| October 4, 2007
Washington’s first home built outside of Seattle under the national Leadership in Energy and Environmental Design (LEED) Green Building Rating System is underway in Washougal’s Crown Point Estates.
The 2,500-square-foot, three bedroom, 2.5 bath structure is a prototype home being built by Renaissance Homes, a leader in “green” building practices in the Portland/Vancouver area, to test the economic and energy-saving practicality of a number of green building techniques, according to Randy Sebastian, Renaissance president.
“In order to get real world experience with these systems, we chose to do this in a home which is typical of those we build, not some special demonstration project ” Sebastian said.
Last year, Sebastian, whose firm is headquartered in Lake Oswego, hired Karl Lange to be the area’s first full time manager of building science to oversee and improve the firm’s Living Green sustainability programs.
The Washougal environmental system prototype residence is an ambitious effort by Renaissance to test the economic viability of a number of new and improved systems. There are several levels of LEED housing, depending on the systems used, and Renaissance is aiming for a Silver level designation.
Starting at the bottom, Lange said he’s keeping all storm water on site. The front driveway channels rain into a rain garden, planted with native species, in front of the house. Water percolates into the ground, which has been specially prepared with layers of soil, rock and aggregate. A similar system is behind the house.
Concrete foundations contain fly ash, a post manufacturing material from coal plants. This cuts the use of Portland Cement by 30 percent. In addition, all aggregate is from a local source.
Framing lumber comes from the Warm Springs mill which cuts from Forest Stewardship Council certified sustainable forests and windows are .3 R value, an even higher value than the .35 R-value window rating Renaissance currently uses. All Renaissance homes comply with Earth Advantage and Energy Star standards.
Rubber seals on all exterior wall penetrations are a requirement of the Rain Screen system which Renaissance uses on all its homes. Only Renaissance features Rain Screen in all new homes in this region. Rain Screen will have a new wrinkle in the prototype home, however, with corrugated polypropylene replacing the wooden batts normally used.
Developed in Canada, Rain Screen is an exterior wall system that eliminates the threat of mold by a 3/8-inch furring out of the siding to allow a channel of air circulation between the siding and the house wrap. This circulates air throughout the exterior of the house so it can “breathe” better. Any moisture which invades the space also runs through rather than seeping behind house wrap or house sheathing and causing rot or mold.
Polypropylene Rain Screen Batts being used by Lange in Washougal allow air to travel horizontally as well as vertically, an idea which he believes will make the system even more efficient.
In an attempt to reduce the amount of lumber in the home, it was specially engineered for 24-inch center framing, rather than the usual 16-inch. “Because we had special sheer and load engineering, we were able to use about 13 percent fewer board feet of lumber in the framing on this house,” said Lange.
Open web floor joists added to the cost of this house, said Lange. However, this makes it easier to run plumbing, electrical and HVAC ducts. “We wanted to see if the labor saved in these areas makes up to for additional material cost of the joist system.”
This also means that water pipes and air ducts are run through the second story flooring, instead of the crawl space below the main floor. Air ducts, already wrapped in insulation, will get a cocoon of spray insulation so they’re considered to be in the “conditioned” space (space that’s heated and cooled) for LEED rating purposes.
Other touches include a 95 percent efficiency furnace with variable speed fan which runs as needed and can account for a five percent saving in energy. The spray-insulated second floor mechanical room also has a tankless water heater and a special heat recovery ventilation unit that allows heat from warm and stale outgoing air to transfer to cooler incoming air. “We already have the heated air, so let’s not waste it,” said Lange.
Warm air registers and air returns in each bedroom encourage a more efficient airflow throughout the home because bedroom doors often are closed. A manifold system creates efficient distribution of hot water with a single pipe running to the center of the house and manifolds going to each appliance location from there.
“This uses less pipe, thus wasting less energy and water. It gives you the hot water piped directly to where you want it, rather than having it circulating all around the outer walls of the house,” he said.
As with all Renaissance homes, the Washougal prototype house has compact florescent lighting throughout and highly efficient spray insulation in all outer walls, a requirement to get higher LEED or Earth Advantage ratings.
“This will be an exceptionally tight home. It is an ambitious project for us, but I think we’ll be able to improve our Living Green program by measuring the results. We’re seeking the best of all worlds, systems that are cost effective from both home owner and builder perspectives,” said Sebastian.
This is only the third effort to build to LEED standards in Washington, while Oregon has a number of homes carrying a LEED designation, and Sebastian speculated that the lack of tax incentives in Washington could be discouraging builders and homeowners from constructing homes with more energy efficient and environmentally beneficial systems.
Renaissance Homes is one of the area’s largest builders with neighborhoods underway in Southwest Portland, Forest Grove, Beaverton, Wilsonville, West Linn, on the OGA golf course at Tukwila, several in Vancouver and Camas and in Bend.
The LEED Green Building Rating System™ is the nationally accepted benchmark for the design, construction, and operation of high performance green buildings. LEED gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings’ performance.
LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality.
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Renaissance Homes
16771 Boones Ferry Road
Lake Oswego, Oregon 97035
Voice: 503-636-5600
Fax: 503-635-8400
Emergency Service: 503-496-0711 or 866-567-6225
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