Window Fitters Guide to Window Installation 15 ©2022 AWDI, LLC Do not reproduce without permission While the term “Spray Foam” is often widely used in construction, there are two different types and each has its advantages and disadvantage. Spray foam has been shunned by window installers and manufacturers over the years because foams, in the past, have either continued to expand after trim has been applied deforming the more pliable vinyl window frames, or because they have been over used to fill the gaps left when old windows are removed and the underlying rough opening has been exposed. Make sure the foam you use has been tested to industry standards and is labeled conforming to standards as a low expansion, low pressure foam. Most standards applying to window installation do not delineate between open cell foam and closed cell foam, the more popular “minimal expansion” foams are most frequently used and they are mostly closed cell. More confusing yet, is when foams are recommended, the compressed foam tape alternatives are called out to be open cell. When it comes to Spray Foams, it helps to under- stand the differences.Open-cell spray foam (ocSPF) has a 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). 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. However, ocSPF, like fiberglass and cellulose insulations, is moisture-permeable, and may require the installa- tion of a vapor retarder in colder climates. Closed-cell spray foam (ccSPF) has a closed cell structure which yields rigid hard foam, with a density of 1.8-2.3 pound per cubic foot (pcf), and can provide structural enhancement in certain framed buildings. The smaller cells trap insulating gas from the curing, which has a lower thermal conductivity than still air, and increases the R-value to anywhere from R5.8 to R6.9 per inch. Like ocSPF, ccSPF is also air impermeable at certain thicknesses and can qualify as an air-barrier materi- al. The bigger benefit is that the closed-cell structure of ccSPF also makes it water-resistant, and is the only spray foam that can be used where contact with water is likely. At a thickness of 1.5 inches, no additional vapor retarder is required for most applications. Spray Foam Insulation Industry tested and labeled as a Low Pressure/Low Expansion; i.e., will not warp or deform windows & doors Quick Setting Formulation: can be cut or trimmed in less than 1 hour Cold Temperature Application: can be applied in temperatures as low as 14˚F Insulation Value of R5: makes it an efficient method for stopping air and moisture infiltration Remains Flexible Once Cured: will not crack or dry out • • • • • Desired Properties Note: Be careful, shims can present a problem as they extend through the cavity and can allow water and air infiltration. Foam Tape used outside like backer rod can seal the opening and conform to the contours while allowing drainage. SAMPLE MANUAL
View this content as a flipbook by clicking here.