Case Study

Vital Stats Location: Seattle, Capitol Hill Star Level: 5-Star Checklist: Single Family / Townhomes Average Square Feet: 2,049 Section Points Site and Water 130 Energy Efficiency 145 Indoor Air Quality 94 Material Efficiency 140 House Size Multiplier 1.00 Home Total Score 509

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gProjects LLC
Project: Urban Canyon

This month’s featured project is the Urban Canyon townhomes in the Capitol Hill neighborhood of Seattle. This 7 townhome project was developed and built by gProjects LLC, and was in the first round of recipients of the Built Green® Incentive. The Built Green Incentive was established to encourage builders to certify at the 4 and 5-Star levels of the program by helping offset the cost of certifying and designing innovative green projects. gProjects LLC received an incentive for this project based on innovative water savings features and low impact development techniques, as well as for the energy design. The project features a 100 percent pervious site outside of the building footprint, a vegetated roof, a vegetable garden and a greywater system that supplies water to all of the toilets. Photovoltaics were installed on three units, as well as a communal system on the community bike shed. The REM modeling shows the buildings will perform 30 to 40 percent better than 2004 International Energy Code and the tight envelopes will allow leakage of only 0.215 to 0.25 air changes per hour. Beyond the technical aspects of the project, gProjects paid great attention to the overall site layout and achieved high quality community design. By limiting parking to the exterior areas of the site and through detailed planning, the project has provided for several communal areas, including a pea patch, “the canyon”, and a shared bike shed. The Urban Canyon is a shining example of innovative townhome design and advanced green building techniques that incorporates a sense of community, the combination of which results in a truly integrated green project. To see a more complete inventory on the strategies utilized in the project, please see below.

Some of the many green features of the project include:

Site and Water Protection

• Site is 100 percent pervious excluding home footprints
• Drought tolerant and native landscaping used exclusively, no lawns
• Use of dual flush toilets in all units
• Used greywater for toilet flushing
• Extensive provision of community spaces and walkways
• Provision of rain barrels
• Used no garages
• Community garden
• Installed a vegetated roof system over a community structure on-site

Energy-Efficiency

• Homes estimated to perform 32 to 45 percent better than 2004 International Energy Code
• 1.2 kW photovoltaic system on unit 3, 1.4 kW photovoltaic system on unit 2 and a 2.9 kW photovoltaic system on unit 7
• Installed a 1.4kW communal photovoltaic system on the community bike shed
• Blower door test results range between 0.215 and 0.25 ACH
• Installation of hydronic heating systems with a 92 to 97 percent AFUE efficiency rated boiler
• Installed heating systems with separate zones and controls

Indoor Air Quality

• Installed formaldehyde free or GREENGUARD certified insulation
• No carpets used in homes
• No garages
• Used low toxic adhesives and sealers extensively
• Installed all shelving, molding, and trim that contained no added urea-formaldehyde
• Installed whole house radiant heating system, no forced air
• Installed a rain screen siding system with a drainage plain between house wrap and siding

Material Use

• Performed deconstruction on the existing homes on site and re-used salvaged goods in the new project
• Used advanced system framing for the project
• Achieved a recycling rate of over 90 percent by weight for the project
• Used salvaged materials for flooring and siding
• Installed hard surface tile with 40 percent recycled content
• Installed a 50-year siding product and 30-year rated roofs
• No use of pressure treated lumber
• Framing with finger jointed studs

Still Images

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Photos by Vista Estate Imaging.

 

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