They say the typical new home lasts a lifetime, roughly 70 to 100 years.
“One hundred years? I’m thinking three hundred years,” declares Rob Lochner, describing the expected life of a pair of single-family net-zero homes he worked on last year.
The interesting part? Each home was assembled, insulated, and sheathed “… within a week, a lot faster than traditional framing,” he says.
Lochner should know. As the construction director for the Santa Fe chapter of Habitat for Humanity, he has managed construction on more than 60 homes the last 11 years, all frame stucco except for the pair last year. All Santa Fe chapter Habitat homes meet net-zero standards.
“Our in-house design person used the same basic floor plan we used for other net-zero projects. One home is four-bedroom, about 1300-square-feet, the other is three-bedroom, 1250-square-feet,” Lochner explains.
The major difference is the building system. Thanks to a grant from several national organizations, Lochner, his chapter team, and a group of volunteers ranging in age from 16 to 84 constructed the homes out of ICF, short for insulated concrete form. ICF is a highly evolved building system that uses foam blocks stacked Lego-like to create rebar-reinforced, self-insulating cast-in-place concrete walls.
Lochner admits he was anxious about trying something new, especially with volunteer help. “I was pleasantly surprised by how smooth it came together. Our folks enjoyed it. Setting the foam blocks isn’t physically demanding at all,” Lochner says of the building system.
ICF surprised him in other ways, too. Take hanging drywall, installing kitchen cabinets, and running conduit and electric throughout the house.
- Interior Walls. “It’s easier to work with ICF,” Lochner reports. “The blocks are set up for it. You don’t have to use a stud like with frame built. With ICF there’s a purchase point every six inches and other mega purchase points for heavyweight hanging. Hanging material isn’t a big deal.”
- HVAC. The Habitat team specified a mini-split ductless system that delivered 6000 to 8000 BTUs. “That’s all the heating and cooling load they required with standard eight-foot ceilings,” he says.
- Insulation. The foam block composition means two inches of insulation on both sides of six inches of concrete, a formidable continuous and unbroken thermal barrier. The aim is zero utility expense use for the all-electric homes.
- Resilience. This is where ICF shines. “Anywhere you’re building where tornadoes, hurricanes, heavy moisture, and wildfires are threats, ICF is the go-to material,” Lochner observes.
The thought a net-zero home that might shelter families in the year 2323 delights the environment-first construction pro, especially given New Mexico’s Pueblo architectural heritage. “We shouldn’t be replacing things,” he says. Lochner is also encouraged by the strides the ready-mix industry is making in reducing carbon content. Innovations in fiberglass and carbon fiber rebar also help support sustainability.
Lochner isn’t shy about placing his bet: Plans are underway for a threeplex and duplex using ICF. “I can’t think of a better way to soundproof and fireproof the common wall.”
Learn more about how ICF extreme longevity, installation speed, and other advantages can benefit your next project.