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Building Matters

Measuring Embodied Carbon

Tools for determining a project's up-front carbon emissions to help inform materials selection—and the challenges of employing them

This straw-bale house designed by Arkin Tilt Architects is a net-zero energy design that also uses materials that sequester carbon. A new calculator aimed at helping designers and builders select materials with low embodied carbon is due for release at the end of February. Photo courtesy Edward Caldwell.

A Canadian builders’ group says it is nearly ready to unveil its long-awaited database on embodied carbon in building materials, giving builders and designers one more tool for reducing the oversized contribution the industry makes to global climate change.

The BEAM calculator has been in the planning and development stage since 2018 under the direction of Chris Magwood, the executive director of a sustainable building school in Ontario called the Endeavour Centre. Barring any unforeseen snags, Magwood says, the software will be available at the website of Builders for Climate Action by the end of February.

“It turns out that getting into the software business is just as hard as the house contracting business,” Magwood said in a telephone call. Three people have been devoting most of their time to wrapping up the software while another half-dozen have been reviewing and critiquing the work and otherwise trying to wrap things up.

The release comes at a time when an increasing number of architects and builders are shifting their attention from “operational carbon,” meaning the greenhouse gas emissions connected with heating and cooling buildings, to “embodied carbon,” the emissions that can be attributed to manufacturing and transporting building materials such as concrete, steel, wood, and plastics. As Magwood and others have argued, as operational carbon declines with steady improvements in building efficiency, embodied carbon in building materials becomes more important in the near term. To keep global warming under 1.5ºC, the point at which scientists fear irreversible change takes place, builders will have to start using materials with less embodied carbon as well as those able to sequester carbon.

BEAM stands for “building emissions accounting for materials” and is intended to help builders and designers estimate greenhouse gas emissions in materials they use to build a house. It will be among a…

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  1. nickdefabrizio | | #1

    This is a great first step. We have to do this if we are serious about climate change....

    A complete system would also include all the embedded carbon in the infrastructure needed for a particular house. Where I am people are putting in 1000 foot driveways to get to their energy efficient new home with the 40 foot concrete swimming pool......and clearing trees to do it...

    1. charlie_sullivan | | #3

      Another piece to include is the tradespeople driving trucks to the site each day. That might seem inevitable, but there are options to consider such as parking a trailer at the site for the duration of the project and driving there in small cars, possibly car/vanpooling to bring workers to a site if it's in a different region from where most of them live. And increasing the use of factory-built modules or panels.

      1. nickdefabrizio | | #5

        Good point!

  2. Expert Member
    ARMANDO COBO | | #2

    Really good article, Scott. Thank you for an eye opening summary.
    Carbon-neutral homes are designed with material and energy reduction in mind. This encompasses FREE passive solar design, low or lower carbon material production and selection, systems and processes that help reduce energy consumption, and a home that produces the same amount of renewable energy that it expends, creating zero carbon emissions.
    Limiting carbon-intensive materials by avoiding products with high carbon footprints like steel, concrete, aluminum, plastics, and foam insulation, and/or a thoughtful use is essential.
    Choosing lower carbon alternatives to build structures by utilizing optimum value engineering, wood framing efficient structural trusses and engineer wood products. Same with eco-friendly, sustainable and recyclable material claddings, like wood, brick or siding.
    Maximize your structural efficiency applying optimum value engineering, wood framing efficient structural trusses and engineer wood products.
    The bottom line is that today, with little time spent deliberating about the right building processes, selecting low-energy materials and adding renewables to our homes, we can easily achieve over 60% savings in our homes total embodied energy and carbon reduction, and a lot more with on-site renewables.
    The best part of designing and building Zero Energy Ready homes is that we have most of our clients achieving this level of efficiency, healthy homes and lower carbon footprint for no additional cost, and few for about 1% more. No excuses!

    1. GBA Editor
      Kiley Jacques | | #4

      Armando, do you track carbon in your projects? If so, what software do you use?

    2. Expert Member
      ARMANDO COBO | | #6

      @Kiley – Personally, I don't. We did had a couple of projects awhile back that the Homeowners hired consulting firms to do complete LCA analysis. Base on their information, we chose regular materials that have low carbon emissions. I do recall that both carbon emission reductions were around 60%. They also noted that with one house having PV at 95% annual consumption and the second at 106%, most of all the carbon emissions were offset.
      The full cost of doing an LCA on all projects, is unfortunately, something few residential clients are willing to pay for. The way I design houses today, with all materials and systems being almost the same as those two houses, I’m pretty confident we’re achieving similar goals.

      1. nickdefabrizio | | #7

        But in the end isn't this mostly about reducing concrete and steel? of course, one would want to reduce waste of all sorts where ever possible, but ultimately, isn't most of the imbedded carbon in concrete and steel?

        1. charlie_sullivan | | #8

          Mostly, but foams can also contribute. Majorly, with the wrong blowing agent, or less dramatically through their polymer content.

      2. GBA Editor
        Kiley Jacques | | #12


        I interviewed Stacy Smedley last week. She is one of the creators of the EC3 carbon calculator. She walked me through the software a bit--it was edifying to learn how products compare, how many categories there are to measure, what kind of emission reductions are possible, where to source vetted products, and how much work goes into gathering and sharing this data (for free). It was a hopeful-feeling conversation. I mentioned as much to Scott Gibson, who made an excellent point: "The key will be builder interest."

      3. Expert Member
        ARMANDO COBO | | #13

        Kiley - As you found out, one can spend a lot of time doing the research, so it takes a client, homeowner or Builder, heavily invested in carbon reduction, to hire someone to do all that work, and pay for it. I know I don't have the time for it, and if I did, I definitely wouldn't do it for free.

  3. awilliamfrederick | | #9

    More cheerleading for my builder peers here than trying to promote, but I started an on-shore U.S. company making offsite compressed straw panels this past year, and the market demand is through the roof, though straw requires some interesting problem-solving to make a homogenous panel. so- PLEASE, guys and gals, apply your ingenuity and make some too, the market is there. There really isn’t a better bang for your embodied carbon buck than straw.

    1. Expert Member
      MALCOLM TAYLOR | | #10


      I don't know a lot about it, but something like what you are doing would seem to me to be exactly what straw needs to achieve more widespread use. Maybe GBA will do a feature on it?

      1. GBA Editor
        Kiley Jacques | | #11

        Malcolm, I had a similar thought and did a little poking around to see what I might learn about Andrew's product. I wasn't successful. Andrew, if you'd like to chat, email me at [email protected].

        1. SidneyN | | #14

          It's too bad your latest GBA article about Andrew's panels is behind the GBA Prime paywall, as I have been interested in strawbales and worked on a couple of stawbale buildings in Maryland about 10 years ago. The main issue with straw is the R-value is only about 1.45/inch (based on ORNL test in 1998). I look forward to hearing how Andrew's panels test.

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