All building materials, when installed to create a building envelope assembly, work interactively as a system.  The purpose of which controls the movement of heat, air, and moisture. When not properly designed or installed, moisture can move through the building envelope.  This moisture condenses on cold surfaces that are below the dewpoint temperature or create high levels of moisture. Additionally, this moisture, at certain temperatures,  can provide the conditions necessary to promote the growth of mold and mildew.  Such moisture also requires the presence of organic food sources (paper, wood, bacterial dust, etc.)

Spray foam is not a source of food for mold, mildew, and bacteria.  However, organic dust can collect on the surface of the foam. In combination with moisture at the right temperatures, these organic dust can result in mold and mildew. Spray foam, like all insulation products, can result in mold and mildew problems in building envelopes that are poorly designed or constructed. Proper air sealing, as well as use and placement of vapor retarders, and sufficient levels of insulation are key to proper building envelope design.

During and immediately following spray foam applications, fumes and mists are generated that can be hazardous to your health. Access to the work area during this time should be restricted to personnel wearing appropriate personal protective equipment (PPE).  An example of PPE is a respirator.  Furthermore, this area should be restricted to those whose job responsibilities require them to be in the area.

The application of spray foam can produce hazardous levels of airborne chemicals during and just after installation. These chemicals will degrade into non-hazardous compounds in a few hours when combined with moisture in the air. Because of these short-term airborne levels, re-occupancy of the work area by other trades or building occupants is typically 24 hours. However, specific re-occupancy time may vary depending on the type of material, the volume of mists and fumes generated, building size and rate of ventilation. Your contractor and their supplier can recommend re-occupancy times based on job-specific conditions.

Spray foam is an ideal product for insulating and air-sealing existing homes. Furthermore, spray Foam creates energy-saving unvented attics and crawlspaces that seal against air leakage.  It brings under-insulated and leaky HVAC ducts inside the conditioned space of the building. Additionally, spray foam insulates and air-seals band and rim joist areas where the framing meets the home’s foundation.

During application, spray foam, like most site-applied building materials, releases small amounts of chemical compounds into the air. Each manufacturer provides a time for re-occupancy after completion of the application. Spray Foam materials and coatings may emit odors that may be noticeable by some people.  However, with proper ventilation, these odors should subside.

Several spray foam products were independently tested (ULe GreenGuard, CAN-ULC 774, CA 01350) for the release of volatile organic compounds.  After the prescribed cure periods, measurements found no significant levels. Furthermore, one study performed by the American Medical Association assessed the toxicity of a number of foam plastic insulation products.   It concluded that fully-cured polyurethanes present no toxicity problems for humans (the Journal of The American Medical Association, Vol. 245, No. 3.)

Closed-cell foams, by its nature, resists water absorption and FEMA approved them as a flood-resistant material. Open-cell foams may absorb and retain liquid water at varying rates. Moreover, it is important to consider the different properties for each foam type for each application.

There are two general categories of SPF insulation materials; open-cell, low-density (a.k.a. ‘half-pound foam’) and closed-cell, medium-density (a.k.a. ‘two-pound foam’). Both foam categories provide excellent insulation and air sealing. Although both utilize almost identical chemical reactions, there are some inherent physical property differences.  These differences often determine the choice of product for a particular project.

Open-cell Spray foam

Open-cell spray foam has an open-cell structure where the cells fill with air. The open-cell structure renders soft, flexible foam, with a density of about 0.5-0.8 pounds per cubic foot. Still, the air is the primary insulation medium in Open Cell Spray Foam, fiberglass, and cellulose. These insulations work by reducing the natural air movement within these materials. Thereby, reducing the ability of the material to conduct heat. The R-value per inch of open-cell foam typically ranges from R3.6 to R4.5 per inch.

Unlike fiberglass and cellulose, the fine cell structure of Open Cell Foam makes it air-impermeable at certain thicknesses. The air-impermeability of Open Cell Foam qualifies it as an air-barrier material.  It dramatically reduces air leakage through the building envelope, significantly lowering the building’s heating and cooling costs. Open Cell Foam, like fiberglass and cellulose insulations, is moisture-permeable. It may require the installation of a vapor retarder in colder climates.

Closed-Cell Spray Foam

Closed-cell spray foam has a closed-cell structure which yields a rigid, hard foam, with a density of 1.8-2.3 pound per cubic foot, and previously demonstrated a structural enhancement in certain framed buildings. These smaller cells trap an insulating gas, called a blowing agent. This blowing agent has a lower thermal conductivity than still air and increases the R-value. Typical R-value per inch of closed-cell foam ranges from R5.8 to R6.9* per inch, which makes it a great choice in applications with limited clearance.

Like Open Cell Foam, Closed Cell Foam is also air impermeable at certain thicknesses and can qualify as an air-barrier material. The closed-cell structure of Closed Cell Foam makes it water-resistant and is the only spray foam that can be used where contact with water is likely (e.g., below-grade concrete walls, in contact with the ground, or on the exterior side of the building envelope). At a thickness of 1.5 inches, Closed Cell Foam has moisture permeance typically less than 1.0 perms and no additional vapor retarder is required for most applications.

No, after 24 hours, there will be no toxic chemicals or gasses present.  Be sure to check with your installer, but the only thing you should need to be worried about is keeping your pets out of the attic for the first day after installation.  Typically pets don’t have access to this area anyway, but you do want to make sure they aren’t able to chew on the expanded foam and possibly ingest it.

Spray Foam Attic Insulation is just as safe as the foam pillow you lay your head on each night.   The reality is that spray foam is a type of plastic with millions of enclosed miniature gas bubbles.  It’s an ideal product for roofing and is optimized for durability and thermal insulation.