Spray Polyurethane Foam

  • What R-Value do I need for my specific project?
  • What are the properties of Spray Polyurethane Foam Insulation (SPFI)?
  • Where in the envelope is Spray Polyurethane Foam used?
  • Who applies SPF?
  • What are the advantages to using Spray Polyurethane Foam Insulation?
  • What properties does an air barrier assembly require and does spray polyurethane foam provide them?
  • Is SPF recognized in the National Building Code?
  • Does spray polyurethane foam “off-gas”?
  • Does spray polyurethane foam burn?
  • Can SPF be used with Other Insulations (Hybrid Insulation Systems)?
  • Can SPF be used as an air barrier?
  • What is the difference between low-pressure and high-pressure SPF application?
  • How soon can buildings be re-occupied after SPF installation?
  • Should access to the work area be restricted during and immediately after spray foam installation?
  • What are the differences between open-cell vs. closed-cell SPF insulation?
  • Does SPF absorb water?
  • Does SPF emit volatile organic compounds after installation?
  • What fire protection measures (thermal or ignition barriers) are required for SPF?
  • What are the structural benefits of closed-cell SPF?
  • Is SPF suitable for residential retrofit insulation applications?

In British Columbia, the recommended R-Values are as follows:

Attic Roof – Any uninsulated attic/roof assembly = R-40 (Approx 6.5″ of closed cell foam)

Wall – Any uninsulated exterior wall cavity = R-20 (Approx 3.5″ of closed cell foam)

Floor – Over unheated, uninsulated space = R-28 (Approx 4.5″ of closed cell foam)

Basement Wall – Below grade concrete = R-20 (Approx 3.5″ of closed cell foam)

R-Value Source

  • Continuous, seamless, no joints
  • Can fill cracks, voids and holes
  • Adheres to wood, metal, concrete, masonry, almost all plastics
  • Almost totally impermeable to air
  • High insulation value
  • Durability and long service life
  • Can be sprayed overhead, doesn’t sag
  • Speedy, quick set, installation
  • Doesn’t settle
  • Only thermal insulation which is tested for VOC’s
  • Can be used as a water barrier
  • Foundations
  • Crawl spaces
  • Walls
  • Header spaces
  • Roofs
  • Ceilings
  • Interior walls
  • Can be used as the primary air barrier material
  • Can be used to connect other building materials together

Only trained, certified and licensed installers can install medium density spray polyurethane foam insulation into buildings, ensuring professional and consistent installations. The Canadian Urethane Foam Contractors Association Inc. uses the SPF Quality Assurance Program to train, certify and license the installers.

The installer must work for a Licensed Contractor who is responsible to ensure all the requirements of the CAN/ULC S705.2 Installation Standard is met and that all safety and building code requires are adhered to.

  • It acts as a seamless insulation making it more efficient than any other material used in the industry
  • SPF is airtight which eliminates all air infiltration or exfiltration
  • It is durable and odourless
  • It will not settle or shrink, making it stable
  • Because SPF is light and versatile and has strong adhesive properties, it easily fills difficult to reach places and adheres to most clean surfaces
  • It is quick and easy to install, making SPF an inexpensive alternative to other types of insulation.
  • It reduces heating and cooling costs by maintaining a more controlled indoor air evnironment.
  • By providing a controlled environment, air quality within the home can be cleaner and without external contaminants (dust, allergens, pollutants etc).

All medium density spray polyurethane foam is an air barrier material at the minimum installed thickness allowed of 12mm. An air barrier assembly must meet all the requirements outlined in the local Building Code. To do so, other materials must be used to “transition” to penetrations and to terminate. Normally a sheet membrane is installed at these transition points then sprayed over. With a declared and tested assembly, spray polyurethane foam provides all the requirements for an air barrier as required by Building Codes.

SPFI is not only recognized as a thermal insulation, with the National Standards being referenced right in the Building Code but also SPF meets the requirements for a air barrier material and a air barrier system. SPF, in some cases can provide the Code required vapour barrier. SPF can provide thermal insulation, air barrier system, vapour barrier and drainage plane all in one application when used in cavity wall construction. SPF has one of the highest R-Values per inch of any insulating material available.

All manufactured materials will off-gas to some extent. Some building products will off-gas in large qualities

Medium density spray polyurethane foam meeting the CAN/ULC S705.1 Material Standard is the only building product that is tested for occupant conditions. The industry has then taken an unprecedented stance and required that all manufacturers meet a maximum limit of 1/100 of the government allowable limit. Manufacturers have met this requirement in less than 24 hours.

Spray polyurethane foam is an organic material and all organic materials burn. Medium density spray polyurethane foam contains a fire retardant so that the flame spread is less than 500 when tested in accordance with CAN/ULC S102 and specimens prepared in accordance with the requirements of the National Building Code.

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.

Spray foam, when applied to certain minimum thickness (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.

Low pressure SPF applications fall into two categories, sealant foam and insulation foam:

  1. Low Pressure Sealant foam consists of one-component aerosol cans and two-component spray foam kits.One-component SPF aerosol cans typically hold from 0.5 to 2 lb. of SPF and are used for sealing cracks, crevices and small holes.  They are available at retailstores and are popular for do-it-yourself (DIY) projects.Low pressure two-component kits consist of small A- and B-side pressurized cylindersconnected to plastic hoses and a disposable spray nozzle or gun. They are most commonly used by SPF contractors  for air sealing,patching and repairing of small areas of spray foam (up to 100 bd. ft).  The two-component kits can range from 5 to 30 lb. of material.
  2. Low Pressure Insulation SPF systems consist of refillable cylindersof A- and B- components in sizes ranging from 50 to 100 lb. of material. The cylindersare typically pressurized to around 200 to 250 psi with a pumping capacity between 10-15 lb. per minute with a maximum hose length of up to 200 feet. Most systems are unheated and use equipment specific to the SPF system.

High Pressure SPF systems consist of A-and B components being transferred from unpressurized 55 gallon drums or larger tanks and pumped through a proportioner that heats and pressurizes the materials. The materials reach pressures ranging from 800 to 1500 psi and temperatures of 100-140°F as they pass through heated hoses and are mixed at the spray gun. Pumping capacity varies considerably depending on the size of the proportioner and can range from 10 lb. per minute to more than 45 lb. per minute throughhose lengths up to 350 ft.

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. Your contractor and their supplier can recommend re-occupancy times based on job specific conditions.

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.

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.

Open-cell spray foam (ocSPF) has an open cell structure where the cells are filled with air. The open-cell structure renders soft, flexible foam, with a density of about 0.5-0.8 pounds per cubic foot (pcf). Still air is the primary insulation medium in ocSPF, 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 ocSPF makes it air-impermeable at certain thicknesses. The air-impermeability of ocSPF qualifies it as an air-barrier material, dramatically reducing air leakage through the building envelope, significantly lowering the building’s heating and cooling costs. ocSPF, like fiberglass and cellulose insulations, is moisture-permeable, and may require the installation of a vapor retarder in colder climates. .

Closed-cell spray foam (ccSPF) has a closed cell structure which yields a rigid, hard foam, with a density of 1.8-2.3 pound per cubic foot (pcf), and has been demonstrated to provide 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, making it a great choice in applications where clearance is limited. Like ocSPF, ccSPF is also air impermeable at certain thicknesses and and can qualify as an air-barrier material. The closed-cell structure of ccSPF 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 exterior side of the building envelope). At a thickness of 1.5 inches, ccSPF has a moisture permeance typically less than1.0 perms and no additional vapor retarder is required for most applications.

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.

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.).

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.

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.

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.

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