b'Note: Be careful, shims canSpray Foam Insulation present a problem as theyextend through the cavityand can allow water and airinfiltration. Foam Tape usedWhile the term Spray Foam is often widely used in outside like backer rod construction, there are two different types and each can seal the opening andhas its advantages and disadvantage.conform to the contours whileallowing drainage.Spray foam has been shunned by window installersand manufacturers over the years because foams, inthe past, have either continued to expand after trimhas been applied deforming the more pliable vinylwindow frames, or because they have been over usedto fill the gaps left when old windows are removedand the underlying rough opening has been exposed.Make sure the foam you use has been tested toindustry standards and is labeled conforming tostandards as a low expansion, low pressure foam.Most standards applying to window installation donot delineate between open cell foam and closedgas from the curing, which has a lower thermal cell foam, the more popular minimal expansion conductivity than still air, and increases the R-valuefoams are most frequently used and they are mostly to anywhere from R5.8 to R6.9 per inch. closed cell. More confusing yet, is when foams arerecommended, the compressed foam tape alternatives Like ocSPF, ccSPF is also air impermeable at certainare called out to be open cell. thicknesses and can qualify as an air-barrier materi-When it comes to Spray Foams, it helps to under- al. The bigger benefit is that the closed-cell structurestand the differences.Open-cell spray foam (ocSPF) of ccSPF also makes it water-resistant, and is thehas a cell structure where the cells are filled with air. only spray foam that can be used where contact withThe open-cell structure renders soft, flexible foam, water is likely.with a density of about 0.5-0.8 pounds per cubic foot At a thickness of 1.5 inches, no additional vapor(pcf).retarder is required for most applications.The R-value per inch of open-cell foam typically Desired Propertiesranges from R3.6 to R4.5 per inch. Unlike fiberglassand cellulose, the fine cell structure of ocSPF makesIndustry tested and labeled as a Lowit air-impermeable at certain thicknesses. The air- Pressure/Low Expansion; i.e., will not impermeability of ocSPF qualifies it as an air-barrier warp or deform windows & doorsmaterial, dramatically reducing air leakage throughthe building envelope, significantly lowering theQuick Setting Formulation: can be cut orbuildings heating and cooling costs. However,trimmed in less than 1 hourocSPF, like fiberglass and cellulose insulations, Cold Temperature Application: can beis moisture-permeable, and may require the installa- applied in temperatures as low as 14Ftion of a vapor retarder in colder climates.Insulation Value of R5: makes it an efficientClosed-cell spray foam (ccSPF) has a closed cell method for stopping air and moisture structure which yields rigid hard foam, with ainfiltrationdensity of 1.8-2.3 pound per cubic foot (pcf), and Remains Flexible Once Cured: will not crackcan provide structural enhancement in certainframed buildings. The smaller cells trap insulating or dry outWindow Fitters Guide to Window Installation152020 AWDI, LLC Do not reproduce without permission'