HFO-blown spray foam to prevent air leakage, improve waterproofing

by arslan_ahmed | September 22, 2023 11:00 am

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By Maxime Duzyk

The growing demand for energy-efficient and sustainable building solutions drives building engineers and architects to search for innovative and cost-effective ways to optimize insulation. One such cutting-edge insulation technology is hydrofluoroolefins-blown (HFO-blown) spray foam insulation, a high-performing, eco-friendly alternative to traditional insulating materials such as fibreglass or mineral wool. The true strength of HFO-blown spray foam insulation lies in its versatility, with its ability to function as an effective air barrier and waterproofing solution, and as a high-performance insulation.

This article will dive into the many benefits of HFO-blown spray foam insulation, from its unparalleled R-value, flexibility, how it can function as an air barrier and waterproofing solution, and how it alleviates pain points often experienced by building professionals, architects, and contractors.

Overview of HFO-blown spray foam insulation

HFO-blown spray foam insulation is a two-component, polyurethane-based foam applied using specialized spray equipment. The foam is created from a combination of hydrofluoroolefin (HFO) blowing agents and other chemicals, resulting in a lightweight, high R-value insulation material. The HFOs used as blowing agents have a significantly lower global warming potential (GWP) than traditional hydrofluorocarbon (HFC) blowing agents, making them a more environmentally friendly choice. In the past, HFC-blown spray foams cultivated a somewhat negative reputation, due to their high GWP. The GWP difference between HFC and HFO blowing agents is a 99.9 per cent reduction.¹ In addition, HFO blowing agents have zero ozone depletion potential (ODP), making them a more climate-friendly option in more ways than one.

Some high-quality spray foam insulation products even offer a product-specific environmental product declaration (EPD), which is a rare sight seeing as most products are backed by industry average EPDs. Through this EPD, top-tier products are shown to possess a GWP of 39 per cent lower than the industry average for HFO spray foam, which is up to 96 per cent lower than HFO blowing agent extruded polystyrene (XPS), and 77 per cent lower than high density mineral wool. These numbers comparing the GWP potential consider everything, from the manufacturing of the products to their end of life, which is estimated at 75 years.

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Designing and specifying buildings for the future is not just about reducing carbon emissions during construction, but also for the lifetime of the building, and in its actual day-to-day use. For all sorts of projects, this translates to lowered energy usage by residents and users, as they enjoy more efficiently insulated buildings, leading to reduced operational carbon emissions for decades to come.

Upon application, closed-cell spray foam rapidly expands to fill gaps, cracks, and other openings, forming a seamless, continuous layer of insulation. As it cures, the foam hardens and adheres to the building’s structural elements, effectively creating a monolithic building envelope that is both energy-efficient and resistant to moisture, air infiltration, and thermal bridging. The ability of spray foam to fill gaps, cracks, and other openings so efficiently greatly contributes to its effectiveness as an air barrier.

Air barrier capabilities

One of the most significant advantages of HFO-blown spray foam insulation is its ability to serve as an air barrier. Traditional insulation materials, such as fibreglass or mineral wool, are often unable to prevent air infiltration effectively, leading to energy loss and higher utility bills.

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HFO-blown spray foam insulation, on the other hand, forms a continuous, airtight seal, preventing air leakage and maintaining a consistent indoor temperature. Spray foam provides a complete air barrier and unparalleled insulation values.

Canada’s neighbour, the U.S. Department of Energy (DOE) notes, when correctly installed, closed-cell spray foam insulation “can yield a higher R-value than traditional batt insulation for the same thickness, and can fill even the smallest cavities, creating an effective air barrier.”²

What makes an effective air barrier is not only defined by its ability to completely envelope a structure and fill small nooks and crannies, but its air permeance. Most building codes require an air permeance of less than 0.02 L/s·m² (0.04 cfm/sf) at 75 Pa (1.5 psf) to be considered an air barrier, and closed-cell spray foam insulation regularly tests lower than this figure, surpassing many building code regulations across North America.

