Frequently Asked Questions

About Spray Foam

  1. What types of spray foam are there?
    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 are made using almost identical chemical reactions, there are some inherent physical property differences that often determine which product is chosen for a particular project.
  2. Does SPF emit volatile organic compounds after installation?
    During application, SPF, like most site-applied building materials, will release small amounts of chemical compounds into the air. Each manufacturer will provide a time for re-occupancy after completion of the application. SPF materials and coatings can also give off odors that may be noticeable by some people, but with proper ventilation, these odors should subside. Several SPF products have been independently tested (ULe GreenGuard, CAN-ULC 774, CA 01350) for release of volatile organic compounds, and no significant levels have been measured after the prescribed cure periods. One study performed by the American Medical Association, assessed the toxicity of a number of foam plastic insulation products and concluded that fully-cured polyurethanes present no toxicity problems for humans (the Journal of The American Medical Association, Vol. 245, No. 3.).
  3. What fire protection measures (thermal or ignition barriers) are required for SPF?
    SPF, like many construction materials, is combustible, and can ignite when subjected to heat or flame. For this reason, model building codes require that SPF materials (with some exceptions) must be separated from interior (occupied) spaces by a 15-minute thermal barrier, such as ½” gypsum board. In limited access areas like crawlspaces and attics, an ignition barrier may be permitted in place of a thermal barrier. Prescriptive thermal and ignition barriers are defined in the model building codes, and alternative coatings,coverings and assemblies may be used.
  4. How much does SPF cost?
    As a trade association, SPFA, by law, cannot provide information on material or installation costs. In general terms, the installed cost of SPF insulation is greater than that of fiberglass or cellulose insulations, but SPF provides many extra benefits including air barrier and vapor control, as well as improved structural performance. The installed cost of SPF roofing systems is competitive with other roofing systems. Free free to contact us for an estimate / quote for specific requirements.
  5. What are the structural benefits of closed-cell SPF?
    Because of its rigid nature and ability to adhere to many materials, closed-cell SPF (ccSPF) can provide structural enhancement to framed buildings. Racking strength of certain framed walls, as well as uplift strength of framed roof decks can be significantly increased with the addition of just 2-3 inches of SPF. For more information, please contact SPFA to obtain detailed reports.
  6. Is SPF suitable for residential retrofit insulation applications?
    SPF is an ideal product for insulating and air-sealing existing homes. SPF can be used to create energy-saving unvented attics and crawlspaces that seal against air leakage and bring under-insulated and leaky HVAC ducts inside the conditioned space of the building. In addition SPF, can be used to insulate and air-seal band and rim joist areas where the framing meets the home’s foundation.
  7. Should access to the work area be restricted during and immediately after spray foam installation?
    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), including respirators, and whose job responsibilities require them to be in the area.
  8. How soon can buildings be re-occupied after SPF installation?
    The application of SPF can produce hazardous levels of airborne chemicals during and just after installation. These chemicals, most notably MDI, 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 type of material, volume of mists and fumes generated, building size and rate of ventilation.
  9. Can SPF be used as an air barriers?
    Spray foam, when applied to certain minimum thicknesses (about 1.5” for closed-cell foam and 3.5-5.5” for open-cell foam) will form an air-impermeable, air-barrier material. When properly installed in a well-designed building envelope, SPF plays a key part in creating air barrier assemblies and systems.
  10. Can SPF be used with other insulations (Hybrid Insulation Systems)?
    Closed-cell SPF can be used in combination with other insulation materials such as fiberglass, cellulose and foam board products. These cost-effective hybrid systems use SPF to insulate and air seal, and use other insulations to provide assembly R-values that meet energy codes. In colder climates, special design considerations are needed to address potential moisture condensation issues.

Other Questions

  1. Does SPF emit odors?
    Some SPF materials may give off a noticeable odor for several days after application. These odors, noticed by some people, are usually caused by unreacted amine catalysts, and have been described as smelling like fish, cat urine or fresh latex paint. They are not indicative of a chemical hazard, but can be a general nuisance. Supplementary ventilation of the work area for a few days is recommended to reduce these odors. If other odors are present or persistent, or the foam is discolored or inherently sticky, or friable, these are symptoms of an improperly installed foam.
  2. Does SPF absorb water?
    Closed-cell foams, by nature, are resistant to water absorption, and are approved by FEMA as a flood-resistant material. Open-cell foams can absorb and retain liquid water at varying rates. It is important to consider the different properties for each foam type for each application.
  3. Can spray foam shrink?
    When improperly applied, some SPF, particularly closed-dell foams, products may shrink and pull away from structural members. Improper equipment settings or excessive pass thicknesses can result in foam shrinkage. While isolated amounts of shrinkage can occur, the number and size should not be extensive. Cracks and gaps caused by shrinkage can compromise the air sealing performance of the SPF, and could result in moisture condensation problems in colder climates. Extensive shrinkage should be repaired.
  4. What causes delamination and adhesive failures with SPF?
    Much like painted coatings, SPF should strongly adhere to nearly all construction materials that are clean, dry and free of oils and grease. If the substrates are free of oil, dust, dirt and moisture, and applied according to manufacturer’s instructions, there should be no problems with SPF adhesion. Adhesion should be occasionally checked by tearing a small area of foam from the substrate. When properly adhered, the foam itself should tear, leaving a thin but visible residue of foam on the substrate. However, SPF may not adhere well to some construction materials, such as polyethylene sheeting, under-cured concrete (containing excessive moisture or surface contaminants) and certain metals. These materials may need special surface treatments, such as primers or coatings, before SPF can be applied.
  5. What is SPF overspray?
    SPF applications, especially high-pressure foams, will leave a coating of fine droplets on all surfaces near the work area. Depending on the surface material, these fine droplets may not be easily removed. It is impossible to completely remove SPF overspray and residue from most porous surfaces. On smooth surfaces, SPF overspray may be mechanically removed using buffing and polishing compounds. SPF cannot be dissolved using most common solvents. All finished surfaces, and especially smooth surfaces such as glass, porcelain and metal, should be thoroughly masked prior to application.
  6. Is SPF susceptible to mold and mildew?
    All building materials, when installed to create a building envelope assembly, work interactively as system, to control the movement of heat, air and moisture. When not properly designed or installed, moisture can move through the building envelope and condense on cold surfaces that are below the dewpoint temperature or create high levels of moisture. This moisture, at certain temperatures, in the presence of organic food sources (paper, wood, bacterial dust, etc.) can provide the conditions necessary to promote the growth of mold and mildew. While SPF is not a source of food for mold, mildew and bacteria, organic dusts can collect on the surface of the foam. In combination with moisture at the right temperatures, these organic dusts can result in mold and mildew. SPF, 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.
  7. What is a chemical exotherm, and how can it cause damage?
    The chemical reaction used to create polyurethane and polyurethane foams give off heat, which is called an exothermic reaction. Closed-cell SPF products, when installed at pass thicknesses exceeding manufacturer’s recommendations, can generate excessive heat that can be trapped inside the foam. This heat can results in poorly formed foams that dramatically reduce coverage rates and diminish product performance, causing loss of R-value or shrinkage. In extreme cases, where closed-cell foam is applied at thicknesses several times the manufacturer’s limits, can generate enough heat to self-ignite the foam. The SPF contractor should always follow manufacturer’s installation instructions regarding pass thickness and times between passes to eliminate damage caused by exothermic reactions.