Tips for high-performance design: building envelopes with continuous spray foam insulation
Talk to a variety of building envelope product manufacturers to learn about their solutions for helping you meet your building performance goals.
May 19, 2021 By Maxime Duzyk
May 19, 2021 – The role buildings play in our cities and towns is becoming increasingly significant in our mission to lessen our carbon footprint and contribute to a healthier and better planet.
Building physics are evolving. We are seeing new techniques and technologies that foster the well-being of our large buildings and the people who reside and/or work in them. Building managers and owners are seeking to learn and implement strategies for high-performance building design.
Buildings need to co-exist with our needs. They should provide improved comfort levels by eliminating poor lighting, poor use of space, noise pollution, moisture and unpleasing temperatures. They should also strive to meet net zero standards by producing at least as much energy as they consume on an annual basis.
High-performance building design 101
High-performance buildings employ a variety of strategies… things like fresh air intake via a balanced heat/energy recovery ventilation system that continuously catches the thermal energy of exhaust air and keeps it inside the building. Also, high-calibre doors and windows that limit heat loss while allowing for daylight and passive solar energy; location factors that provide shading elements for the building and that protect from the sun when it’s not required; airtight envelope, elimination of thermal bridges and, of course, continuous insulation.
While there are various building certifications and rating systems one could strive to achieve, building managers and owners should first focus on the building envelope to control the transfer of heat and moisture throughout. This consists of the walls, roof and foundation of the buildings.
The building envelope is an absolute necessity for preventing air and moisture leakage, and reducing energy loss inside.
Spray foam insulation technologies take centre stage
To manage moisture and prevent warm or cold inside air leakage, spray foam insulation companies are leading with new closed-cell spray foam (ccSPF) hydrofluoroolefin (HFO) -based technologies.
Continuous insulation with a high R-value combined with no interruption from other building elements is essential for a high-performance building. This is where the effect of thermal bridging is considered with exterior insulation requirements being integrated with building codes. The cavity insulation can easily lose more than 50% percent of its effectiveness when the structure’s thermal bridging impact is calculated. That’s why selecting the right assembly and choosing the right SPF is key: you want to eliminate cold or hot spots throughout.
There are several advantages to using ccSPF in your high-performance building efforts:
1. First, not only can ccSPF reduce or eliminate thermal bridging, it is also boasts one of the highest R-values per inch of insulation products.
2. It acts as a water-resistive barrier (rainscreen), air barrier and vapour barrier.
3. Continuous insulation reduces the chance of moisture damage, because water is unable to condense on the inside face of the sheathing (source).
4. The more insulation is installed on the exterior of the structure, the lower the condensation risks. Many buildings now use a complete exterior insulation: the perfect wall as Joe Lstiburek from Building Science Corporation would call it. The four control layers (water, air, vapour and heat) are outside of the structure.
Keep in mind that the continuity and durability of a ccSPF install depend both on the product you choose with your builder or contractor, and the installer’s skills. It should only ever be installed by professionals who were trained by the manufacturer on that specific system.
(Some ccSPF has R-value at R-6/inch and also acts as the four control layers, and has the ability to expand and conform into the smallest crevasses, adhering to nearly all substrates, regardless of shape and texture.)
Closed-cell spray foam science
Today’s ccSPF technologies are high-performance building winners and act as an ultra-low global warming potential (GWP) insulation with superior spray-ability, adhesion and compressive strength. They meet compliancy with the Paris, Kyoto and Montreal Protocols, and have GWP 1 ratings (which is 99.9% lower than traditional blowing agents) and contain a total of 22% recycled plastic and renewable soya oil content.
Some manufacturers also have their own Environmental Product Declaration (EPD), which demonstrates their ccSPF incorporates less carbon than other types of insulation.
High-performance buildings are full of complexities… more than just orientation, they display “climate friendliness”, responsive to R-values, efficient in terms of mechanical systems, provide healthy indoor air, with glazing that effectively balances daylight and heat gain (source). In combination with ccSPF, they form an efficient, high-performance building.
Talk to a variety of building envelope product manufacturers to learn about their solutions for helping you meet your building performance goals. It costs nothing to ask, and can help you save a lot.
A note about radon
Did you know that closed-cell spray foam (ccSPF) can also be used to protect your building from dangerous radioactive radon exposure? According to a study commissioned by Health Canada, only 6% of buildings have been tested for radon.
Knowing that radon gets in through the soil, and soil gas intrusion happens mostly through air leakage, not just any sealant will do. A ccSPF product expands into the smallest crevasses and adheres to nearly all substrates, providing a continuous soil gas barrier. You can retrofit a building for radon mitigation by adding ccSPF as a control layer.
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 insulation business for the last 10 years. Maxime is involved with different building envelope committees and associations in North America like CSC, SFC, SPFA, CCMC and ULC Standards.
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