Many builders these days are on a quest to find products that are easier to use, are environmentally correct, and offer the homeowner energy efficiency savings with a higher quality of construction. It takes a few "maverick" builders to try a new product, become successful with it, and the rest seem to follow suit in short order. Such is the case with SIPs. Referred to as the "Pentium Chip of the construction industry", Structural Insulated Panels, now used for both structural walls and roofing on new homes, are some the fastest growing engineered wood products on the market.

Jim Tracy, Executive Director of the SIP Association, says SIPs save labor for the contractor, provide a more comfortable and durable structure to the homeowner, and are vastly more energy efficient than the old fashioned stick-framed house. Installation can take place in a fraction of the time as well, since the panels are cut and nailed in a factory, where weather and equipment restraints are not a factor.

The three elements of SIPS; the foam core with its inner and outer sheathing and lamination, perform astonishingly well in strength and seismic capacities. Surprisingly enough, this was determined way back in the 1930's, when the U.S. Products Research Laboratory built some of the first SIP houses in the Los Angeles area.

The rigid foam core that is present in all SIP products is significantly more efficient than all other forms of insulation. Why? "Because air is unable to move through it," says Tracy. "The result is a more comfortable and quieter indoor environment. The panels also offer a flat, solid surface for attaching finish materials, such as drywall, siding, and cabinets," adds Tracy. And, because SIPs don't contain many studs (common 2 by 4's), SIP construction produces no twisting and warping of lumber.

The environmentally "green" crowd should be pleased as well, since SIPs use up to 65% less raw timber than other construction techniques. This, in itself, is a huge benefit to the environment. The wood used in SIPs is typically farmed or weed wood, taken from rapidly growing second growth (not old growth) trees, which are harvested for the sheathing or " skins" for SIPs.

SIPs are assembled with a varied array of combinations of joining mechanisms, called "splines." These splines can be old lumber, engineered lumber products like I-Joists, strips of OSB called surface splines or even cam locks, which work like little deadbolt locks pinning one panel to the next. The various properties of these different splines can determine and alter the panel's stiffness. This type of engineering allows the panels to be used at different spans or under different loads. SIPs have been used successfully in virtually every conceivable climate and load condition in the world, according to Tracy.

SIPs are fully compatible with any floor or foundation system. Once the floor is finished, the walls are ready to be tipped into place. Boom trucks, cranes, or good old-fashioned muscle can put them into place, and there are no special tools to buy or skills to learn for carpenters, since all the pieces are pre-cut.

The crowning glory of a SIP house, however is the SIP roofing, which is literally "flown" into place by a boom truck. SIPs produce true vaulted, or cathedral ceilings, and, because of the rigid insulation used in SIPs, this cost-effective space can be used as a second story or loft, since they are considered one of the most energy efficient ways to construct a home.

When a house is "dried in" (closed in from the weather) the process of finishing the panels with wiring and plumbing begins. Wiring is a breeze, with wire "raceways" pre-built into the panels, at predetermined heights for both switches and outlets, creating a network of conduits or access runs for the electrician. Although exterior walls usually don't contain water lines, plumbing vents can go through SIP walls with a small amount of preparation by the manufacturer or builder, depending on local building code requirements.

After these trades have had their day, panels may be finished with drywall or plaster inside, and any exterior surface, such as brick, stucco, siding, or stone. "The real savings come into play at this point," says Tracy. "With each passing day, about half the energy of the traditionally stick-built home is saved in a SIP-constructed dwelling, for both heating and cooling."

To be sure SIPs are manufactured under the most stringent of standards, each SIPA Manufacturing member is required to maintain an independent third party quality assurance program in their plant or factory, according to Tracy. All things considered, SIPs generally cost about the same as lesser building materials, with the efficiencies of any system becoming more evident with time. No job site waste contributes to the savings in landfill fees. Combine this with labor savings, faster drying time, and better drywall utilization, and you have an idea that SIPs may indeed be the future of homebuilding. An interesting note here: for the homeowner, even a 4-inch SIP wall has been proven to surpass a 6-inch frame wall in thermal efficiency, according to the Structural Insulated Panel Association.

In hurricane country, where Insulated Concrete Forms are increasingly being used to create "safe" housing, SIPs may be used in combination, to create an incredibly energy efficient, structurally sound home

For more information on SIPs, visit their website at www.sips.org. Links are provided there to a SIPs manufacturer in your area.

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Published: December 17, 1999

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A veteran of the real estate and homebuilding industries since 1986, Dena Kouremetis first joined Realty Times as a new homes writer in 1998. Since then, she has authored four books, written consumer columns on new homes issues for websites and newspapers all across the country, contributed to builder trade magazines, appeared as a guest expert on several radio shows and even created a ten-chapter podcast for LendingTree.com’s homebuilder website, iNest.com, now available on iTunes, entitled Uncharted Waters; Navigating the Purchase of a New Production Home. Kouremetis recently joined her local Folsom, CA Coldwell Banker office as a broker associate while continuing to write for the real estate industry. For the past three years, she has been training real estate agents for both the resale and new homes industries, putting her experience, research expertise and gift of expression to work to help others entering the business.