Insulating Concrete Forms for Residential Construction
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May 1997, 132 pages
Insulating concrete form (ICF) construction increases comfort, saves energy, muffles exterior noise, and requires less maintenance than standard techniques, a new HUD-sponsored study shows. Insulating Concrete Forms for Residential Construction reports on a demonstration program coordinated for HUD by the National Association of Home Builders (NAHB) Research Center on the use of this alternative structural material for single-family houses.
ICFs can replace conventional stud construction for basement and side walls. The forms usually consist of concrete between polystyrene foam, although other form materials such as polyurethane, recycled wood, and cement mixtures are sometimes used. There are three general types of ICF construction: flat ICF wall, where the poured concrete surface is flat; waffle grid, where the concrete has varying thickness; and open grid, where the concrete forms a grid.
The forms--which come in many shapes and sizes--usually fit together horizontally and vertically, using interlock tongue and groove joints. They are assembled at the building site, where concrete is poured into the open spaces in the ICF wall system. Plastic or metal ties hold the forms together, if needed. After the concrete sets, the form material remains in place, insulating the wall. Interior walls are covered with drywall as a fire-retardant finish surface. Exterior walls are covered with conventional siding.
Builders have found that structures using ICF systems had higher costs than conventional construction--raising the sales price between 1 and 5 percent. Construction crews needed some training but became comfortable with the new techniques by the third form-built house. The houses sold readily, and builders expected to continue using this type of construction.
Homeowners who bought the demonstration houses reported being pleased with their homes. They said they heard less street noise and--since the structures had less air leakage--they felt more comfortable and used less energy for heating and cooling.
Historically, the construction industry has often hesitated to explore approaches that differ from conventional practice. However, recent materials advances, technical developments, supply concerns, and economic uncertainty have prompted HUD to commission a review of alternative structural materials for homebuilding. By building and evaluating demonstrations of alternative techniques, HUD can help to identify and disseminate practical technologies.
Content updated on 7/20/2009