Home Built With Insulated Concrete Forms in Riverhead for Habitat for Humanity

Several new Habitat for Humanity homes have risen on the East End over the past couple of years, with the progress typically marked by a wall-raising ceremony. But the scene was quite different on Thursday, December 7, at the Riverhead construction site for a Habitat home on Oak Avenue.

Rather than a crew of volunteers lifting wood framing and securing it into place, on this build site the boom of a concrete pump truck was aloft over insulated concrete forms. As a cement truck poured wet ready-mix concrete into the pump truck, a crew aimed the boom to deliver concrete inside the forms, which are made from expanded polystyrene and will become permanent parts of the house’s walls, sandwiching the concrete.

Insulated concrete forms, or ICF, are not new technology, but ICF construction is gaining prominence of late and commanding a larger market share of homebuilding as demand for efficiency and resiliency in new homes becomes stronger.

The Riverhead home, in addition to being a charitable effort to provide a yet-to-be-selected family an affordable home, is also something of a showpiece for ICF construction and related industries.

It is the work of a coalition that includes the Insulating Concrete Forms Manufacturers Association, the National Ready Mixed Concrete Association, the American Concrete Pumping Association and Habitat for Humanity International.

“Those four organizations came together with the idea that we were going to build 50 concrete homes or ICF homes in 50 states,” said Micah Garrett, the chief operating officer of BuildBlock Building Systems, one of eight members companies in the Insulating Concrete Forms Manufacturers Association that is taking part in the effort. “So this project right here is the project that is taking place in New York.”

According to the National Ready Mixed Concrete Association, though the partnership planned for 50 homes over five years, it currently has 76 homes in various stages of construction in 33 states in just under two and half years.

BuildBlock Building Systems is headquartered in Oklahoma City, Oklahoma, and has manufacturing facilities across North America. The forms for the Riverhead project were made in Massachusetts.

“This form of construction has been around since the 1980s,” Garrett said. “It continues to gain popularity.”

The insulated concrete forms are made from smaller pieces — both straight and corner pieces — assembled into the shape of a house’s walls, with braces put in place where the windows and doors will eventually go.

Garrett referred to the individual pieces as “blocks,” and said the building method is similar to masonry, in that the blocks are stacked up. But rather than being stuck together with mortar, these blocks click together, much like Lego blocks. Once the forms are in place, a crew fills the forms using the concrete pump and boom, which allow them to get the concrete exactly where it needs to be.

The forms have the appearance of a foam cooler or foam packaging material.

“It’s the same material that’s often used in packaging applications, but we’re using it in a construction application,” Garrett explained. “… You have two foam panels that are connected with a plastic web tie that you stack up in the shape of your wall. You put your reinforcing bar, and then you fill it up with concrete. So what it does is, it gives you a structural concrete wall that’s insulated on both sides.”

Each foam panel is 2.5 inches thick, providing 5 inches total of insulation, with an R-value — the measure of insulation’s ability to resist heat traveling through it — of about R-22. That’s at the top of the recommended range for insulating walls.

Between the concrete wall and the foam forms, a building is really airtight and well sealed, Garrett said, noting that the concrete itself also will slow energy transfer.

“Think of it almost as like putting a concrete wall inside of an ice chest,” he said. “You’re putting foam on either side of it. So that wall doesn’t want to change temperature very quickly. So a lot of times this wall will perform at a higher R value than just an R-22.”

The Riverhead house’s walls have a 6-inch concrete core, which Garrett said is common in residential applications, though the forms can range from a core of 4 inches to 12 inches or even more.

The foam blocks have integrated furring strips spaced vertically every six inches, where siding and other exterior finishes can be attached.

“In this instance, they’re going to be using Hardie Board siding,” he said. “So they will screw the Hardie Board directly to those furring strips.”

Drywall and other interior finishes will be attached to the furring strips on the opposite side.

In addition to energy efficiency, another benefit of ICF construction is disaster resilience, according to Garrett.

“The structure we’re building here is going to be very, very strong, and it’s common that these are also built in coastal areas, where they’re prone to hurricanes,” he said. “These have a very, very high wind rating as well. So in an area like Long Island that occasionally experiences hurricanes, this home is going to be very, very strong in those types of events.”

Garrett said it took two days to get the foundation in, and then after the floors were completed, it took four days to do the forms for the walls. The concrete pour only took one afternoon.

“After 24 hours, it’s going to be pretty solid, and then you really want to wait about 28 days for concrete to get its total strength,” he said, though he added that the house will be ready for roof trusses to go up within a couple of days of the pour.

He encourages others to think about how structures can be built with greater energy efficiency, more sustainably and be more resilient. “Because in today’s changing climate, the reality is that our housing stock, we want to make sure that it’s resilient,” he said.

ICF construction is also noted for being sound dampening and resistant to mold, rot and pests.

The participants in Riverhead in addition to BuildBlock include Our Rental Pumps, Nicolia Ready-Mix and Habitat for Humanity of Long Island.

“We’re real blessed, because we’ve been chosen to represent New York State,” Habitat for Humanity of Long Island CEO Jimmy Jack said during a dedication of the house.

The house will be sold with an affordable mortgage to an income-qualified family.

“The apex of the entire mission is when we place a beautiful family in this house,” Jack said.