Closed-cell spray foam: Flexibility for complex architecture

by arslan_ahmed | April 21, 2023 4:00 pm

[1]

By Maxime Duzyk

The last thing an architect or building engineer wants is a limited vision. The last thing a developer wants is delayed delivery and cost increase. The last thing a building owner wants is a costly, uncomfortable, unsafe building space. Hydrofluoroolefin (HFO) spray foam insulation can solve these concerns, with its flexibility, ease of installation, and complete moisture, air, and vapour barrier capabilities. Architects and building engineers can be confident that no matter the angle, thickness, or complexity of a given wall, roof, or foundation, an HFO closed cell spray foam can fufil their vision and avoid the need for redesigns during the construction process.

Spray foam contributes to both immediate construction needs and long-term building results, as it meets several building standards. The product standard for an HFO closed cell spray foam is CAN/ULC S705.1 and its install standard is CAN/ULC S705.2. Some products also comply with CAN/ULC S101 for tall buildings. Thermal resistance is tested in accordance with CAN/ULC 770-09; fire compliance for the product in accordance with CAN/ULC S102; air barrier compliance for the product in accordance with CAN/ULC S741 and for the air barrier system in accordance with CAN/ULC S742.

For architects and building engineers, deploying the perfect building envelope can sometimes come into conflict with the original vision, goals, and projected timeline for a given project. Walls drawn by an architect may be too thin or may curve too much to be properly insulated using traditional solutions, and specifying certain types of insulation can delay project timelines due to unfavourable weather or temperature drops, complex construction sequencing, etc. Developers are always striving to manage as many factors as possible in the pursuit of accurate and efficient project timelines. However, elements such as the weather and unique architecture could have consequences on building codes, timely construction, or key project milestones.

[2]

Spray foam insulation: Interior and exterior

Spray foam insulation can be installed on the outboard of the exterior sheathing or in an interior application, such as in the stud cavity. Installation can be performed quickly and at very low temperatures, allowing contractors to effectively insulate projects, sequence their work, and meet deadlines. At 25.4 mm (1 in.), spray polyurethane foam (SPF) insulation can be installed by one person at a rate of 46 m² (500 sf) per hour. Other products may take more time.

Builders confirm, compared to other insulation systems, they can save up to six weeks of construction time, depending on the assembly. Further, closed-cell spray foam insulation has a comparatively higher RSI-value than other forms of insulation, allowing walls to be thinner and more complex or curved, as the architect may have originally intended.

The total RSI-value always depends on the total thickness installed but some HFO products offer a 1.94 RSI-value for 50 mm (1.9 in.), meanwhile others can offer a 1.49 RSI-value for 50 mm (1.9 in.). The flexibility and resulting versatility of closed-cell spray foam insulation is particularly valuable when it comes to designing, specifying, and building the building envelope, especially when it comes to roofing.

When a roof is being designed, whether it will be a flat roof, cathedral roof, or something less traditional, there are many features and details to be considered. Roofs could contain skylights, recessed lights, plumbing vents, chimneys and, most importantly, air and vapour barrier continuity.

Air and vapour barrier continuity can be understood as building envelope continuity—ensuring the building envelope extends to exterior walls, foundations, below slab, and properly accounts for various roofing styles and design elements. Neglecting proper building envelope continuity for roofing can lead to several issues that will affect performance and durability. Roofs lacking proper insulation or air and barrier continuity can be at risk of moisture retention, which can eventually lead to mould growth; this could damage other aspects of a structure and be costly to rectify. A poorly insulated roof can also lower a building’s energy efficiency, as heating and cooling efforts can be made less effective it is able to leak through the roof with ease.

Closed-cell spray foam insulation can solve all these issues, without placing extra burdens on architects, building engineers, contractors, and developers. It can simplify the specification process as it can provide a continuous building envelope. This means a sole product can serve multiple functions for a project, and an experienced insulation contractor can manage all aspects of a building envelope quickly and efficiently.

[3]

Case study: Îlot Rosemont

Recently, the Office Municipal d’Habitation de Montréal (OMHM) undertook a social housing project: Îlot Rosemont. Îlot Rosemont provides 193 housing units for low-income centres, while, functioning as an administrative centre with nearly 300 employees.¹ During its development, the project had fallen behind schedule, and its unique architecture posed further challenges. Some of these features included: two divided wings, a 10-storey wing on the west side, an eight-storey wing on the south side, a V-shaped support column two-storeys high, supporting the building with connecting beams, and many beams on the third level, including five with post-tensioning work. Another feature of this project is the slab on a steel deck over a large area on level two, and a concrete structural slab on level three over the entire surface of the building. The local climate of Quebec also affected the project’s completion schedule, and the thermal resistance also needed to be high. SPF ensured the building envelope requirements were met.

