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gProjects, 5-Star Single-Family Homes

Marpac Construction LLC
Vital Stats
Location: Seattle
Star Level: 5-Star
Checklist: Single-Family New Construction Checklist (2011 version)
Verifier: Tom Balderston, Balderston Associates
SectionPoints
Site and Water146
Energy Efficiency117
Indoor Air Quality124
Material Efficiency69
House Size Multiplier1.1
Total Score501.6

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416 19th Ave E is a five-unit townhouse development located in the heart of Capitol Hill in Seattle. Designed by B9 Architects and built by gProjects, the townhomes are a demonstration of advanced energy performance and high indoor air quality in an elegant infill design that takes advantage of the small park to the south and their location in the 19th Avenue village.

These townhomes also demonstrate dramatic reductions in water use by collecting rain water for flushing toilets and outdoor watering, with excellent use of both pervious and recycled materials on the exterior. There is an impressive green wall on the street front - one of the first of this size on a townhome project in Seattle.

ENERGY USE

The project shows how a well-insulated home can make use of affordable systems to achieve the 5-star level and 30% energy savings. The energy performance stems from several relatively low cost upgrades:

  • Wall insulation is upgraded to R 28 using a hybrid "flash & batt" foam system
  • Windows are upgraded to triple pane, while keeping the protective trees to the south allowed large glass areas without overheating in the summer.
  • Very high efficiency gas water heating (Navien 95% tankless water heater) provides both radiant floor heating and domestic hot water
  • Low flow devices on sink and shower fixtures
  • Appliances are particularly low energy, including a Fagor 24" euro-style refrigerator and Bosch Ecosense Dishwasher

LOW IMPACT DEVELOPMENT AND RAINWATER CATCHMENT

The site is a narrow lot between an existing apartment building to the north and a wooded section of the park to the south. The design fits four attached and one detached home into this tight location along with entry courtyards and walks on the private park boundary. The homes look into a line of large deciduous trees that will help keep them cool in the summer and provide a beautiful vista from the large front windows.

The builder made extensive use of recycled materials in the landscaping, including recycled brick paving and reused concrete chunks carefully built into steps and walls. All of the paving is pervious, and the roof drainage leads into rainwater cisterns. The gathered water is filtered at several locations and pumped to the dwelling units for washing laundry and flushing toilets. The water is also used to meet a significant portion of the irrigation demand for the site. If the tanks empty out during the year, an automatic control switches to city water until the tanks are filled up again. To further reduce water use, all toilets are dual flush 1.28 gallon maximum models, along with low flow sink and shower fixtures.

The street facing side of the project includes a large "living wall" system that extends up three levels and is planted with Kiwi fruit. As of this writing, it is growing in well!

INDOOR AIR QUALITY and MOISTURE PROTECTION

The townhomes emphasize simple interior finishes with low toxicity and good ventilation for fresh air. The spray foam insulation near the outer surface of the walls and roof helps provide a more airtight shell. There are no carpets, which reduces the buildup of indoor pollutants and makes the home easier to clean. Whole house ventilation from a central Broan or Panasonic exhaust fan ensures fresh air intake, and all fans were tested for proper function and flow by the third-party verifier.

The exterior siding is installed over a ¾ inch rain screen space with a WeatherSmart breathable house wrap from Fortifiber. Window and door flashing details were checked on site for complete seals and physical drainage planes to ensure a very long lasting wall system. The roof is sealed with a heat welded TPO membrane.

MATERIALS WITH REDUCED ENVIRONMENTAL IMPACT

The materials used by gProjects demonstrate a strong commitment to low toxic and recycled content products. All kitchen counters are Ecotop, a mix of recycled paper and resins. Interior, caulks, glues and stains are checked for low VOC content, and all paints are Zero VOC rated. The MDF trim and cabinet materials have No Added Urea Formaldehyde (NAUF), and use a whey-based finish from Vermont Coatings. gProjects is one of few builders currently that create well-built exterior steps and walls with recycled concrete. The outcome not only looks good, but helps demonstrate how to reduce the high environmental impact of new (non-recycled) concrete. gProjects also makes fly ash or blast furnace slag a standard in its concrete mixes.

gProjects continues to demonstrate its environmental and social commitments with its high performance, beautiful, and comfortable homes that take it to the next level in multiple ways. And here's to tasty kiwis!

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Use pervious surfaces to reduce rainwater runoff