Edmonton builds more secondary suites and mature-neighbourhood infill than most Canadian cities, and that is precisely the market where open-cell spray foam stops being the budget option and starts being the specified one. When two households share a building, the wall between them is an acoustic problem before it is a thermal one. Open cell spray foam insulation in Edmonton is specified for those shared walls, where sound is the objective.
Sound is a density-and-structure question
Open-cell is a low-density foam at roughly 0.5 lb per cubic foot. It stays soft and open, and that open structure absorbs sound energy better than a dense, rigid foam does. On a demising wall between suites, or between a basement suite and the house above it, that is the property being bought. Closed-cell would put a higher R-value in the same cavity and perform worse at the actual job.
The thermal numbers, honestly
Open-cell runs R-3.5 to R-3.8 per inch against closed-cell's R-6 to R-7. In a fixed 2x6 exterior cavity that difference is decisive and closed-cell wins. In an attic, where depth costs almost nothing, it is not: about eleven inches of open-cell reaches R-38, the same target six inches of closed-cell reaches, for less money. Edmonton's long heating season makes the attic number worth getting right, and it does not make the expensive material the right way to get there.
What it must never be used for
It is vapour-permeable and it absorbs moisture. In a city with deep basements and deep frost that rules it out below grade, in crawl spaces, on rim joists and anywhere bonded to steel. Roughly 59 percent of Edmonton homes predate 1991, and in that stock the basement is usually where the real work is - which is closed-cell territory. Using open-cell there because it quoted cheaper is how a job becomes a removal job.
Interior work in practice
Home offices, media rooms, laundry walls, plumbing chases and the wall against an attached garage are the everyday open-cell jobs. In newer areas like Windermere, Terwillegar, Summerside and Chappelle the partitions are already framed and the retrofit is straightforward; in mature-area infill the acoustic spec is usually written in from the start.
Foam facing occupied space still needs a thermal barrier over it - 12.7 mm drywall, or an approved intumescent coating - with an ignition barrier permitted in service-only attics and crawl spaces. Open-cell is covered by its own CAN/ULC standard rather than the S705.1 medium-density one.
Winter application is a real variable here
Edmonton's building season pushes a lot of interior work into cold months, and spray foam is sensitive to the conditions it is applied in. Substrate temperature matters: foam sprayed onto a surface that is too cold can fail to adhere properly, blister, or shrink back from the framing later. Shrinkage is the one that costs you the benefit you paid for, because a foam that pulls away from a stud has stopped being an air seal even though it still looks like insulation. Ask what the substrate temperature will be on the day and whether the space will be heated before the crew arrives - it is a fair question and a good contractor has a straight answer to it.
Open-Cell Spray Foam Insulation Edmonton: Common Questions
Why is it used in secondary suites? Because the wall between two households is an acoustic problem before a thermal one, and the softer open structure absorbs airborne sound better than a dense rigid foam.
Is it worse than closed cell? Different, not worse. It is the correct product for interior partitions and the wrong one for anything facing weather or ground.
Does it work in an exterior wall? Not in this city. Deep frost and a long heating season make the vapour drive relentless, and a permeable foam in an exterior cavity is a place for moisture to arrive and stay.
Size it with the spray foam calculator, then get a free Edmonton quote. More on open-cell foam province-wide.