SPF Insulation’s Silent Threat to Health

Updated: January 14, 2024

There are numerous insulation products with various applications on the market. The Spray Polyurethane Foam (SPF) is one insulation product that was introduced in the 1960’s with the development of new equipment designed specifically for processing spray foam liquid compounds. SPF’s market has grown to 1.5 billion dollars as of 2022.

“Spray polyurethane foam is becoming a mainstream material, but its performance and hazards are both highly debated.“

– Tristan Roberts from BuildingGreen

Spray Polyurethane Foam (SPF) is a type of insulation used to effectively fill cavities. It has 2 liquid chemical sides:

Side A: Isocyanates

Side B: Polyol resin, flame retardants, and amine catalysts

Side A and B react to expand up to 30-60x their liquid volume when sprayed in place. This expansion can fill cavities and produce a high thermal insulating value with virtually no air infiltration.

THE CONCERNS

Although this product insulates better than almost all other insulations per inch, it is not readily biodegradable and has additional health concerns.

Toxicity of SPF Insulation

During Installation – The combination of Side A and Side B chemicals creates hazardous fumes and thus requires robust PPE during installation.

(See the EPA’s warning about misleading marketing leading to improper protection and application).

After Installation – Once the foam has fully expanded and dried, manufacturers say it is inert. However, if the chemicals are not properly mixed, they may not react fully and can remain toxic after installation. There is also evidence that the foam does not hold up over time, allowing off-gassing to continue as it disintegrates.

Problems with Side A – Isocyanates:

Leading chemical cause of work-related asthma
Contact dermatitis, skin and respiratory tract irritation, sensitization
Skin and inhalation exposures may lead to respiratory responses

Problems with Side B – Polyol blend:

Amine catalysts in SPF may be sensitizers and irritants that can cause blurry vision (halo effect)
Flame retardants, such as halogenated compounds, may be persistent, bioaccumulative, and/or toxic chemicals (PBTs)
Blowing agents may have adverse health effects (not to mention a high GWP)
Surfactants may be linked to endocrine disruption

If a material has to be installed while wearing a protective suit and respirator, shouldn’t we question its long-term health impacts?

WHAT CAN YOU DO?

Spec cellulose, mineral wool, wood fiberboard or fiberglass for thermal insulation.
Consider alternative insulations on the market like hemp wool.
For air sealing and vapor control: use membranes, sheathing, and tapes.
Avoid closed-cell spray foams made with hydrofluorocarbon (HFC) blowing agents. They have a high global warming potential (GWP).
If spec’ing SPF is unavoidable, require applicators to wear adequate personal protective equipment during and after installation.

ABOUT THE AUTHOR:

Deborah Buelow, AIA, WELL AP, is the founding architect of Cedar Architecture, a boutique design firm specializing in high-end residential projects, wellness spaces, and educational facilities. Cedar was founded with the ethos of fusing architecture with nature, aiming for a harmonious blend that offers not just aesthetic appeal but also practical, sustainable and health-centered benefits.

Deborah holds a Bachelor of Architecture degree from Iowa State University and continued her academic journey at the Massachusetts Institute of Technology (MIT), where she earned her Masters of Science in Architectural Studies with a focus on Urbanism. Working in New York, Boston and Washington DC region, she gained extensive experience in both large-scale federal and institutional buildings as well as small-scale infill urbanism, giving her a deep understanding of architectural needs at various scales.

At the community level she is actively involved in the City of Alexandria’s Healthy Homes Initiative. She also serves as an active member of the Maryland State Accessory Dwelling Unit Policy Task Force. Both of these volunteer positions address issues of health, sustainability, and accessibility for homeowners around the region. Deborah served as the president of the AIA Potomac Valley chapter in 2020 and remains an active board member, currently chairing the Committee on the Environment (COTE). She also holds a board position at AIA Maryland.

Through her years of experience, community involvement, and leadership, Deborah has emerged as an influential voice in architecture, advocating for design that is as thoughtful about its impact on human health as it is about its impact on the landscape. Through her practice she is determined to show what architecture can achieve when it engages with the broader issues facing society today.