One. Wall Cavities
While spray foam insulation is an exceptional option for insulating the walls of a home, high-pressure SPF is not cost effective for just insulating a basement or a room addition. However, that doesn’t mean these areas are relegated to porous fiberglass batt or blown cellulose insulation. On the contrary, homeowners can get the best of both worlds by air-sealing and insulating their walls with both SPF and fiberglass.
Commonly called a flash and batt application, this two-part system involves an initial quick, or “flash”, installation of roughly two inches of spray foam to a wall cavity. When the foam has cured, fiberglass batt insulation is installed to fill the rest of the cavity. The spray foam functions primarily to seal and insulate the wall cavity, which is further insulated by the fiberglass batt. Because the application is inherently small, it’s perfect for low-pressure spray foam systems, such as Touch ‘n Seal’s Constant Pressure Dispensing System (CPDS). Also, because spray foam isn’t filling the entire wall cavity, the application is more cost effective per board foot for homeowners.
Crawlspace conditions are such that it’s highly inadvisable to use fiberglass batt insulation, as it readily retains moisture and allows the passage of air. Spray foam insulation is a comprehensive solution to counteract these issues, as Joel Few of Carolina Aire & Mold Solutions points out:
“The seamless protection of spray foam insulation not only significantly lowers energy costs, it also eliminates moisture, mold, and mildew, and keeps out insects and pests,” Few said. “All of these benefits add value to a home and increase the occupants’ comfort level.”
However, as with basements and room additions, crawlspaces are usually too small for high-pressure foam insulation to be a cost-effective solution. Basically, the only financially feasible solution for sealing and insulating to create an encapsulated crawlspace is the utilization of low-pressure foam kits and systems like the CPDS.
Three. Rim Joists
Rim joists, or band joists, which are above grade, are something of a nexus for energy efficiency, comfort, and health within a home. For older houses, rim joists are typically neither insulated nor sealed, which contributes to air leakage and outside air infiltration (including moisture and airborne particulates). Much like crawlspaces, rim joists shouldn’t be insulated with just fiberglass batt insulation, as it will do nothing to prevent the passage of air and humidity between the outdoors and the inside of a home. Furthermore, no rim joist is big enough to warrant the use of high-pressure foam, so once again, low-pressure foam is the only cost-effective sealing and insulating solution. Ideally, rim joist cavities should be filled with low-pressure spray foam, as they’re small enough not to be cost-prohibitive for cavity-fill applications. However, it’s not uncommon to see the flash-and-batt system used for rim joists when necessary. In any case, rim joists can be effectively and efficiently sealed and insulated with low-pressure kits like Touch ‘n Seal’s Two Component Foam Insulation Kits.
Four. Knee Walls
Despite their size, knee walls can be significant contributors to heat loss during the winter, sweltering attics in the summer, and general air leakage and infiltration. These short walls, which stand upright beneath sloped ceilings, are often insulated with fiberglass batts. However, the backsides of knee walls are commonly left without sheathing, so the fiberglass insulation can eventually fall on the floor in the space behind them, leaving the knee walls bare. Of course, even with sheathing, knee walls can suffer from air leakage and infiltration. Therefore, it’s best to install sealed and insulated knee walls, which can be accomplished with applications of spray foam alone, or flash-and-batt applications. Due to their small surface area, low-pressure spray foam is ideal for tackling knee wall applications, and Touch ‘n Seal’s Two Component Foam Insulation Kits provide the most cost-effective way to install them.
Five. Ducts & Penetrations
People often hear about the major contributors to air leakage and infiltration, like rim joists, but as the saying goes, it’s the fine details that matter. In this case, the fine details are all of the penetrations from HVAC systems where air can pass freely. Not only can duct vent penetrations contribute to air leakage, but also the ducts themselves can leak, as they’re assembled in sections that are simply joined together by sheet metal screws. Ducts that leak conditioned air can increase the loads on A/C units, and therefore increase energy bills, so sealing ducts and vents is an important energy efficiency initiative. Low-pressure foam systems like Touch ‘n Seal’s Two Component Foam Insulation Kits can be used to seal both vent penetrations and duct seams. For smaller penetration applications, one-component low-pressure foam cans, like Touch n’ Seal’s One Component Foam Sealants, can be used to quickly and efficiently prevent air leakage.
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