Fitting Foam into Weatherization Retrofits
August 24, 2011
As energy costs continue to fluctuate, homeowners are seeing the benefits of becoming more eco-savvy. One growing area of focus is weatherization. When you consider that up to 40 percent of a home’s energy loss can be attributed to air infiltration*-a combined with recent government incentives-it’s easy to see why.
This booming new market offers contractors an opportunity to expand business offerings and increase revenue streams by providing a service that homeowners are actively seeking out, in large part due to the increased awareness recently brought to home air sealing and weatherization through various government programs. In addition, the government recently extended the insulation tax incentive, meaning homeowners will receive a tax credit for a certain percentage of material costs, making this a prime time for weatherization contractors to build their businesses.
A Smart Approach to WeatherizationTraditional air sealing methods in existing construction such as caulking and weather stripping require extensive time to apply. An alternative to these applications that creates an effective barrier is using low pressure spray polyurethane foam. Using SPF is one of the easiest, most efficient ways to stop air infiltration in new and existing construction.
Low pressure SPF kits are available with no additional equipment necessary to install. Small two-component kits are easy to transport and fit into tight spaces like crawlspaces and attics where high pressure spray foam rigs would be cumbersome. Minimal training is necessary and the product can be applied with only one laborer, so incorporating low pressure SPF into a business model is a cost-effective approach to entering a growing market.
Sealing Critical AreasAir infiltration in existing homes is most prevalent in key areas such as attics, crawlspaces and rim joists. Sealing these critical areas with SPF can greatly improve comfort and reduce energy costs for homeowners. Closed cell spray polyurethane foam is the best option when air sealing because it can also act as a vapor retarder, assisting with other common problems in existing homes that can lead to moisture and mold.
Spray Polyurethane Foam Applications: AtticsVented attics can often be the best environment for employing air sealing methods with low pressure SPF because attics typically contain several spots of air and moisture penetration. These problem areas include top plates, junction boxes, can lights, pipe penetrations and drywall-to-wood connections. Quickly spot treating these problem areas with a product like Handi-Foam SPF will seal unwanted air through these penetrations. Look for additional products to assist with spot treatments such as can light covers to help prevent the risk of fire hazards.
A quick flash coat of SPF (approximately 1/2-inch thick) on the entire attic floor is an even more effective way to ensure the tightest seal for the entire attic. When used in conjunction with traditional insulation methods, such as blown-in cellulose or fiberglass, this small flash coat of SPF will stop air infiltration while the traditional insulation material will add R value to maintain the building codes. Accessory products such as baffles will help keep air flowing through the attic to help prevent moisture and ventilation issues. Sealing baffle bases with SPF will assist in overall air sealing while maintaining the necessary ventilation.
Fomo Products recently completed a retrofit project on a home in northeastern Ohio. Prior to starting the project, Fomo conducted a blower door test-an EPA Energy Star recognized diagnostic method for measuring air exchanges. This testing was performed by a certified third-party Building Performance Institute accredited Building Performance Analyst. A critical seal was performed by applying SPF to the thermal bypasses. Critical seal points included top plates, pipe penetrations, drywall-to-wood connections, junction boxes, can lights, soffits and baffles. In addition, a 1-inch coat of SPF was applied over the entire attic floor to create an airtight critical seal and to stop air infiltration. This provided an R value of 6.2. The blower door test conducted after the attic seal was complete showed that air exchanges per hour dropped significantly, by 25 percent, before the cellulose was reinstalled.
Rim JoistsRim joists are another prime spot for air and moisture infiltration. Traditionally rim joists have been insulated solely with fiberglass, which does not stop moisture infiltration and could lead to mold problems when exposed to the elements. Additionally, since fiberglass is a thermal barrier and not an air barrier, it can’t stop air infiltration-the best defense against energy loss.
Creating an air barrier becomes vitally important in a rim joist because this is the primary area where cold, moist air infiltrates a house, potentially contributing to moisture related problems like molding and rotting. Sealing around the gaps in the rim joist (and then re-covering with the existing fiberglass) will also help prevent moisture from reaching the fiberglass to help prevent mold issues.
Sealing the rim joist with SPF can be done in three easy steps. First, remove any existing fiberglass. Then spray a flash coat of spray (approximately 1/2- to 3-inches thick) in the rim joist to create an airtight seal. Then the fiberglass can be placed over the SPF to further insulate and reach designated R values.
Recent case studies show a 10 to 20 percent reduction in air exchanges simply by sealing a home’s rim joists. For example, Fomo Products recently worked to seal rim joists on a 2,400-square-foot home in Kansas, built in 2007. By simply applying SPF to the rim joists, a reduction in the annual infiltration rate estimated at 11.4 percent was achieved. This reduction in air infiltration translated to an estimated cost savings of 19.3 percent in heating and cooling expenses, according to Hathmore Technologies, the certified HERS energy rater that performed the testing.
CrawlspacesCrawlspaces can be a major contributor of moisture in a home, as well as cause “cold spots” in the first main floor. Ideally, a crawlspace should be kept dry and tightly sealed and SPF is one of the easiest ways to insulate hard-to-reach areas like crawlspaces.
One common approach to sealing vented crawlspaces involves completely sealing the underside of the first floor (including the joists) with SPF and then covering it with an ignition barrier. Another method for creating unvented crawlspaces, involves covering the walls and floor with a vapor barrier and then applying SPF to seal and insulate from the rim joist down the walls and then following this up with an ignition barrier.
Homes have reached up to 30 percent savings on their annual energy bill after utilizing just one of these applications, which is a significant benefit to the homeowner.
It is important to note that it is necessary to wear air purifying or supplied air respirators during crawlspace applications due to a lack of proper ventilation.
A Winning CombinationSealing any of these single critical areas can help homeowners realize significant energy savings but an even greater reduction in energy can be reached by combining these seals. For example, by combining a critical seal in the attic with two inches of SPF applied to the rim joists in the basement, a 2,600-square-foot home built in 1983 achieved a 19.5 percent reduction in hourly air exchanges.
In addition to critical seal areas, SPF can be used to seal around gaps, cracks and pipe and wire penetrations to create an air barrier and increase energy efficiency. Visit www.fomo.com to see a weatherization video and view these applications in action.
Help for ContractorsVarious companies are offering weatherization contractors turnkey assistance programs and product resources to take their home performance contracting businesses to the next level. Comfort RX, for example, offers an assistance program that includes premium air seal products, marketing, application and product training, a full-circle marketing co-op program and comprehensive technical support for contractors, all without the costs of a franchise. For more information, visit www.comfortrx.com.
Working SmartFor every job using two-component spray polyurethane foam, the Center for the Polyurethanes Industry (www.spraypolyurethane.org) recommends several safety standards. Contractors should wear glasses or goggles, nitrile gloves, cover all exposed skin and use a NIOSH-approved respirator.
*Source: The Department of Energy