Closed-cell spray foam: Flexibility for complex architecture

Îlot Rosemont provides 193 housing units for low-income centres, while, functioning as an administrative centre with nearly 300 employees.

One project, one product

Typically, during the specification process, the design team will have to look for multiple products from a variety of manufacturers and suppliers to cover all aspects of a project’s building envelope. For a complete building envelope, engineers need to specify products that provide insulation, air sealing, and moisture control, among other things. This can be a time-consuming process at the design stage, where different properties and how each product will interact at the installation stage must be considered.

Traditional insulation methods, such as fibreglass, are less dense and susceptible to humidity and moisture build-up and, therefore, require additional products to be considered and used in pursuit of the perfect building envelope. Mineral wool also needs a vapour barrier on the warm side of the assembly, so there is a higher risk of condensation when it is installed in the cavity, compared to SPF.

During construction, with rain and snow, materials such as fibreglass and mineral wool, depending on where they are installed, can absorb water and humidity trapped in the assembly. This is not the case with SPF. Traditional insulation methods may require specifying and installing an additional vapour barrier, in the form of, say, polyethylene plastic sheets, which is neither time- or cost-efficient. It is also wise to install an air barrier with traditional insulation, to further improve the quality of the building envelope, however, this can lead to increased time and cost commitments, which can interfere with and extend project deadlines.

For the building engineer in charge of the building envelope, it would be much simpler to specify one product that performs the duties of insulation, vapour barrier, and an air barrier all in one. There are spray foam solutions on the market that perform all three tasks. For example, some have an aged thermal resistance RSI-value of 1.94 for 50 mm (1.9 in.), and act as a vapour barrier at 32 mm (1.2 in.). Performance, in this context, means it needs to meet the requirements of ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials, for vapour resistance and be below 60 ng (nanograms), meet CAN/ULC S741 for air barriers, be below 0.02 L/(s·m²) (0.004 cfm/sf), and meet CAN/ULC S770 for thermal resistance.

This is a leading value aspect of closed-cell spray foam insulation, which can function as all three within a building envelope. Engineers save time by specifying one product for three different purposes and, later down the line, installers can save time as well by installing one product which contributes to a premium building envelope.
On a larger scale, developers can be confident in the speed and simplicity of a single product serving multiple functions, as they will be able to meet building code requirements faster than normal and potentially make up for delays. Lastly, the cost of SPF per square metre (square foot) can be reduced when using large quantities. For large building projects, the cost of installing SPF will be less than the cost for smaller projects, but costs always depend on the project and many other variables.

For engineers and installers, closed-cell spray foam will be easier to respectively specify and eventually install, when compared to traditional insulation materials such as fibreglass, mineral wool, cellulose, and polystyrene. Overall, closed-cell spray foam is more flexible, cost-efficient, insulating, and multi-purpose—all properties which will prove valuable for a wide array of applications and projects. These benefits are made increasingly clear when one looks at problems plaguing the construction industry. A Canadian survey revealed 75 per cent of owners had over-planned budgets on their project, and 77 per cent were late. If one element can solve multiple problems at once, it can further help expedite timelines.2

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