An insulating concrete form (ICF) system uses hollow blocks made of polyurethane or polystyrene foam to form the foundation walls or even the whole house.

How it works

The foam blocks are fitted together like puzzle pieces or secured using C-shaped channels. Installers reinforce the forms with steel rebar, then fill the hollow chambers with concrete.

Electrical and plumbing lines are concealed within carved channels cut into the foam walls. Both the interior and exterior can be covered with any type of finishing product, including drywall, plaster, brick, stucco or siding.

Energy savings

The insulation value of a finished wall ranges from R-18 to R-26, and the solid concrete core virtually eliminates the cold drafts typical of wood-frame construction. This means most ICF homes have utility bills 30 percent lower than typical homes.

Other benefits

A typical four-inch-thick foam block wall is four to six times stronger than a conventional "stick-built" house, making it resistant to fire, violent winds and even earthquakes. In some areas, owners of foam-block houses may qualify for lower home insurance premiums.

The combination of high-mass concrete and permanent insulation will also reduce noise pollution, resulting in a quieter home.

Costs

The construction costs for ICF houses usually runs about five to seven percent more than wood framing, but the costs can be paid back in energy savings in two or three years.

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