Fort McMurray carries an unusual share of multi-unit and shared accommodation for a city its size, and shared accommodation makes sound the complaint that never goes away. Open-cell spray foam is the material that addresses it. It is also the material most likely to be specified into the wrong assembly here, so the boundary matters as much as the benefit. Open cell spray foam insulation in Fort McMurray belongs on interior partitions and nowhere else.
The acoustic case
At roughly 0.5 lb per cubic foot, open-cell stays soft and open-structured, and that is what absorbs airborne sound. Closed-cell at 2 lb is denser, harder and a worse acoustic performer despite costing more. On a demising wall, a corridor wall, a mechanical chase or a bedroom partition, the half-pound product is doing the job the dense one cannot.
Why it stops at the interior line
Open-cell is vapour-permeable and it takes on moisture rather than shedding it. In a climate with winters this long and this cold, the vapour drive from a heated interior toward the exterior runs hard for months. Put a permeable, absorbent foam into an exterior wall, a crawl space or against steel and you have built a place for that moisture to arrive and stay. Every assembly here that faces outside, sits below grade or is bonded to metal is closed-cell work, without exception. That includes the industrial buildings through Gregoire and MacKenzie, where the whole point is removing a cold condensing surface - something a permeable foam cannot do.
Where the money actually goes
In a vented attic, depth is cheap. R-38 is about eleven inches of open-cell or about six of closed-cell, and if the space is there the cheaper material reaching the same target is the better purchase. Housing across Timberlea, Thickwood, Eagle Ridge and Parsons Creek was built to a range of standards and vintages, so the sensible quote looks at each assembly separately rather than applying one product to the whole building.
Code
Foam facing occupied space needs a thermal barrier - 12.7 mm drywall or an approved intumescent coating. Attics and crawl spaces reached only for service may use an ignition barrier. Open-cell falls under its own CAN/ULC standard; medium-density closed-cell is the S705.1 material. On multi-unit and commercial occupancies the authority having jurisdiction should be confirmed before the specification is fixed, because the requirements move with occupancy classification.
Off-ratio foam matters more where people sleep
Spray foam is a two-component product mixed at the gun, and if the ratio is wrong the chemistry does not complete. Off-ratio foam can keep off-gassing well after it should have cured, which produces a lingering odour and a re-occupancy problem. In a single-family house that is an inconvenience. In shared or camp accommodation, where the building may be occupied continuously and people are sleeping in it, it is a much larger one. This is why the installer and the conditions matter more than the brand on the drum, and why re-occupancy timing should be agreed before the work starts rather than discovered afterwards.
Open-Cell Spray Foam Insulation Fort McMurray: Common Questions
Why use the lighter foam in shared accommodation? Sound. On a demising wall, a corridor wall or a bedroom partition it outperforms the denser product at the thing it is actually being asked to do, for less money.
Can it go in an exterior wall here? No. The vapour drive in this climate runs hard all winter, and a permeable, absorbent foam in an exterior assembly gives that moisture somewhere to collect.
What about off-gassing in an occupied building? Foam is mixed at the gun and off-gasses while curing, so the area is cleared and ventilated and the installer gives a re-occupancy time. In continuously occupied accommodation that timing should be agreed before work starts.
Work out the thickness with the spray foam calculator, then get a free Fort McMurray quote. More on open-cell foam province-wide.