Îlot Rosemont made use of closed-cell spray foam and was able to get back on track quickly, without compromising on the architectural vision, and providing unparalleled comfort for the future residents of the project.

[4]

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

[5]

The benefits of closed-cell spray foam insulation

Typically used in colder climates, closed-cell spray foam insulation outperforms traditional insulation by providing an air, water, and vapour barrier in a single component. It can be installed on either side of the building envelope, interior and exterior, and has one of the highest RSI-value. Open-cell spray foam installtion is superior to traditional insulation materials as an air barrier, and is often used to insulate interior walls and roofs to improve acoustic performance.

Closed-cell spray foam performs its functions at a high level, granting increased energy efficiency and indoor air quality (IAQ) for future residents. Due to its expanding nature when installed, closed-cell spray foam can fit any space, as it expands to fill in tricky crevices and spaces which traditional insulation materials may struggle to address. Since it expands to fit these spaces, a complete air and vapour barrier is easily, continuously, and consistently formed, without the need for additional materials and insulation methods to bolster its effectiveness.

The comparatively high thermal resistance of closed-cell spray foam means developers incorporating it into their building envelope will be met with builds that are more energy efficient, mould and mildew resistant, comfortable for end users, and more environmentally friendly. Some manufacturers have product-specific environmental product declarations (EPDs) demonstrating the much lower global warming impact SPF has when compared to any other type of insulation. In the warmer seasons, dwellings are kept cooler and retain air conditioning efforts for longer periods, while in the winter, the warmth is conserved, and heating elements can be run less frequently. Both result in energy and cost savings for building owners, and help contribute to Canada’s long-term goal to reach net-zero emissions by the year 2050.³

Closed-cell spray foam also helps combat radon buildup, an odourless, tasteless, colourless gas which can be deadly at certain concentrations. It is essential for developers to do everything they can to mitigate radon build-up; closed-cell spray foam can help with this. Due to its ability to form a continuous soil gas barrier, spray foam insulation can prevent radon from entering a structure through the under-slab and foundation, when properly installed. Radon travels primarily through the air, so an effective air barrier can be a great way to ensure residents and users of a building are kept as safe as possible. When it comes to preventing radon diffusion, some independent recognized laboratory testing with certain HFO spray foam brands demonstrate it can perform up to 829 times better than polyethylene sheets at only 50-mm (1.9-in.) thick.⁴ In addition, the thickness of spray foam makes it more resistant to damage and punctures while construction is taking place, preventing the need for replacement and reinstallation. Some HFO spray foams are also Canadian Construction Materials Centre (CCMC) certified with respect to radon protection, such as CCMC evaluation 14280-R, which confirms the high quality of the product for this application.

[6]

Due to the way spray foam insulation expands and hardens, it can also benefit structures in other ways. First off, spray foam insulation absorbs water incredibly slowly and dries out quickly when a water source is removed. Depending on the brand, spray foam insulation also functions as a flood-resistant insulation material, rated FEMA Class 5, for buildings located in at-risk areas. It is recognized and referenced as such in the 2021 Federal Flood Damage Estimation Guidelines for Buildings and Infrastructure by Natural Resources Canada. Its rigid final state contributes to the racking strength of the structure it has been installed in, allowing square and rectangular walls to better withstand external forces, such as wind, seismic activity, and thermal expansion and contraction. Structures insulated with closed-cell spray foam enjoy higher wind load resistance, which can be especially advantageous for those living in particularly breezy areas. The rigidity of spray foam is backed by incredible durability, making it an excellent choice for insulating flat or cathedral roofs. This type of insulation will not sag or lose its properties over long periods of time, meaning roofs will remain strong and perfectly sealed for decades without the need to replace or maintain the insulation.

When it comes to fire compliance, it can sometimes be difficult to get assemblies in line with fire codes. Certain spray foam insulation assemblies are tested for fire in accordance with CAN/ULC S101, Standard Methods of Fire Endurance Tests of Building Construction Materials. These assemblies are UL listed (EW25 and EW24).

[7]

 The installation process

One of closed-cell spray foams greatest strengths is the speed and ease of its installation. Some spray foam brands will have a network of elite contractors, ready to expertly deploy spray foam for a variety of projects. The National Building Code of Canada (NBC) and the installation standard for the SPF product, CAN-ULC-S705. 2 (closed-cell) and CAN/ULC S712. 2 (open-cell), mandates polyurethane foam installers to be certified to install the product. Some brands put high emphasis on safety and personal protection, helping installers make it a priority on-site. They also have service representatives and offer the latest training information through training/education programs to assist installers exhibit safe behaviour, which can help achieve a zero-incident job site.

