Construction photos courtesy Hammer and Hand
After extensive research (I googled it) I found that “Karuna,” as in the ultra-green Karuna House currently under construction in Yamhill County Ore., is Sanskrit for “compassion.” One website stated that Karuna translates as “any action taken to diminish the suffering of others.”
How does a house “diminish the suffering of others?” Good question.
Karuna House is designed by Holst Architecture, Portland, to meet some of the toughest environmental standards in the world. Along with shooting for LEED Platinum, the owner is also going for Passivhaus and Minergie-P-ECO certification.
No surprise, the owner, who is using the project as a case study in green construction, is a “leading proponent of smart climate policy and sound land use,” according to GreenBuildingAdvisor.com.
So the point could be made that by demonstrating how to contribute as little as possible to environmental burdens, the house will, at least eventually, “diminish the suffering of others” since an overburdened environment makes us all suffer, at least a little.
Energy efficiency is central to any green certification. Karuna House is covering that bet with PROSOCO’s R-GUARD FastFlash air and waterproof barrier system, installed by builders Hammer & Hand, Portland.
FastFlash is a fluid-applied, instantly waterproof, vapor-permeable system for stopping the unintended passage of air and water through the building envelope. Expensively conditioned air, leaking through seams, joints, pinholes, electrical and plumbing penetrations and other openings in walls can boost energy costs as much as if someone left a door or window open — perpetually!
That kind of waste — typical in many buildings — is a no-no for a building that must meet the world’s most stringent air tightness standards.
The FastFlash system has some other characteristics that came in handy for the Karuna House project, according to Hammer and Hand project manager Skylar Swinford. Among them are FastFlash’s ability to go on damp surfaces, and its vapor-permeability, which lets those damp surfaces dry out, even after being coated with FastFlash products.
Nothing else will do that.
Skylar explained that Oregon’s rainy Spring climate kept the job site saturated while Karuna House’s plywood structural walls went up. By May, there was enough structural framing up to “tent,” so that work could proceed despite the weather.
Even with the tent up, the plywood was still soaked. With any other exterior air and water barrier there would have been delays while waiting for the walls to dry. Installing a vapor-impermeable peel and stick on wet wood throttles the wood’s drying potential and would have slowed the construction process and added cost for mechanical dehumidification,” Skylar said.
Since the house can afford no air leaks period, Hammer and Hand installed the FastFlash system everywhere — even in places it doesn’t usually go, like the roof, and over parapet walls.
“We didn’t want to take any chances with the air-tightness of the building enclosure,” Sklyar said.
Though Karuna House is a residence, its design includes features found in commercial buildings, such as cantilevered decks, parapet walls and structural steel. There are also plenty of corners, turns, intersections, seams and joints — complexity which would turn peel and stick or fabric wrap installation into a nightmare, even if the walls had a chance to dry out, Skylar said.
In fact, he said, the air barrier installation went faster than planned and took less manpower than expected, even though they installed FastFlash in more places than usual.
The extra effort paid off as a preliminary blower-door test in June demonstrated the house’s air-tightness at 99.9 percent — even though the applicators were still spot-sealing the house’s 14,000 square feet of air barrier surface.
“We pressurized the house to 200 Pascals (about a 40-mile per hour wind load) and filled it with fog from a theatrical fog machine,” Skylar said. “Then we watched to see where the fog escaped the house.”
“There were only two places where we had leaks in the structural sheathing. Both were in areas we had not finished the FastFlash application. Since we hadn’t finished sealing, I was surprised,” he said. “Considering the complexity of the structure, I didn’t think the house would pass the air-tightness test on our first attempt.”
Because Karuna House will be leak-proof and heavily insulated, a little heating and cooling energy will go a long way. That’s less demand on the earth’s resources, as well as less stress on the checkbook.
Now we’re talking compassion.
Here’s Hammer and Hand’s outstanding video on achieving an air- and water-tight building enclosure.
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