Here’s A Look At How Using SIPs Can Attain High-Energy Efficiency And Improve Home Construction
By Scott Bergford, Owner, Scott Homes, Inc. July 6, 2009
Building with SIPs has resulted in a 60 percent reduction in costs to heat our homes. Customers love the lower utility bills. In light of rising energy costs and growing environmental awareness, more homebuyers are focusing on the energy efficiency of their new home’s design and construction. It’s a home attribute that’s gone from a “nice to have” to being a deciding factor for many people.
Achieving dramatic improvements in home energy efficiency requires advanced building techniques and products, not simply doing existing things better. Think of it like a horse versus a car: no matter how well you feed and train the horse, it will never run as fast as a car.
To improve energy performance, meet other green building goals, and streamline the building process, my company has been usingstructural insulated panels (SIPs) for the past 12 years.
In conjunction with double-pane, low-e, energy spacer glazing and hydronic radiant floor heating systems, building with SIPs has resulted in a 60 percent reduction in costs to heat our homes. For many of our SIP homes, it costs only $200-$300 per year to heat them. These numbers are significantly lower than what the costs are to heat the average home in Western Washington State where we build.
If you’ve been thinking about trying SIPs, it’s not hard to get started and there are numerous benefits. As a builder, we love SIPS because they enable us to dry in a house much faster, the walls are stronger than stick built, they always are straight and plumb, we have significant reduction in call-backs, we’re able to easily qualify for EnergyStar and Built Green® certification requirements, it’s easier to market and sell our homes because of the significant energy efficiency and improved indoor air quality, and we have extremely happy customers.
My customers tell us they love their SIP-built homes because they feel more comfortable and that the home gives them peace of mind due to its solid, quality construction, durability, and the healthy clean air environment. And, they LOVE the lower utility bills!
Structural Insulated Panels consist of two outer skins of oriented strand board and ann inner core of expanded polystyrene that are laminated together.
Energy Savings
SIPs are prefabricated structural and insulated components used to build walls, ceilings and floors. They consist of two outer skins of oriented strand board (OSB) and an inner core of expanded polystyrene laminated together to form a monolithic building panel with extreme energy efficiency.
They replace conventional stud or stick frame construction and need no additional insulation or skeleton for support. Because SIPs houses have fewer joints, it’s easier and cheaper to create a tight building envelope than when building with stick framing and fiberglass batts or spray-in insulation.
The U.S. Dept. of Energy’s Oak Ridge National Laboratory has conducted many tests on building with SIPS. One important evaluation is comparing blower door tests of SIPs homes versus stick-framing. They found that SIPs reduce air leakage by about 90 percent, while also providing a higher overall R value for the completed wall. The benefits are so consistent that EnergyStar removed the requirement for a blower door test on a gas heat system in order to certify a SIP built house. Another test demonstrated that the whole house insulation value of a SIP wall is much greater than a stick built wall. You can see the results on the Structural Insulated Panel
Association’s Web site.
Washington State University ran independent tests on three of our SIP homes and estimated the energy consumption to be 60 percent less per year than for a typical 2,250 square-foot house.
Another financial benefit to consider beyond the ongoing energy savings is the availability of federal, state and local tax credits and deductions for energy efficient building practices, such as SIPs. All our homes in the last two years have qualified for the $2,000 Federal energy tax credit!
Additional Green Benefits
In addition to superior energy efficiency, SIPs construction supports environmentally responsible building in several other ways, including indoor air quality, waste reduction, and recyclability.
Indoor air quality. Next to energy efficiency, indoor environmental health and air quality are typically top of mind with homeowners when it comes to building green. By creating a tight building envelope, SIPs help stop pollen, mold, dust and other irritants and pollutants from seeping in. Some manufacturers’ SIPs also do not contain formaldehyde or other off-gassing components that can negatively impact indoor air.
Waste reduction
We’re all familiar with the large dumpsters required to hold framing material waste at the typical job site. In many ways, it’s become an expected cost of doing business and is typically seen as just the way things are. However, using SIPs eliminates large volumes of wood waste – up to two thirds. The SIPs manufacturer cuts all of the pieces in their factory, eliminating much of the need for builders to cut lumber to length on site. This not only helps the environment, but also reduces labor costs and disposal fees.
Recyclability
Many SIPs are completely recyclable, including both the OSB, as well as the insulating foam core. Depending on the product, the foam core itself may include recycled content. Check with the manufacturer to see what amount they may be using.
Bottom Line Advantages
While building green is important, we also use SIPs because they help speed construction and create happy homeowners – both critical for profitability and long-term success.
Fast Construction
SIPs install much faster than stick framing. Because the structural elements and insulation come in an integrated piece, there’s no need for separate framing, insulating and sheathing work. Plus, the electrical chases are pre-cut so there’s no need to drill through studs for wiring. The window and door openings are also pre-cut, including curved doors and other complex features. As a result, we can dry-in a home within a matter of days, instead of weeks.
Quality finishes
The large, one-piece panels arrive at the job site straight and square, and are easy to install plumb. They eliminate the waviness that can be difficult to avoid in stud walls. Their straightness not only creates a better-looking wall, but also provides even anchor points for cabinets and smoother operating windows and doors. SIPs are fairly straightforward to place and attach to the foundation or to other framing members.
Getting Started
Although most builders have not used SIPs, they are pretty easy to get used to. The primary requirement is a willingness to try something new. For an experienced framing crew, learning to work with SIPs typically only takes a few hours. SIPs suppliers and distributors typically provide detailed assistance, from design through construction. For example, ourSIPs manufacturer, Premier Building Systems, works closely with us on design, integrating SIPs from the beginning. In other cases, they can readily convert a stick-framed design to one with SIPs. They then make the panels and deliver them to our job site ready to install.
The panels are fairly straightforward to place and attach to the foundation or to other framing members. Once installed, it’s critical to seal all joints between panels and other framing components with mastics, tape or other sealants to provide a tight envelope. The manufacturer will provide details on which methods and products are required with their SIPs.
As far as other aspects of construction, working with SIPs is similar to conventional framing. Because they are wood sheathed, they are easy to fasten finishing materials to with screws or nails.
Conclusion
Once we started using SIPs, we decided to never go back to stick framing. My customers say they can immediately see and feel the difference in our structural insulated panel built homes. With the benefits to customers, builders, and the environment, we believe that most homes will eventually be built with SIPs.
About the Author : Scott Bergford is the owner of Scott Homes, a custom builder in Olympia, Washington, committed to green homebuilding and state-of-the-art construction practices. His company was honored as the 2009 “Builder of the Year” in the EnergyValue Housing Awards hosted by the NAHB Research Center and U.S. Department of Energy (DOE).
