It’s no secret that ICF homes have very low “operational carbon” thanks to their superior energy efficiency due to the threefold “ICF effect”.
But what about the embodied carbon in an ICF home?
Concrete homes (and ICF houses included) are perceived to have higher high levels of embodied carbon, mostly due to the portland cement in the ready mix concrete.
But with the new technologies that are evolving in response to tightening energy codes, it’s now possible to build an ICF home with a far lower embodied carbon footprint.
In the post below, we’ll look at a case study of one such home, and give you a few tips for curbing the levels of embodied CO2 in your next ICF construction project.
Case Study – A Low Embodied Carbon ICF Home Profile
A recent Habitat for Humanity project in Will County, Illinois, shows just how possible it is to build ICF homes with a low embodied carbon content — as long as the builder is open to some degree of innovation.
In this home, the project team was able to reduce the carbon footprint through their choice of building components. Notably, the team opted for the following two sustainable construction materials:
- CarbonSense concrete from Ozinga Bros, Inc: Ozinga’s CarbonSense is a line of low CO2 cement, aggregate, and mix products. The Habitat for Humanity ICF home was built with the company’s ultra-low-CO2 concrete, which has roughly 40% less embodied carbon, and 74% less Global Warming Potential (GWP) than traditional mixes do. Despite the low CO2 count, Ozinga’s concrete performs as well as (or even better than!) conventional concrete mixes in terms of strength, durability, and set times.
- ICFs made with Neopor BMB: In addition to Ozinga concrete, the project team built this demonstration home with ICFs made with Neopor BMB. Neopor BMB is made with renewable feedstocks in addition to traditional ones, and thus comprise roughly 60% less embodied carbon than their non-BMB counterparts. Neopor BMB is widely available in Europe but is not yet commonly available in North America.
According to Gregg Lewis of the National Ready Mix Concrete Association, this Habitat for Humanity Home is “the most forward-focused [home] in terms of innovations and sustainability”.
What You Can Do to Reduce Embodied Carbon In Your Next ICF Project
As the project profile above shows us, slashing the embodied carbon content of an ICF home comes down to the choice of materials. So, here are a few construction materiality options you should consider if you plan on building a low-CO2 ICF home:
- Low-carbon concrete: You have plenty of options when choosing a low-carbon concrete mix for your project. You can choose a specially designed product like Ozinga, a waste-based concrete product such as Carbon Cure, or other sustainable alternatives available in your region. We’ve summarized a number of exciting low-CO2 concrete solutions in this post, so you can check if your local mix suppliers have any of them available.
- Neopor ICFs: ICFs made with Neopor have a slightly lower level of embodied carbon than their EPS peers, and substantially less CO2 than XPS. You can slash the CO2 content even more by opting for BMB Neopor, if it’s available in your location. Please note, Neopor BMB is not yet commonly available in North American markets, but supply will not doubt increase in the future.
- Fiberglass rebar: Fiberglass rebar has less embodied carbon than traditional steel reinforcement. And although it is a newer and emerging technology, it’s proponents feel it’s also stronger, lighter, and more resistant to corrosion than the conventionally used steel rebar.
- Insulation: If you’re only using ICF to build basement walls, make sure you choose a low-CO2 rigid insulation product for your superstructure. GPS and EPS have a drastically lower embodied carbon content than XPS, thanks to the blowing agent used in their production. So, going for a GPS-based insulation such as Halo, or EPS panels, instead of XPS is a no-brainer if you’re aiming to curb the quantity of embodied carbon in your project.
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Wrapping It Up
ICF homes are known for their exceptional energy efficiency and the consequent low operational carbon values that, over time, are regarded to offset their higher embodied carbon content when fossil fuels are used to heat and cool the home.
As we’ve seen from the post above, however, new innovative technologies make it very possible to reduce an ICF home’s carbon footprint through appropriate material choices. So, builders can now select low-CO2 materials and ensure that the ICF homes they build are as sustainable as they can be.
