Non-Traditional Structural Materials Are Gaining Favor Among Forward-Thinking BuildersConsider the Alternatives

Except for what he needs for interior walls, Don Ferrier doesn't buy framing lumber anymore. For the envelopes of the half-dozen custom homes he builds every year in the Fort Worth, Texas, area, he uses structural insulated panels (SIPs). And he's not the only one.

Conventional wood framing still dominates U.S. home building, commanding a nearly 80 percent share of above-grade walls, according to the NAHB Research Center. But SIPs, insulated concrete forms (ICFs), structural steel framing, and precast concrete panels have helped steadily reduce framing lumber's market share by more than 10 percent in the last decade.

For most alternative structural systems looking to eke out market share in the residential realm, getting builders to try something new is the biggest bugaboo to mainstream acceptance. Other hurdles to widespread market acceptance include building codes that lag behind technology and cutting-edge builders, a lack of skilled labor for these new systems, price premiums for materials and labor, and logistical and supply chain issues that take contractors out of their comfort zone of their local lumberyards.

Still, with the combined pressures of increasing energy costs (and consumer consciousness), ever-faster cycle times, skilled-labor shortages, concern about customer satisfaction rankings, and waning lumber quality, housing insiders predict an upward trend will continue.

Here is a run-through of the features, advantages, and disadvantages of two of these systems, ICFs and SIPs:

Insulated Concrete Forms
ICFs are molded from expanded or extruded polystyrene into lightweight, interlocking foam blocks that serve as permanent forms for poured concrete walls. The resulting walls combine the thermal mass and strength of concrete with the energy-saving benefits of integral insulation panels. Sophisticated systems feature metal inserts that act like rebar within the blocks and as vertical, standard on-center nailing strips on both faces of the insulated wall structure.

Of the alternative structural systems trying to enter the mainstream of housing construction, ICFs have made the most headway. The NAHB has tracked the industry's trajectory from a 0.7% market share of above-grade walls for single-family homes in 1997 to a 6.5% share in 2006—equaling more than 103,000 homes in that year alone.

There are now about 60 manufacturers distributing ICFs across the country; the International Building Code accepts ICFs among poured-in-place concrete systems, enabling their use nationwide.

ICFs' most recent popularity is fueled by current events, primarily the Gulf Coast hurricane seasons of 2004 and 2005, as well as nationwide energy price hikes and the green building trend. "We're talking about a system that resists fire and high winds, creates an energy-efficient home, mitigates noise, and is highly durable," says Jim Niehoff, residential promotion manager for the Portland Cement Association in Skokie, Ill.

ICFs also offer production benefits. "Builders love them because they're easier and faster to use [than removable forms] and there's one less sub (insulation) to hire," says Frank Chambers, regional vice president of The Contractor Yard, a dealer in Nashville, Tenn.

Minnesota custom builder John Vogstrom took to using ICFs eight years ago, specifically to reduce the potential for mold- and moisture-related issues. Since then, he's further leveraged the energy efficiency of the system to get the most out of geothermal heating, among other green building practices; he also enjoys the ability to create larger window openings than he could with lumber.