Here is an introduction to insulating concrete forms for contractors seeking the basics of this construction application.

In the past decade, scientists have claimed that rising temperatures and warmer-than-average winters are proof that North America is feeling the effects of global warming. Just don’t tell that to the millions of North Americans who experienced one of the coldest and most brutal winters in recent history. From ice storms in Tennessee and North Carolina to massive snowstorms in the Rockies, Midwest and Northeast, it was a frigid and severe winter for almost everyone in North America.

However, more than 100,000-plus insulating concrete form homeowners throughout North America experienced a different winter behind the comforts of their ICF walls.

Advancements in technology and innovation, as well as customer loyalty, have rapidly propelled ICFs into a residential market phenomenon. The above-grade residential market for ICFs increased from 1.0 percent in 1998 to 2.7 percent in 2001, according to the National Association of Home Builders. Additionally, the Insulating Concrete Form Association and Portland Cement Association predict ICFs will account for more than 8.0 percent of the above-grade residential market by 2005. With energy legislation currently before Congress providing tax credits to contractors that build energy-efficient homes, the ICF market share is poised to make significant gains in the coming years.

ICFs can be used on commercial, institutional and residential applications.

The concept

ICFs are insulated forms for poured concrete walls that stay in place as a permanent part of the wall assembly. The forms, made of foam insulation, are either pre-formed interlocking blocks or separate panels connected with plastic or metal ties. The left-in-place forms not only provide a continuous insulation and sound barrier, but also a backing for drywall on the inside, and stucco, lap siding, or brick on the outside.

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 inches by 1 foot 4 inches (height times length) to 1 foot 4 inches by 4 feet. A typical ICF block is 10 inches in overall width, with a 6-inch 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 foot by 8 feet to 4 feet by 12 feet. 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 inches and in width from 4 to 8 feet. 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 are completely encapsulated in foam. Whatever the differences among ICF brands, all major ICF systems are engineer designed, code accepted, and field proven.

ICFs offer high energy efficiency.

The ICF experience

Market share and benefits related to ICF homes only tell a small portion of what motivates people to purchase an ICF home. The ICF story is a mixture of customer loyalty and brand identity that surpasses the benefits of living in an energy-efficiency, disaster-resistant structure. Ask most people what comes to mind when they think of living in a concrete home, and they say “cold,” “drab,” and “prison-like.”

Compare that with the comments of those living in an ICF home and there’s a sharp contrast. ICF homeowners boast about their comfort level, the love of their home, how much they save on their energy bill and how they would never live in any home but an ICF. Asked recently about his ICF home, John Ware, of Denver, says, “I built an ICF home for my family in 1999 and have enjoyed the benefits for more than four years. I cannot imagine living in an ordinary house ever again.”

So, what’s behind the rapid increase in market share? As I speak with ICF homeowners throughout North America, it never ceases to amaze me how closely they identify with living in and owning an ICF home. They also give high marks for energy-efficiency, quality, comfort and rock-solid performance.

The general contractor

Equally important in the success of a well-built ICF is how it is installed. The proper consolidation of concrete in an ICF can make the difference between an extremely durable, energy-efficient home and something that should be targeted for the local dump. Since the placement of concrete is the most important component of the ICF construction process, contractors must take extra care to do their homework on the ICF installer. Currently, there are many resources for hiring experienced ICF crews. The Insulating Concrete Form Association lists those who can install ICFs for general contractors. Additionally, the ICFA has a joint training program with the United Brotherhood of Carpenters, which many UBC apprentices and journeymen have successfully completed.

John Vogstrom of Vogue Homes, of Twin Cities, Minn., has been working with ICFs for the past five years.

“I have extreme confidence in the ICF system,” he says. “With advancements over the past several years, it really is a well thought-out building system.”

As for the strength of the market, Vogstrom says that demand is high. He began participating in the local Parade of Homes in 2001 and has found it to the best venue to demonstrate firsthand the benefits associated with ICFs.

“Before the 2001 Parade of Homes I was building approximately 10 percent concrete homes but I am now building 95 percent ICF homes and project that virtually all of my future building will be with ICFs,” he adds.

The finishing contractor

ICFs are one of the most versatile building systems available, and virtually any type of exterior finishing system can be used. One of the best and most reliable for ICFs is acrylic finish. Over the past several years, a great deal of finishing contractors have been turning to ICFs because of its solid substrate, limiting the risks of failure associated with other types of building systems.

Calvin Ladd of Titan Walls, located in Twin Cites, Minn., has been installing acrylic finishing systems for the past 10 years, and he now prefers working exclusively with ICFs.

“ICF and acrylic finishing systems absolutely creates the most beautiful exterior available,” explains Ladd. “It is simple to adhere, less labor intensive and can be installed in sections without complicating the project.”

Vogstorm agrees, adding, “ICFs and acrylic finishing systems are a perfect match.”

As for the education and experience required for installing acrylic finishing systems on ICFs, it is relatively small.

“For experienced finishing contractors, the learning curve is relatively small,” Ladd says. “Since I had experience working with other types of building systems such as wood and steel, ICFs were fairly easy to learn how to finish.”

To share ideas and teach others, Ladd routinely participates in a local education seminar sponsored by Cemstone, a ready-mix concrete company located in the Twin Cities area that offers ICFs and concrete services to customers.

The ICFA represents the ICF industry and is a first step in gathering additional information concerning ICF projects. The ICFA offers contractors several different publications on the ICF construction process, and the ICFA Web site ( is filled with information about ICF systems, as well as ICFA member listings. Additionally, the Portland Cement Association ( is also another source of useful information.