Builders using SIPs
A study conducted by the RS Means unit of Reed Construction Data shows that residential builders can reduce their framing labor needs by as much as 55 percent by using structural insulated panels (SIPs) instead of conventional “stick-building” methods.
The study was conducted on a two-story, three bedroom, Cape style home in Tilton, New Hampshire. Engineers from RS Means observed the construction of the home and compared the workers’ productivity with a benchmark home built using 2×6 construction and fiberglass batt insulation.
The SIP installation crew spent 130 fewer hours framing the exterior walls and roof of the home by eliminating many time-consuming steps from the construction process.
Used for walls, roofs, floors, and foundations, a structural insulated panel sandwiches a rigid foam insulating core between two structural skins usually made of wood. The seamless, closed-cell rigid foam core reduces air leakage and thermal bridging through the panels by providing a continuous span of insulation. In a large, single component, SIPs perform structural, insulating, and air sealing functions, and install quickly saving builders time and money.
The Tilton home used energy-efficient SIPs for all exterior walls, the roof, and two window dormers. Complex and hard to insulate dormers are easily pre-assembled using SIPs and hoisted into place with a crane. Installation of the SIPs dormers was found to be 25 percent faster than the benchmark home.
By using precut channels, or “chases” in the foam core of the panels, electricians were able to wire the Tilton home with 11 percent fewer hours than its 2×6-framed counterpart, according to the study.
Building with SIPs also reduces waste since they arrive at the jobsite prefabricated and require less measuring, cutting and framing. The study noted a 93 percent material utilization rate that sharply reduces the cost of jobsite debris disposal.
SIPs create a well-insulated and airtight building envelope, and SIP-built homes repeatedly demonstrate annual energy savings of 50-60 percent when combined with other energy saving techniques. For example, SIP test homes monitored by the Department of Energy’s Oak Ridge National Laboratory (ORNL) show heating and cooling costs as low as 32 cents per day. Airtight construction also provides better indoor air quality for occupants.
Due to the airtight qualities of SIP construction, the EPA waived its blower door test requirements for any SIP homes qualifying for the Energy Star program, thereby reducing the cost of an Energy Star home inspection. Coupled with federal and state tax incentives available for energy-efficient home construction, SIPs offer builders another money saving option.