The Benefits of Insulated Concrete Forms (ICF) Foundations

The Benefits of Insulated Concrete Forms (ICF) Foundations

The TC Legend Homes fellas put up the Lake Stevens house’s insulated concrete form (ICF) walls in the rain last week over the course of just (2) days! Dan said it went well since the soil had a good consistency to seat the Form-a-Drain footing, and the blocks went up fast, as per usual, since everyone likes stacking up Lego blocks!

A Net-Zero house is insulated on all (6) sides, and TC Legend builds with structural insulated panels (SIPs), so we have R-29 SIPs walls all around, R-49 SIPs roof above, and 4” R-20 foam under the slab-on-grade.

The edge of the slab also needs insulation, otherwise there would be a weak spot and heat would leak out through the slab perimeter, into the stem-walls (which are exposed to the weather).

We solve this problem by pouring the stem-walls into R-24 ICF forms which complete the insulted shell of this affordable Net-Zero home.

Concrete has been poured into foam wall-forms since the ‘80s. The hollow blocks go together like Legos with the required re-bar clipped inside, and once full of concrete, the Styrofoam block remains in place performing the job of insulation, and containing concrete while wet. The process is fast and clean, and has lower labor costs compared to traditional concrete forming.

We use NuDura R23.8 ICF blocks to form the stem walls, and retaining walls when we need them. The NuDura blocks are great since they concertina-down to transport. ICF blocks are available in many thicknesses with many variants for different construction requirements. We use 6” walls and usually only order inside-corners, outside-corners and 8’ straight blocks. The NuDura blocks have hard plastic structural strips that accept screws for siding and drywall.

The blocks sit atop the hat-channel that spans the footing form. At Lake Stevens we used Form-a-Drain footing form which, like the ICF’s does not need a form-board to be stripped-down after concrete is poured. The Form-a-Drain replaces 8” footer boards, is hollow, and drains water away from the foundation foot.

The Lake Stevens house has a 4’ stepped retaining wall up-slope and NuDura supply a very, very sticky vapor barrier to waterproof the stem-wall. TC Legend  Homes has a metal cap/ cladding system system that wraps the exterior ICF foam from the sill plate downwards below-grade with roofing metal, leaving no visually, or thermally exposed concrete.

ICF’s are great for us! They perform two functions: (1) insulation, and (2) concrete form, they are a smart solution for our thriving Net-Zero, and increasingly Net-Positive SIPs housing in Washington state!

TC Legend Homes: Typical SIPs wall ICF Foundation

 TC Legend Homes: Typical SIPs wall Insulated Concrete Forms (ICF) Foundation
Lake Stevens, Washington SIPs ICF
Lake Stevens, Washington SIPs ICF

2019 Summer Update

2019 Summer Update

TC Legend Ski to Sea team

News since our last update:

  • We found out we won the Residential Energy Services Network (RESNET) “Cross Border Challenge” award for Net Zero American Home Builder. This was for having a HERS Index Score of negative 25 on our Bellingham Affordable Net-Positive Home! Big thanks to Elizabeth Coe, our go-to for third-party certification!
  • We fielded our first-ever Ski to Sea team!
  • Sustainable Connections featured a recent detached accessory dwelling unit, which they dubbed “Gentle Density,” in the NW Green Home Tour.

  • We updated our Portfolio with some recent projects. Links to each of them are here:

  • The Department of Energy just recently let us know we won another Housing Innovation Award in the Custom for Buyer Category for the Whatcom County Net Positive (above).

 That’s it for now – enjoy the rest of your Summer, and we’ll touch base again soon!

2018 Year in Review

2018 Year in Review

Here at TC Legend Homes, we are excited to ring in the New Year! We kept busy in 2018, but we were not as active as we would have liked in keeping our “fans” updated on our recent projects. So, while we’re committing ourselves to doing better in the future, this post is an attempt at bringing everyone up to speed on some of the happenings of 2018 in a (relatively) short summary:

Homes:

  • One home completion (started in 2017) in Seattle.

  • Four complete home builds; two in Bellingham, one in Redmond, and one in North Bend.

  • Construction initiation on two ADUs; one in Sumas, and one in Bellingham.

  • All projects were Built Green 5-Star Certified, EPA Indoor airPLUS certified, and met DOE standards as Zero-Energy Ready Homes.

Events:

  • Ted presented at the Built Green Conference 2018 in Seattle. He shared the podium with homeowners Andri Kofmehl and Veena Prasad. Their topic, Bridging Innovation and Affordability: How to Build the Greenest House Possible Without Compromising on Aesthetics or Breaking the Bank, featured our 2017 Emerald Star home. More details on this can be found at this link to our portfolio.

  • Craig and Thad did a little San Diego couch surfing to attend a Builder’s Round Table, composed entirely of 2018 Department of Energy Housing Innovation Award Winners, where we learned a little about the future of high-performance building.

  • We participated in the Whatcom County Showcase of Homes, featuring the second home shown above – a great example of an affordable net-positive home in Bellingham. You can also read more about it in our portfolio.

  • Ted and Thad spoke at the Northwest EcoBuilding Guild’s annual Green Building Slam about how building net-positive can actually make it easier to afford more home while preserving quality of life.

  • We “expanded” our business operations into a SIPs Tiny Office (above).

  • Ted wrapped up his speaking engagements in December, at the Sustainable Connections Green Building Slam, with a talk about why we need to embrace sustainable building – because Our Kids are Going to Need a Place to Live.

Accolades: