Green Guide

ARCHITECT BILL CHALEFF & STRUCTURAL INSULATED PANEL (SIP) CONSTRUCTION
STORY BY EMILY ANDREN

“Green is here now,” says Bill Chaleff, A.I.A., LEED Accredited Professional and co-founder of the architectural firm Chaleff & Rogers in Water Mill speaking to Networking® magazine. "Compelling economic incentives and consumer voter power are changing legislative priorities."

“If you’re going to build, legislation will require you to build greener. Three Long Island townships have adopted Energy Star standards for all new construction, and five others have it on the agenda. Suffolk County requires all county buildings costing $1 million or more to comply with LEED standards,” he says.

ENERGY STAR is a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy helping us all save money and protect the environment through energy efficient products and practices. LEED stands for the Leadership in Energy and Environmental Design (LEED) Green Building Rating System, a nationally accepted benchmark for the design, construction and operation of high performance green buildings. (See page 27 of Networking® magazine’s August 2007 issue.)

Chaleff is a longtime believer in green buildings and the author of many articles on the subject. “I never thought I’d live to see this happen,” he says. “For years I’ve been an outsider banging my head against the wall. Now, the building community is struggling to pump out green products to keep up with the demand.”

Since 1974, Chaleff has designed over 200 energy-efficient buildings in Long Island, including his first Structural Insulated Panel (SIP) design 20 years ago. In 2007, he received the Clean Energy & Green Building award from Vision Long Island, which promotes quality growth and preservation on Long Island.

To build a well-insulated house with minimal air infiltration Chaleff chooses SIPs, defined as sandwiched panels of Oriented Strand Board (OSB) with Expanded PolyStyrene (EPS) foam. In cross-section, a SIP resembles an ice cream sandwich: a thick inner core of Styrofoam between thin layers of Oriented Strand Board (OSB), equal in strength to plywood and half the cost.

The Expanded PolyStyrene (EPS) core looks like the Styrofoam in coffee cups. The raw material, which has the look and feel of talcum powder, is actually microscopic beads. Subjected to steam, oxygen and heat in a blow-mold press, the beads expand to 1/8 inch in diameter. The resulting EPS, 97% air and 3% Polystyrene, has excellent insulation properties with a better R-value – resistance to heat flow – than fiberglass.

A SIP building has no framing; its outer walls and roofs are assembled from the insulated panels and joined together by long metal screws and sealant in a “stressed skin structure.” For people used to wooden frame construction, this concept can be elusive. “It’s like comparing a human’s internal skeleton to a lobster’s exoskeleton,” Chaleff explains. A refrigerator is a familiar example of stressed skin structure, with sturdy exterior walls composed of metal and plastic skins enclosing a foam core.

SIP buildings use at least 50% less energy than equivalent frame construction because insulation resists the flow of heat better than the wooden beams, according to Chaleff. "In a frame house, wooden beams represent about 15% of the surface area compared to 2% wood in SIP construction," he explains. Lowered energy usage with SIPs dramatically reduces the size and costs of the necessary heating, ventilation and cooling (HVAC) units.

SIPs have been used in construction for about 30 years. Eleanor Roosevelt commemorated one of the earliest SIPs buildings. Although they are not made on Long Island, there are about 150 manufacturers across the U.S. and SIPs are readily available to all builders.

To accommodate standard lumberyard sizes, SIPs come in thicknesses of 4, 6, 8, 10 and 12 inches and sizes up to 8 feet by 24 feet. For each building, SIPs are factory-cut to match the architectural plans. Lumber strips are fitted to each edge and around the windows and doors for secure attachment.

"Reduced labor costs offset the higher material cost of SIPs because the building goes up more quickly and easily," Chaleff adds. "This is especially true on Long Island where framing labor costs $12 per square foot, compared to $4 in the Midwest."

SIP is more resistant to outside air infiltration because it has no cracks. “The leakage in the average stick-built 2,000 square-foot house is equivalent to all the panes missing from one window year-round,” Chaleff says. Shutting out drafts – and noise – makes the house more comfortable.

Like plywood, Oriented Strand Board (OSB) gets its strength from thin layers of wood glued together, alternating the grain direction of each layer by 90 degrees. Each OSB layer is made of small, thin strands of wood aligned in the same direction. Unlike plywood, which uses the choice part of the best trees, the strands can be made from plantation-grown trees, branches, scrap lumber and trees not commercially viable for building.

The layers and the OSB strands are held together with adhesives. For those with reservations about glue strength, Chaleff observes: “If airplanes are held together with adhesives, we shouldn’t worry about houses.”

Stick and SIP buildings are both classified under the Type V building code which is based on fire-resistant properties and the time it would take to evacuate people from a burning building. SIP is ideally suited for houses and even large one-story buildings, but not skyscrapers or stadiums. Any structure in any architectural style that can be built with wood framing can be built with SIP. The exterior and interior will look the same as a frame building.

From the Middle Ages until World War II, wood frame construction changed little. The major advances occurred between 1840 and 1860 when 2x4s were mass-produced and transported long distances, thanks to the circular saw invention and railroad transportation.

Now, on Long Island, much of old growth lumber good enough for 2x4s is being used up. Framing wood is not produced here any longer. The grain of the Douglas fir trees used for this type of wood construction is too far apart causing twisting and warping. It doesn’t hold nails and screws tightly enough. “A house built from this lumber will rip itself apart,” Chaleff says. “We have to find ways to build more with engineered wood products.”

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