Currently Reading

Building for Sustainability, One Block at a Time


Building for Sustainability, One Block at a Time

The 2021 Sustainable, Healthier Home kicks off with a cost- and labor-efficient structural system 

By Nick Vaccaro July 14, 2021
EEBA ICF installation
Ohio builder Charis Homes uses insulated concrete forms (ICFs) to build the Sustainable, Healthier Home in collaboration with Pro Builder Media and the Energy and Environmental Building Alliance. | All photos: Cody Miller

The year-long rise in lumber prices has renewed builders’ interest in alternative structural solutions, from concrete block and steel to more “niche” systems, such as insulated concrete forms, or ICFs.

That was certainly the case when Charis Homes, an Ohio builder focused on the 55-plus market, signed on to build the Sustainable, Healthier Home in collaboration with Pro Builder Media and the Energy and Environmental Building Alliance (EEBA).

“With the high costs of lumber, we have seen a savings of approximately $2,000 in materials,” says Glenna Wilson, founder and owner of Charis Homes. But ICF technology isn’t new to Wilson or her trades. “I’ve trained my framing contractor in ICF installation, so I don’t see an increase in labor costs from using them,” Wilson says.


The 2,769-square-foot, single-level, three-bedroom, three-bath home also benefits from the inherent insulating value of the ICF system. By design, the lightweight, interlocking blocks serve as both the poured concrete forms for the home’s perimeter walls and provide 2½ inches of expanded polystyrene (EPS) foam to insulate the interior and exterior walls, respectively—an overall thermal value of R-26, or about 58% more efficient than a wood-framed wall.

EEBA ICF wallsEEBA ICF walls and corner

The system also serves as an air barrier and vapor retarder, eliminating the need—and cost and time—to purchase and install those products separately to achieve the same performance. “A big plus with ICF is there is no thermal transfer in the ICF walls or air infiltration,” Wilson says. “The benefit is fewer allergens entering the home, making it a healthier home.”

That’s important, as Wilson and her team work to deliver a Zero Energy Ready Home for buyers who often are cost-sensitive and demand a comfortable and healthier indoor living environment


Building With Insulated Concrete Forms

Despite a 50-year track record in Europe and being marketed in the U.S. since the late 1980s, ICFs remain a mystery to most home builders and their trades. The system occupies a relatively tiny share of the new residential construction market, with less than one-quarter of 1% of above-grade walls and a 2.6% share of below-grade walls among new homes built in 2020, according to the most recent Annual Builder Practices Survey from Home Innovation Research Labs.

To be sure, the ICF system has its nuances, but upon deeper examination, it appears relatively simple. The 16-inch-high by 48-inch-long blocks—far larger (and lighter) than a standard concrete masonry unit (CMU)—are fitted with rebar as they are stacked along the home’s perimeter footings, providing structural strength and stability for the concrete poured into the ICF cavities. 

Wilson’s installers also know well enough to spec the proper slump of 3,000 psi concrete containing 30% fly ash vibrated to clear voids as it fills the cavity, and use stabilizers to prevent rare “blowouts” along the surface until the concrete starts to cure, eventually reaching 4,000 psi strength. 

EEBA ICF walls being built

And while corners used to be tricky, today’s ICF manufacturers offer form configurations for just about every angle and turn. As with CMU-built walls, ICFs require wood window and door bucks to fasten fenestration. At the top of the walls, Charis Homes embeds anchor bolts 1 foot off of the corners and every 4 feet in along a wall’s length to accept and secure plated roof trusses.

EEBA ICF corners and window bucks


Finishing ICF Walls

Once cured, ICF walls can receive various finishes, including traditional siding, stucco, and stone on the outside, and drywall or other wall finishes inside, as well as connections to interior framing. For mechanical runs—namely wiring and plumbing—Charis Homes inserts PVC sleeves into the ICF blocks prior to the concrete pour to serve as chases; other common techniques include scoring chases into the interior side of the foam walls (then concealed behind the finishes), running wires and pipes through the wood-framed roof and interior walls, and/or containing MEP runs in narrow chases along the floor or ceiling.

“ICF is a superior product all the way around,” Wilson says. In addition to its insulating and air-sealing values, “it offers 4-hour fire resistance and a high level of soundproofing against noise pollution. It allows me to be competitive in providing the best homes possible to my customers.”

Sustainable, Healthier Home sponsors:

EEBA Sustainable, Healthier Home sponsors


Related Stories


Architect Talks Details Behind His Long Island Passive House

On HorizonTV this week, watch architect Wayne Turett, principal of New York-based The Turett Collaborative, discuss his passive house project in…

Sponsored Roost - Nudura ICF Project on Bainbridge Island
Building Envelope

Thoughtfully Designed Homes With ICF

Houses designed with authenticity, thoughtfulness, and materials that were beneficial to both the residents and the environment. ICF construction with a tight building envelope.

Building Envelope

10 New Siding Products You Should Know About

Stucco and vinyl may still be the kings of exterior cladding, but lately there has been a steady flow of options offering a combination of low maintenance, durability, and good looks.


More in Category


Create an account

By creating an account, you agree to Pro Builder's terms of service and privacy policy.

Daily Feed Newsletter

Get Pro Builder in your inbox

Each day, Pro Builder's editors assemble the latest breaking industry news, hottest trends, and most relevant research, delivered to your inbox.

Save the stories you care about

Lorem ipsum dolor sit amet lorem ipsum dolor sit amet lorem ipsum dolor sit amet.

The bookmark icon allows you to save any story to your account to read it later
Tap it once to save, and tap it again to unsave

It looks like you’re using an ad-blocker!

Pro Builder is an advertisting supported site and we noticed you have ad-blocking enabled in your browser. There are two ways you can keep reading:

Disable your ad-blocker
Disable now
Subscribe to Pro Builder
Already a member? Sign in
Become a Member

Subscribe to Pro Builder for unlimited access

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.