This exceptional performance helps reduce energy consumption, saving homeowners and commercial building operators from heating and cooling costs while providing a more comfortable indoor environment. According to the DOE, air leakage can account for 30 per cent or more of a home’s heating and cooling costs,³ therefore, working to ensure buildings have proper ventilation without air leakage is important when it comes to new builds or retrofit projects aiming to be more energy efficient.

Waterproofing solution

Beyond its air barrier capabilities, HFO-blown spray foam insulation also functions as a waterproofing solution. Due to its ability to fill and seal gaps, cracks, and openings, the insulation creates an impervious barrier that effectively blocks moisture and prevents water damage.

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HFO-blown spray foam insulation’s closed-cell structure means it is inherently resistant to water absorption and mould growth. This is in stark contrast to materials, such as fibreglass or mineral wool, which can retain moisture and contribute to mould growth and structural damage.

Moreover, HFO-blown spray foam insulation is always installed with a drainage layer. This reduces the risk of water infiltration and for the exterior finish to be 100 per cent water-resistant. The component layers of these exterior insulation and finish systems (EIFS) do need to consider a water-resistive barrier over the substrate to prevent moisture from infiltrating the system. They also require more frequent inspections due to potential water infiltration issues, unlike HFO-blown spray foam.

The problems with barrier EIFS all emanate from water intrusion. These complications can include moisture accumulation in the wall cavity, subsequent wood damage, and in more advanced circumstances, mould growth, and the infestation of pests such as carpenter ants or termites.

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Closed-cell spray foam’s water resistance goes beyond mould and vapour build-up, as case studies have demonstrated its value in the event of an actual flood. In Montreal, Quebec, a basement insulated with closed-cell spray foam flooded and was eventually drained. When it was drained, the basement drywall was damaged and had to be replaced, the studs had absorbed moisture, but the spray foam insulation was in perfect condition. Once the water was removed, the insulation and the structure did not need to be replaced, saving homeowners massive costs.

It is possible to waterproof the exterior of a building’s foundation with a polyurea coating or bituminous coating, which, when combined with HFO spray foam insulation, will help protect the basement. However, for existing buildings, this can be a huge effort, as it may require excavation all around the building.

For existing buildings, it is instead best to use materials which are inherently water-resistant. Then, if the basement does get flooded, the material can be kept and will only need to be dried—for example, utilizing metal for framing instead of wood, or using spray foam insulation. Some high-quality spray foam insulation products are rated Class 5 by the Federal Emergency Management Agency (FEMA), which means it can survive getting wet, being dried out, and then being cleaned after a flood. Further, they are also mould-resistant and can be GREENGUARD gold certified to ensure high indoor air quality (IAQ).

Ecological impact and sustainability

In today’s environmentally conscious world, the ecological impact of building materials is a key consideration for building professionals. HFO-blown spray foam insulation is an eco-friendly choice due to its low GWP blowing agents, which are less harmful to the environment than traditional HFC blowing agents. This means, not only is HFO-blown spray foam insulation more energy-efficient than other insulation types, but it also has a lower carbon footprint.

Further, the material’s high R-value, air barrier capabilities, and water-resistant properties can help building engineers and architects achieve Leadership in Energy and Environmental Design (LEED) certification and other green building standards. By incorporating HFO-blown spray foam insulation into their designs, building professionals can demonstrate their commitment to sustainability while providing clients with a high-performing and cost-effective insulation solution.

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In terms of building operations, a considerable portion of expenses is attributed to energy consumption. Consequently, selecting a product with a lower GWP and greater energy efficiency than its competitors is crucial; as building operations energy consumption has an impact on GWP. In fact, a building insulated with a specific HFO can save 110, 000 kg (24,2508 lbs) of CO2 in a lifespan of 75 years.

Closed-cell spray foam insulation stands out as the top choice in the insulation sector for constructing eco-friendly and energy-efficient homes. Although closed-cell spray foam contributes to greenhouse gas (GHG) emissions during the installation process—due to the utilization of diesel generators to power the spray-foam installation equipment—its initially higher embodied carbon emissions are offset compared to fibreglass insulation in mere four years.

