A centerpiece of the Professional Builder Show Village at the International Builders Show (IBS) in Las Vegas, Nevada, was Nationwide Homes' Osprey Eco-Cottage-a tiny, 513-square-foot example of what you can do with a little creative innovation-and COMFORT FOAM® spray-applied polyurethane foam (SPF) insulation and air barrier in the roof, walls and floor system.
The Osprey is actually the largest of the Eco-Cottage models, sporting a full bedroom and bath, as well as a great room with galley-style kitchen. Smaller model Eco-Cottages are a mere 250-square-feet of combined living space. The intent of the Eco-Cottages is to provide an economical, sustainable solution to vacation retreats, guest houses, home offices or other small-scale housing needs. Delivered to the site more than 90 percent complete, the IBS Osprey Eco-Cottage was installed in about one day.
Though spray foam insulation is a standard, factory-applied system for Nationwide Homes and their parent company, Palm Harbor Homes, this application is unique. In most modular construction, roof systems are hinged and shipped separately from the other modules. This makes utilizing a continuous application of SPF difficult. Because the Osprey Eco-Cottage has such a low profile, it was shipped on one truck (instead of separate modules on separate trucks) and COMFORT FOAM insulation was used for the entire building envelope, providing optimal thermal, moisture, and structural benefits.
Stephanie Thomas, research architect with Florida Solar Energy Center (FSEC), is part of the team that has worked with Nationwide and Palm Harbor Homes for many years through their Industrialized Housing Partnership - a U.S. Department of Energy (DOE) Building America team that researches better ways to build high-performance homes. According to Stephanie, who worked with Nationwide on the 2010 IBS show home, COMFORT FOAM closed-cell SPF insulation was used in conjunction with batt insulation in the floors, walls and ceilings because it offers higher R-value using less material and better air sealing performance.
Though building modular homes in a factory provides great benefits, it also provides challenges. Modules must be shipped significant distances-sometimes up to 200 miles-and driving parts of a home down the highway isn't very forgiving.
Mike Draper, Florida division vice president for Palm Harbor Homes sums it up best when he says, "In the past, it was inevitable that we'd get interior drywall cracks in our product during transport. When we started using BASF spray foam on the studs and the back of the drywall surface, it significantly lessened the amount of drywall cracking as our homes went down the road at 65 miles per hour. That saves us money on the back end because we don't have to make repairs-the product simply holds together better."
In addition to the structural benefits, Draper notes that Palm Harbor Homes builds each of their homes to ENERGY STAR® standards, as well as the National Association of Homebuilders (NAHB) Green Building Standard. "Using fiberglass we'd get gaps or compression and when FSEC would test the home to make sure the thermal barrier was in place, we'd always find problems. With spray foam, no more problems," says Draper.
In addition to meeting ENERGY STAR and NAHB Green, Nationwide Homes went one step further with the Osprey Eco-Cottage at IBS and participated in the DOE's Builders Challenge, an initiative focused on rewarding builders who go "a step beyond" in meeting high-performance building targets. The Osprey achieved a 68 on the DOE's EnergySmart Home Scale (E-Scale), making it about 32 percent more energy efficient compared to a typical new home.
In addition to these significant achievements and the use of COMFORT FOAM, green features in the Osprey Eco-Cottage include:
- ENERGY STAR, low E windows (U=0.29, SHGC=0.19)
- R-21 walls, R-19 floors, R-50 ceilings
- 15.5 SEER /8.5 HSPF variable frequency drive, ductless HVAC
- ENERGY STAR appliances
- Tankless water heater
- Extensive use of controlled compact fluorescent and LED lighting
- Volatile organic compound (VOC) source control including zero VOC paint
- Outside air ventilation
- Air filtration and cleaning system
- Central vacuum system
- Low flow faucets and showerheads with supply runs no more than 20 feet
- Termite- and weather-resistant siding
- Resource efficient modular construction and construction waste management
- PV- and solar-hot-water- "ready"
- Scalability or 'growability' (modules can be added for growing family)