Sustainable Projects

Karuna House Plans to Test LEED, Passivhaus and Minergie-ECO Certification Compatibility

Oregon-based developer Hammer & Hand is currently working on the Karuna House, a project which aims to get certified for three of the most important “green” standards – LEED, Passivhaus and Minergie-P-ECO.

Currently under construction in yamhill County, on a perch overlooking Willamette Valley,the Karuna House plans to “study to shed light on the ways that the leading green building certifications and standards complement one another, and the ways that they may conflict.” At least according to Hammer & Hand, who is building the home for a mystery client, who is “a leading proponent of smart climate policy and sound land use.”

Although construction is still in the early stages, the team working on this challenging project has already had to come up with a series of workarounds to keep it in compliance with all the three green standards. For example, Minergie-ECO prohibits site-applied spray foam, a material previously specified in the original plans, so the guys had to use high-density cellulose insulation and fill the gaps with acrylic-impregnated expanding foam tape. The Minenergie-ECO standard also doesn’t allow the use of treated lumber inside the building’s air barrier, so this was replaced with borate-treated sill plate installed over a structural EPDM gasket. Finally, code requires hood exhaust units in kitchens, which didn’t work well with Passivhaus and Minergie-P certifications, so the builders had to  locate the heat recovery ventilator near the kitchen and install a recirculating fan with a grease filter between the kitchen intake and the HRV.

So although, there hasn’t been any real building done on the Karuna House, Hammer & Hand has faced some serious challenges, but managed to abide by the rules of LEED, Passivhaus and Minergie-ECO standards, and avoided any conflicts. Still the team admitted there’s a big chance bigger problems will come up as the building process advances.

The revolutionary three-bedroom Karuna House will have 3,261 square feet of interior space, and will incorporate three foundation strategies: slab on grade, platform framing (decking above a slab), and a full basement. Expanded polystyrene under every element of the foundation will bring its R-value to 56, and the R-48 exterior walls will have 2×6 studs filled with cellulose and 6 inches of exterior polyisocyanurate foam. The roof will have an R value of 92, thanks to the 8 inches of EPS covering the sheathing and the 16-inch-deep I-joist rafters filled with cellulose.

We’ll be following the progress on the Karuna House and how the guys at Hammer & Hand manage the three certifications. I’m holding my fingers crossed, but obtaining LEED, Passivhaus and Minergie certifications will be pretty tough.

 

 

 

Green Building Advisor