CFA Awards

Greenbuild Legacy Project
Category: Above-Grade Concrete Home

This project is a case study designed to demonstrate, through the cooperative effort of various local consultants, product manufacturers, and volunteers, the idea of next generation, affordable housing. Two homes were constructed in this effort, Legacy A – an all concrete home constructed with insulated concrete forms (ICF) and Legacy B – a more traditional, lumber-framed home.  Legacy A was built for GreenBuild based on a partnership with Bank of America and Habitat for Humanity Lake County and Legacy B was completed soon after to continue with the research.

Both homes have the same floor plan and appearance, differing only in the two construction methods. Legacy A, the GreenBuild Legacy Home project, is an entire envelope of ICF construction.  Legacy B, the second home built as an instructional opportunity for GreenBuild attendees, consisted of 2x6 framing, one (1) inch extruded polystyrene (XPS) insulated wall sheathing and two (2) inches of closed cell spray foam on the interior stud cavity.   Both homes were targeted to achieve LEED for Homes Platinum. Actual construction cost data and performance will be tracked and published for both homes once both are complete.

“The home will achieve LEED Gold certification for sure and a 95% probability of LEED Platinum,” states Eric Barton of Biltmore.  “All the final documentation and points are not yet final but are in the works. I can’t wait for the blower door results between the stick framed & this concrete home!”

As a concrete home, the structure is 2,780 square feet with 222 linear feet of concrete wall and totaling nearly 60 cubic yards of concrete.  Walls, including gable walls for the roof, have 6.25-inch concrete cores.

“There was as section of 17 foot tall wall above grade which we poured all in one lift,” stated Barton. “The pump truck operator stated that he had never seen a stronger ICF wall system during a pour.”

The results of blower door testing is perhaps one of the most striking differences between these two projects.  Since both were designed for LEED Platinum compliance, operational efficiency was to be a focus.  As tested by Jim Cavallo of Kouba-Cavallo Associates, Inc., Legacy A achieved 1.32 ACH @ 50 pa while Legacy B managed only 3.03 ACH @ 50pa.  “I’ve been involved in other homes done with concrete including precast.  This is the tightest home I have ever tested.”, states Mr. Cavallo.  “It was a great example for many home builders, not just those for affordable housing but for upscale homes of all types and sizes. 

You can build very tight and energy-efficient with very good indoor air quality using controlled ventilation.  Since the home was designed to be so tight, a heat recovery ventilator was used.  It operates continuously so you can make the envelope very tight and still maintain good air-flow and ACH.  You take advantage of the air leaving to help condition the entering outdoor fresh air.”

Eric Barton is a CFA Certified Concrete Technician, and member of CFA.  His company, Biltmore Insulated Concrete, Inc. offers fellow CFA members discounts on the Logix ICFs materials which Biltmore distributes nationwide. 

Visit their website at http://www.biltmoreicf.com or call them at (847) 681-1973 for more information.

 

 

Winning Contractor

Biltmore Insulated Concrete, Inc.

Project Specs

2,780 square feet with 222 linear feet of concrete wall and totaling nearly 60 cubic yards of concrete