Looking forward, adjustments to the installation process could further reduce the ecological impact of spray foam insulation and serve to cement its position as a climate-conscious choice when it comes to designing a building envelope.

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 Simplifying and solving multiple problems with spray foam insulation

Building engineers and architects often face the challenge of specifying multiple products to address different aspects of the building envelope, such as insulation, air barriers, and waterproofing. HFO-blown spray foam insulation provides an all-in-one solution, offering the advantage of being able to tackle these diverse functions with a single product.

This versatility simplifies the design and construction process, reducing the need for multiple materials, complex installation procedures, and compatibility issues that can arise when using various products. Further, HFO-blown spray foam insulation’s ability to be applied to a wide range of substrates, including concrete, steel, and wood, makes it an ideal choice for a variety of building types and applications.

HFO-blown spray foam insulation also offers additional benefits, such as improved structural integrity and racking strength. Its closed-cell structure can dampen vibrations and reduce the transmission of sound through walls and floors, leading to quieter and more comfortable living and working spaces. In addition, the foam’s strong adhesion properties can increase the structural strength of walls and roof assemblies, providing an extra layer of protection against natural disasters, such as hurricanes and earthquakes.

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Real-world examples and comparisons

To further illustrate the advantages of HFO-blown spray foam insulation, here are some real-world examples and comparisons.

Residential retrofit

In a study conducted by the Building Science Corporation, a house built in 1907 was retrofitted with HFO-blown spray foam insulation. The result was a massive reduction in CFM50—due to multiple upgrades, including spray foam. CFM50 is the metric used to determine air tightness of a given structure using blower door testing. The entire home, including the basement, scored 7729 CFM50 before work was carried out, and it scored 1802 CFM50 after retrofits were completed. For this project, the estimated annual energy savings will reach 48 per cent.

The home’s comfort and IAQ were significantly improved as well.⁴ Spray foam insulation was used throughout the home, in the basement, attic, paneling, and so on, and installation was simple due to the flexible nature of spray foam insulation’s installation process.

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Commercial/institutional building

Baie-Saint-Paul Hospital is an example of an air barrier and waterproofing project. The architectural consortium, which designed the project, and the general contractor used spray foam insulation in an effort to receive LEED certification.

Today, the hospital’s air barrier system meets energy efficiency requirements. By using spray foam insulation, the hospital has a value of R-27 for the insulation alone, which exceeds all requirements for all building types.⁵ Including the complete wall assembly, the insulation value is approximately R-30. Further, all the insulation is on the exterior side of the wall, keeping thermal bridges to a minimum, which improves the wall’s effective R-value. The heating and air conditioning costs are also therefore greatly reduced, resulting in a much lower building use cost.

Cold storage facility

Cultures H. Dolbec Inc. in Saint-Ubalde, Quebec went with an exterior spray foam insulation approach for their moisture-controlled warehouse, using state-of-the-art technology fully automated for potato conservation. The mandate for their 50 x 92 x 9.6 m (164 x 301 x 31 ft) design-build, with a surface area of near 5,202 m² (56,000 sf) of the building envelope, including wall and roof insulation, interior partition wall, and the doors.

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The building was constructed to offer a spacious interior and a high energy efficient building envelope to reduce the operation costs. Storage of large potato crops requires a controlled climate environment and must be moisture-free. Spray foam insulation sprayed in the walls and ceilings allows for those desired climate conditions and minimized condensation inside the storage building. By having spray foam insulation installed from the exterior of the building, it created a monolithic insulation and air/vapour barrier, removing the risk for condensation, addressing thermal bridging, and creating a rainscreen for exterior water penetration.

