What Are ICF’s?
Insulating Concrete Forms are basic forms for poured concrete walls. Unlike traditional concrete wall construction, which utilizes steel or aluminum forming panels that are removed after the concrete is poured, ICF formwork stays in place to become a permanent part of an insulated wall assembly. The lightweight forms, made of foam insulation, are either pre-formed interlocking blocks or separate panels with plastic ties. The left-in-place formwork not only provides a continuous insulation and sound barrier, but also a backing for drywall on the inside, and stucco, lap siding or brick on the outside.
Types of Insulating Concrete Forms
Although all ICFs are identical in principle, the various brands differ widely in the details of their shapes, cavities and component parts.
Block systems have the smallest individual units, ranging from 8″ x 1’4″ (height X length) to 1’4″ x 4′. A typical ICF block is 10″ in overall width, with a 6″ cavity for the concrete. The units are factory-molded with special interlocking edges that allow them to fit together much like plastic children’s blocks.
Panel systems have the largest units, ranging from roughly 1′ x 8′ to 4′ x 12’. Their foam edges are flat, and interconnection requires attachment of a separate connector or “tie.” Panels are assembled into units before setting in place – either on-site or by the local distributor prior to delivery.
Plank systems are similar to panel systems, but generally use smaller faces of foam, ranging in height from 8″ to 12″and in width from 4′ to 8’. The major difference between planks and panels is assembly. The foam planks are outfitted with ties as part of the setting sequence, rather than being pre-assembled into units.
Within these broad categories of ICFs, individual brands vary in their cavity design. “Flat wall” systems yield a continuous thickness of concrete, like a conventional poured wall. “Grid wall” systems have a waffle pattern where the concrete is thicker at some points than others. “Post and beam” systems have widely spaced horizontal and vertical columns of concrete, which is completely encapsulated in foam. Whatever the differences among ICF brands, all major ICF systems are engineer-designed, code-accepted, and field-proven.
Applications of Insulating Concrete Forms
Single-Family Homes – Since the early 1990’s, the use of ICFs in the U.S. housing market has skyrocketed. This is due to an increase in price and decline in quality of North American Lumber. In fact, according to data collected by the Portland Cement Association, it has become the fastest growing alternative to wood frame for above-grade perimeter wall construction. The number of single-family homes built from footing to eaves with ICFs has been approximately doubling each year. In 1997, about 8,000 to 10,000 above-grade ICF homes were built in the U.S. About one-third of all ICFs sold are used in above-grade residential construction.
Multi-Family Homes – Townhouses and condominiums represent a rising and significant application for ICFs. Due to the necessity for increased firewall protection and sound deadening between units in these structures, above-grade ICF walls are becoming an increasingly popular and cost-effective option for builders and developers.
Residential Basements – In cold climates, energy experts tell us up to 40% of a home’s heat loss is through the ground. ICFs create the perfect basement walls for locking out winter, and keeping more warm, heated air inside. ICFs have been used for decades in foundations and basements throughout North America. Currently, about one-third of all ICFs sold are used in residential basements.
Commercial Buildings – About another third of all ICFs are used in commercial construction, both for foundations and for above-grade walls. In addition to lowering the ongoing operating costs of the building due to the increase in energy efficiency, using ICFs for the entire structure can significantly decrease the construction cycle time, speeding up a project by weeks or even months. Commercial uses of ICFs – for hotels and motels, retail and professional buildings, warehouses, schools and churches, theaters, and others – are a rapidly growing application.
Where have ICF homes been built?
ICF homes have been built all across the U.S, in every region, and virtually every state. ICF homes are prized in the Northeast and Upper Midwest for their energy efficiency and comfortable indoor climate. Along the hurricane-plagued Eastern Seaboard and Gulf Coast, ICF homes are similarly valued for their durability and resistance to storms. In the Southwest, ICF homes keep their occupants much cooler in the summer and warmer in the winter. On the West Coast, ICF homes provide safety from earthquakes and fires.
In the provinces of Canada, the growth rate of ICF homes has exceeded even that of the United States. Spurred by government programs to encourage the construction of more energy efficient housing, more Canadian builders already know what their U.S counterparts are just now discovering: It is often less expensive to build with ICFs from footing to eaves than it is to build a stick frame house to the same insulation standard.
How to select an ICF system
Just as every brand of automobile performs the same basic function – getting you from Point A to Point B – so does every brand of ICF. However, just as you wouldn’t buy a new car without thoroughly understanding your own needs and thoroughly researching what is available, the same holds true for choosing a brand of ICF. What is the best system? Only you can really make that judgment, based on your individual needs.
The ICFA Member List has links to the websites of all members – these are the largest and most respected manufacturers/marketers of ICFs in North America. These companies will send you literature on their systems, as well as tell you if they currently have distribution and technical service in your area.
If you want some up-front guidance in your research, the ICFA and the Portland Cement Association have a number of excellent ICF brochures, books and videos, which are listed on our Publications page. These materials can take you through everything from generally comparing ICF brands to answering detailed engineering and technical questions. They are also indispensable reference tools for the building professional.
How to find an ICF contractor or builder
The ICFA Member List is a good way to locate an experienced ICF contractor. Some of the companies on the Contractor/Distributor portion of our list also act as a general contractor. However, if they do not, they can put you in touch with experienced local ICF builders and architects.
Another great source of local information is your state or provincial-level ready mixed concrete association. They would usually know where ICF homes are being built, and who the experienced ICF builders and contractors are in your area.