November 28, 2007
Here is what makes Cottage Home #1 a gold award finalist:
From the beginning, Pringle Creek and Bilyeu Homes went all-out. Beginning in the fall of 2006, the design team, led by James Meyer and Mark Kogut of Opsis Architecture, held weekly workshops with Pringle Creek’s select builders and the Oregon Department of Energy (ODE) to establish performance goals for the exterior envelope and work out constructability issues. This collaborative process helped the entire team to understand the architect and builder perspective while learning about the energy performance of different envelope systems for the home. The team vetted three roof systems, four high performing wall systems, and two foundation systems.
The roof systems explored were all non-venting. A decision to use a low-density foam was made because of a cost-benefit analysis that indicated the energy saved from the combination system was negligible to the first costs (first costs are the initial expenses of materials and labor as opposed to secondary costs for operations and maintenance, and tertiary costs for eventual replacement).
A 2x6 advanced frame wall system using FSC-certified lumber and plywood sheathing was selected. Using FSC products help protect our forests, streams and wildlife. The advanced framing system does many things at once. The exterior wall cavity is insulated with dense-pack blown cellulose (an environmentally-friendly product made up of recycled wood fiber). The exterior is sheathed, with all seams and penetrations taped forming a continuous radiant barrier around the perimeter of the home (saving lots of energy). The skin of the wall envelope is a vented rain-screen system that includes a layer of Tyvek house wrap (which allows moisture to drain behind and between the wall to prevent mold and potential dry rot). The foundation system selected was a short basement with the exterior wall insulated (to provide "conditioned" space that keeps a near-constant temperature, again requiring less heating and cooling demand).
The workshops stressed a best-practice approach to construction, including fully taped Tyvek house wrap; seams continuously taped; rigid insulation on the exterior wall; bottom plate caulked at subfloor; wall penetrations sealed with expandable spray foam; all wall and roof framing cavities filled with air-flow resistant insulations; walls with dense-pac blown cellulose; roofs with low-density liquid spray open cellular plastic foam that does not contain Urea Formaldehyde, CFCs or HCFCs. All of this is about durability, energy efficiency and healthy air quality. It is also the standard approach to every home built at Pringle Creek!
The driving force behind the design, which was led by Opsis Architecture, was to develop a home that would equal to the innovative features embodied within the planning and infrastructure of the larger 32-acre development. The result is a high performance home that is generating much of its own energy due to energy efficient design strategies, craftsmanship, and a scientific analysis of the systems.
The design includes a compact open floorplan; careful placement of operable windows; programmable thermostat; advanced framing; radiant barrier; detached garage; simple form; overhangs with trellis designed to filter light; materials sourced within 500 miles; energy analysis of the house envelope and the site; water to air geothermal heat pump; solar collectors; and rainwater harvesting.
The design addresses the specific climate and site conditions. The Willamette Valley has average winter min/max temperatures of 33/48 degrees; for summer it is 50/80. This is ideal for high performance homes using passive solar site strategies. The Cottage Home is oriented with the long axis running east to west. All windows in the cottage are high performance windows with glazing and are strategically oriented to maximize daylight and views to the neighborhood. Windows are located on two sides of the rooms in order to balance light and facilitate natural ventilation. The window area on the south side of the building is 25%, the north 12%. South facing overhangs feature a trellis, designed to maximize light in the winter and filter sun in the summer.
Landscaping at Cottage Home #1 utilizes drought tolerant native planting with a high efficiency drip irrigation system. A 1500 gallon underground rainwater harvesting system connects to the drip irrigation system. This reduces the impact of the irrigation needs and delays stormwater runoff entering the porous asphalt street system. Street trees were selected for their growth characteristics, in order to limit interference with active solar collection panels on the roof. The lawn for the Cottage Home comprises less than 10% of the available lot landscaped area, minimizing the need for irrigation and promoting social interaction with neighbors and the community at large (which has also instituted a community requirement for organic landscape maintenance).
During the construction process, third party testing (Earth Advantage, EnergyStar and LEED) acted as a guide and provided confirmation, via regular inspection, that energy efficiency goals were being met. A regular jobsite presence during construction also aided in streamlining this process.
Subcontractors with a high commitment to green building were enlisted to work on the project. The HVAC subcontractor, Lyons Heating and Cooling, insist that all of their crew remain involved in continuing education and certification, and each member of the crew is certified to conduct a duct-blaster test, allowing problems to be corrected immediately. Insulation was done in-house by Bilyeu Homes, via a spray cellulose machine to address the installation errors and product flaws of other systems and installers. This allowed full control over the finished product. Bilyeu Homes is dedicated to sustainable, healthier building practices. President Larry Bilyeu has long been interested in the environment and served as a member of the 2002-2004 Salem Environmental Commission.
