Insulating Concrete Forms (ICFs) give you all the benefits that have made concrete the material of choice for building worldwide: Solid, lasting construction that resists the ravages of fire, wind, and Father Time. But ICFs do plain concrete one better – or rather, two better – by giving you two built-in layers of foam insulation.

ICFs are hollow “blocks” or “panels” made of expanded polystyrene insulation (EPS) or other insulating foam that construction crews stack to form the shape of the walls of a building. The workers then fill the center with reinforced concrete to create the structure. There are more than 20 brands of ICFs in North America, each providing variations in design and materials.

For years, insulating concrete forms (ICFs) were used almost strictly for residential construction, but not anymore: the method is rapidly gaining popularity in commercial construction. Today approximately one-third of ICF structures are non-residential, according to the Insulating Concrete Form Association.

As with all concrete wall systems, structures made with ICFs can qualify for a high number of points toward certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED®) Green Building Rating System. By sandwiching a heavy, high-strength material (reinforced concrete) between two layers of a light, highly insulated one (EPS or foam) a wall is created many desirable properties fore creating environmentally friendly buildings.

Mass. The concrete walls of an ICF home have high thermal mass, which buffers the interior of a home from the extremes of outdoor temperature during every 24-hour cycle. This reduces both peak and total heating and cooling loads.

Buildings constructed with ICF walls have a more even temperature throughout the day and night. They have virtually no “cold spots,” and far fewer drafts. ICF walls have negligible air infiltration.

Energy Efficiency. The superior insulation, air tightness, and mass of the walls can reduce the cost of operating HVAC in the building by up to 40%. In addition, ICFs allow the installation of smaller (generally, less expensive) heating and cooling equipment. The high R-value combined with thermal mass means ICF walls exceed most energy code requirements.

If the building is like most buildings, it is using fossil fuel. By reducing the building’s amount of energy need to heat or cool the building, the ICF plays an important role in reducing the negative environmental impacts associated with fossil fuel use.

Increase indoor air quality. Air infiltration in an ICF home is minimal due to the continuous air barriers provided by the foam insulation and the concrete. Likewise, there are no convection currents within wall cavities. As a result these homes provide a healthy indoor environment. Nothing held within or ordinarily emitted by an ICF wall is toxic. The measurement of the air contents of actual ICF houses shows an almost complete absence of any emissions.

Fire resistance. Of all construction materials, concrete is one of the most resistant to heat and fire. Unlike wood, concrete does not burn. Unlike steel, it does not soften and bend. Concrete does not break down until it is exposed to thousands of degrees Fahrenheit—far more than is present in the typical residential or office building fire.

Experience shows that concrete structures are more likely to remain standing through fire than are structures of other materials. Concrete walls have also proven more resistant to allowing fire to pass from one side of the wall to the other. This is a significant benefit in areas where brush fires are common, or where high density zoning increases the risk of fire spread.

Durability. Concrete buildings survive high-force winds like hurricanes far better than wood or metal frame buildings. When properly reinforced, they should also withstand earthquakes well.

Locally Sourced Materials. The manufacturing process of portland cement, the binding element of concrete, is not tied to a certain region of the country and the materials involved in the process are readily available throughout North America.

Cost effective. ICFs are so efficient to build with and easy to use, that the cost of building an ICF house is comparable to that of an ordinary 2x6 wood-framed house. But you get so much more home for your money.

Sound attenuation. About one-sixth as much sound gets through an ICF wall compared to an ordinary frame wall.

Strength. The solidity of concrete construction reduces flexing in floors, as well as shifting and vibration from the force of the wind or the slamming of a door.