The speed of the installation process means even if weather conditions are unfavourable, the insulation can still be sprayed, left to dry, harden, and be ready for the next step of construction in-between periods of intense weather. Once the foam is installed, it becomes water-resistant and is not at the same risk of damage, say, fibreglass insulation is.

Since spray foam can expand its initial volume in seconds up to 30 times, it is able to quickly fill gaps, small joints, and crevices. If building engineers, architects, or developers have questions, certain spray foam insulation suppliers will have experienced technical teams ready to address questions and concerns. There are also third-party software available to certify applicators. A survey, commissioned by Procore Technologies Inc., a construction management software provider, and conducted in 2021 by international research firm IDC, revealed that within the construction industry, projects are, on average, 70 days late, compared to their original estimate.⁵ Therefore, choosing a provider who is prepared to go the extra mile is important.

Some suppliers have developed proprietary installation and assembly methods, designed specifically to facilitate spray foam application, regardless of temperature or wind conditions. Spray foam can be installed completely from the interior with innovative techniques, such as cutting the thermal bridge of a wall’s studs by filling the gap between the exterior sheathing panel and the studs. The size of this gap can change depending on the insulation values a project needs to achieve and is created with Z-bars installed directly on the exterior face of the studs before the exterior sheathing panels are installed.

The spacing and size of Z-bars will change depending on the structure and the cladding. This method eliminates potential delays due to weather conditions, as the spray foam insulation is applied completely from the interior. It also reduces rental costs associated with scaffolding, hydraulic elevators, associated logistical work, and accident risks. The walls can be insulated as they are built, speeding up installation and requiring fewer workers overall. Some manufacturers have completed detailing and testing, such as fire compliance and U-value assembly results. The mechanical and electrical (M&E) components can be installed before or after the SPF. If a perforation needs to be made after the SPF installation to run a duct or a wire, it can easily be sealed back with canned foam. This will also save heating costs for construction projects taking place during Canada’s harsh winters.

[8]

Insulation in any architectural feature

While traditional forms of insulation must be cut to size from pre-fabricated panels, or loosely blown into cavities, spray foam can effectively insulate even the most complicated of structural features (e.g. thin walls, multi-faceted roofing, curved foundations, complex slabs). The previously mentioned case study, Îlot Rosemont, had architectural features such as many slanted and thin exterior walls. Due to spray foam insulation’s high thermal resistance, thinner walls are not an issue, and can save construction costs. Roof framing can be done with thinner framing members, as spray foam provides the same thermal resistance as traditional insulation materials with less thickness.

Irregularly shaped spaces and tight corners can abound when spray foam insulation is specified for projects, so architects can execute on beautiful, creative, boundary-pushing designs which enhance the visual appeal of communities and provide gorgeous interior working and living environments. Beyond beautiful architecture, the completely sealed building envelope creates unparalleled comfort for occupants and contributes to green building standards and sustainability mandates put forward by the federal government.

Conclusion

In an industry plagued by ever-increasing project deadline delays and costs, labour shortages, doing whatever possible to expedite construction and lower expenses is important. Closed-cell spray foam can solve issues facing today’s architects, building engineers, and developers, with speedy installation, simplified specifying, high-quality benefits to building strength and comfort, safety standards, and reduced environmental impact. Closed-cell spray foam does more with less. Altogether, it acts as insulation, an air barrier, a vapour barrier; and is flexible in how it can be applied to structures.

Notes

¹ See Îlot Rosemont, huntsmanbuildingsolutions.com/en-CA/tech-library/ilot-rosemont[9].

² Read further about the results of the Canadian survey, www.renewcanada.net/5000088747-2/.[10]

³ Learn more Canada’s goal to reach net-zero emissions by 2050 www.canada.ca/en/services/environment/weather/climatechange/climate-plan/net-zero-emissions-2050.html[11].

⁴ See this CCMC Canadian code compliance evaluation to learn more about radon protection. www.huntsmanbuildingsolutions.com/en-CA/sites/en_ca/files/2023-02/CCMC%2014280-R_e.pdf[12]

⁵ For more information, visit at www.idc.com[13].

[14]Author

Maxime Duzyk is the director of building science and engineering with Huntsman Building Solutions. He holds a background in architecture and has been in the spray foam industry for the last 12 years. Duzyk is involved with different building envelope committees and associations in North America, such as CSC, SFC, SPFA, CCMC, and ULC Standards.

Source URL: https://www.constructioncanada.net/closed-cell-spray-foam-flexibility-for-complex-architecture/

---