Goncrete evidence The case for concrete wall systems

A RE concrete wall systems, as prola,ponents claim, the "wave of the future" in residential construction?

By the year 2000, 7Vo of single family homes in the U.S. will be built with concrete wall systems, according to a market forecast by the Portland Cement Association.

Of the many insulating concrete form (lCF) systems. there are two prin- up, nobody has to worry about stacked lumber soaking up rain, cipal types. One uses hollow, interlocking polystyrene foam blocks that stack like masonry. The other uses foam panels with plastic ties to space them apart. Concrete is poured into steel-reinforced cavities in both systems to form walls of various thickNCSSES.

The stay-in-place foam forms supply insulation. Concrete supplies both insulation and strength.

Energy efficiency, earthquake and fire resistance, durability and maintenance ease have made ICFs popular in Europe for decades.

Contractor Michael Congdon has been acquainted with the ICF system for 25 years and recently completed two homes in the San Luis Obispo, Ca., area. Both are in the 2,600-3,000 sq. ft. range. One is Southwest Mission style, the other French Traditional.

Congdon finds the ICF system design flexible, quick to frame, and not victimized by adverse weather. During an El Niflo season, once the roof shelter is up, nobody has to worry about stacked lumber soaking up rain.

Costs of concrete and wood framing are comparable in the conventionally sized home, Congdon says. For large homes, ICF construction costs may average lVo-lo%o higher than wood.

In addition, according to the California Cement Promotion Council, substituting concrete walls for wood framing can save up to 20 trees per house.

Other studies, say the council, have shown that concrete walls reduce sound transmission by more than twothirds over frame construction.

California architect Craig Smith claims that lower energy costs argue in favor of concrete, since the heavy duty wall system absorbs heat for interior dissipation and is a superb insulator.

An energy cost study at Boston University compared 29 concrete homes to 29 wood frame homes of similar square footage and age. The ICF systems cut energy used for heating by about447o andcooling32Vo.

Smith is impressed with the ability of concrete to locate in any climate and on any terrain. He also calls it a "malleable material" that accommodates any design concept. "If somebody wants Southwestern adobe," says the architect, "he gets Southwestern adobe. If she wants Cape Cod, she gets Cape Cod."