is one or the other and it has to be built as one deliberately. A vented assembly needs a continuous clear path from eave to high point, and on a Lacombe addition that path is frequently interrupted by the original structure or by whatever the last builder did. Where it can genuinely be kept clear, venting works. Where it cannot, an unvented assembly with foam in continuous contact with the deck is the honest answer, and a roof that is half of each is what most failures turn out to be.
Ceiling Spray Foam Insulation Lacombe: Common Questions
Can we just add more insulation? There is nowhere to put it. In a shallow assembly the question is performance per inch.
Where does the work concentrate? The junction where a low roof meets the wall of the taller original house.
What does an upstairs room in the roof need? Then it has three assemblies, not one, and all three need treating or the room still disappoints.
Size the assembly with the R-value calculator, then get a free Lacombe quote. More on Ceiling Spray Foam Insulation Alberta.