Historical building renovation

In the autumn of 2000, Patenaude Consultants Inc. conducted a condition survey case study of a wall in the Lofts Corticelli Complex in Lachine, Quebec.⁶ The Lofts Corticelli Complex consists of three, four-storey buildings (blocks A, B, and C). The buildings are clad predominantly with solid clay bricks (two or more courses) and aluminum punch windows. The wall sections consist of 12.7 mm (0.6 in.) gypsum board with aluminum foil backing on steel furring; 44.5 mm (1.75 in.) fibreglass batt insulation, 19 to 25.4 mm (0.9 to 1 in.) polyurethane foam insulation, and two or more courses of brick cladding. This type of retrofitted wall was insulated from the interior using spray-applied polyurethane foam insulation.

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Originally built for industrial purposes, the buildings were converted for residential use in 1984. As part of the conversion work, polyurethane foam insulation was sprayed over the interior surface of the solid masonry walls. An insulation-filled wall framing system, finished with gypsum board sheathing, completed the wall assembly. The physical analysis for the spray foam applied met the CAN/ULC S 705.2-98 standard requirements for cohesion and adhesion properties, and had a good cell structure and normal density. In general, the spray-applied polyurethane foam insulation was in good condition, with good adhesion to the masonry. The polyurethane foam had been applied as a continuous system, and no visible cracks in the material were noted. The success of the masonry insulation retrofit at Lofts Corticelli is primarily due to adequate control of air and moisture flow across the masonry.

In all these examples, HFO-blown spray foam insulation showed its strengths: unparalleled performance in terms of R-values, cost savings for the end-user, waterproofing abilities, and an overall lowered ecological footprint.

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Conclusion

HFO-blown spray foam’s ability to function as an air barrier, waterproofing solution, and high-performing insulation material sets it apart from other traditional options. The material’s low ecological impact, unmatched versatility, and numerous additional benefits further solidify its position as a comprehensive, cost-effective solution for modern building design.

By incorporating HFO-blown spray foam insulation into projects, building professionals can not only enhance the energy efficiency and durability of their buildings, but also provide clients with an environmentally responsible choice that contributes to a more sustainable built environment.

As building codes and green building certifications become more stringent, the adoption of HFO-blown spray foam insulation will likely increase. In Canada, for example, the federal government signed the Canadian Net-Zero Emissions Accountability Act into law in June 2021, which represents Canada’s commitment to a 40 to 45 per cent reduction in GHG emissions by 2030, and net-zero GHG emissions by 2050.

Choosing building materials that possess lower GWP has numerous benefits, such as energy efficiency, air sealing, waterproofing, and structural integrity improvements, and racking strength—all making it an attractive option for professionals looking to deliver long-lasting, high-quality building solutions to their clients. It is also important to note that spray foam insulation’s lower GWP is determined only in relation to its function as insulation. This means the GWP of the air barrier and waterproofing solution that would have to accompany other forms of insulation is absent in a building insulation with spray foam, further reducing the environmental impact.

It is essential for building engineers and architects to stay informed about advancements in insulation technology, such as HFO-blown spray foam insulation, to create innovative, environmentally friendly, and energy-efficient building designs. As HFO-blown spray foam insulation continues to gain popularity in the building industry, this versatile, high-performance material will play a significant role in shaping the future of sustainable and energy-efficient building solutions.

Notes

¹ Read the report, “HFO- and HFC-based Spray Foam Compared to Water-blown Systems,” polimaris.com/wp-content/uploads/2020/11/honeywell-blowing-agents-spray-vs-water-blown-systems-brochure.pdf.

² Learn more about different types of insulation by visiting, www.energy.gov/energysaver/types-insulation.

³ Read about air barriers, www.energy.gov/energysaver/air-sealing-new-home-construction.

⁴ Learn more about this retrofit case study,
www.buildingscience.com/project/brookline-ma-three-story-victorian-partial-deep-energy-retrofit-case-study.

⁵ See the Baie-Saint-Paul hospital, www.pomerleau.ca/en/project/baie-saint-paul-hospital.

⁵ Visit to learn more about this moisture-controlled facility, www.patatesdolbec.com.

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Maxime Duzyk is the global director of building science and engineering with Huntsman Building Solutions. He holds a background in architecture and has been in the spray foam insulation business for the last 13 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/hfo-blown-spray-foam-to-prevent-air-leakage-improve-waterproofing/

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