New ways to build.
In fact, the builder is now solidly sold on using ICFs on future projects ... and even convinced his concrete sub to switch once he saw its efficiency in action. "It took one super and a laborer just 25 minutes to set one course, including steel, of the [2,000-square-foot] basement footprint," says Steven Jones, founder and president of Merlin.
Already on a shorter-than-normal schedule to complete the home, the laborsaving virtues of ICFs enabled the walls to rise quickly while also creating an open shell, which allowed maximum flexibility in room sizes and layout and a full-span, recycled steel roof frame.
The ICFs also eliminated the plate line, an inherently problematic transition between concrete foundation walls and wood or steel framing, thus significantly reducing thermal loss. The self-insulated concrete, meanwhile, helped boost the overall efficiency of the exterior walls' thermal mass to R-50 without requiring any extra insulation. "It was 10 degrees cooler in the basement area even before we had the windows in," says Bart Jones, noting that ICFs also result in a deeper, straighter wall structure than he can hope for (or even afford) with sticks in a desert climate.
The innovative techniques didn't stop there, however. The design/build team also specified structural insulated panels (SIPs) for the roof, with the pre-insulated, oriented strand board-faced sections set between recycled steel girders of the roof frame--a process that took exactly one day to complete and was the only way to create the deep eaves over the upper level terraces. Light-gauge steel framing and a glass-mat, mold-resistant wall board complete the interior walls, making TNAH an example of forward-thinking--if not yet mainstream--structural materials.
Those systems, among other construction innovations featured in the house, also tie into van Straten's vision for the loft as a viable design and building option for more flexible and durable production housing. "The only way to combine the loft design with efficient construction is with industrialized housing techniques and systems," van Straten says, such as ICFs and SIPs. "We're not trying to change the world [with this house], but to build an awareness of materials and systems that address issues of depleted resources, durability, and longer life-cycle."
* Mold-resistant wallboard from G-P Gypsum uses a glass mat face instead of paper to impede mold growth. Circle no. 992.
* Light-gauge steel framing, sponsored by the Steel Framing Alliance, delivers straight walls, reducing service callbacks. Circle no. 993.
* Building America's IBACOS Consortium provided design consulting and energy analysis services toward achieving greater energy efficiency. The home achieved a home energy rating system (HERS) score of 90, thus qualifying as an Energy Star--rated home, and will use 46 percent less energy for space heating and cooling, hot water, and lighting than the builder's standard home. Circle no. 994.
* Structural framing connectors from Simpson Strong-Tie Co. boost seismic and wind tolerances. Circle no. 995.
In addition to creating perfect walls, lessening cycle time and labor costs, boosting energy efficiency, delivering built-in seismic qualities, and providing a solid, durable, and abundantly flexible exterior shell, ICFs combat what builder Bart Jones calls "monsters" in the housing industry: phantom problems and defects that threaten even the best builders. All but eliminating the possibility of mold growth and moisture damage, warped walls from green lumber drying in the desert heat, and other potential defects--while building faster and delivering a more energy-efficient house--is well worth the 3 percent to 5 percent premium the Jones brothers pay to use ICFs. "By the time you frame, for out insulate, sheet or shear a wood-framed wall you've made that cost back," says Steven Jones. The ICF system was supplied by Arxx Building Products (Circle no. 996), with support from the Portland Cement Association (Circle no. 997).
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|Title Annotation:||The New American Home 2004|
|Date:||Jan 1, 2004|
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