Spray polyurethane foam (SPF) is a type of insulation that is applied by spraying a liquid mixture that expands into a foam. SPF has some advantages, such as high R-value, air-sealing capability, and resistance to moisture. However, SPF also has some potential issues that you should be aware of before using it. Some of the issues with SPF are:

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• Health risk: SPF contains chemicals called isocyanates, which can cause skin, eye, and respiratory irritation, asthma, sensitization, and allergic reactions². Some people may be more sensitive to isocyanates than others, and there is no safe level of exposure for sensitized individuals². SPF also emits volatile organic compounds (VOCs) during and after installation, which can affect indoor air quality and cause headaches, nausea, and other symptoms¹. SPF installers and occupants should wear proper personal protective equipment (PPE) and ventilate the area well during and after application
   

• Installation errors: SPF requires careful and precise application by trained and certified professionals. Improper installation can lead to problems such as poor adhesion, shrinkage, cracking, off-gassing, odor, and reduced thermal performance. SPF can also damage electrical wiring, plumbing, and HVAC systems if not applied correctly. SPF installation should follow the manufacturer's instructions and industry standards and be inspected by a qualified third-party.

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• Cost and maintenance: SPF is more expensive than other types of insulation, such as fiberglass or cellulose. SPF may also require periodic maintenance, such as re-coating, to prevent deterioration and UV damage. SPF may also be difficult to remove or repair if needed and may not be compatible with some roofing or siding materials.

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• Environmental impacts: SPF is made from petroleum-based chemicals, which have a high embodied energy and carbon footprint. SPF also contributes to ozone depletion and global warming through the use of hydrofluorocarbons (HFCs) as blowing agents. SPF may also contain flame retardants, which can leach into the environment and cause ecological and health problems. SPF is not biodegradable and may end up in landfills or incinerators, where it can release toxic substances.

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• SPF is not a one-size-fits-all solution for insulation. It has some benefits, but also some drawbacks that should be carefully weighed before choosing it. You may want to consider safer and more sustainable alternatives to SPF, such as mineral wool, cellulose, or cork. You can also use the Safer Choice label to find products that meet EPA's criteria for human health and environmental safety.