Common Ground; An Uncommon Energy-Efficient Community

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Common Ground community on Lopez Island, Washington, rallied their resources to build small, efficient, solar-powered straw-bale homes.
Common Ground kids at play.
Built in 2008, the Common Ground community on Lopez Island, Washington, is a showcase of energy efficiency and social collaboration to provide an oasis from rising housing costs.
The 11 energy-efficient homes use both active and passive solar energy strategies.
Inside, natural, nontoxic finishes help ensure good indoor air quality.
Thick straw-bale walls offer good insulative value. The earthen plaster walls and concrete floors provide thermal mass.
Evacuated-tube solar water heating systems offset up to 75% of each household’s domestic hot water.
The solar water heating system includes an 80-gallon SuperStor tank with built-in heat exchanger and a FlowCon FA glycol pump station. The glycol is heated by rooftop-mounted Thermomax evacuated-tube collectors.
The utility didn’t allow LCLT to install one large community array. Instead, 11 individual 3 kW grid-tied systems were installed, one for each home. This cost more but also triggered a larger subsidy.
The utility didn’t allow LCLT to install one large community array. Instead, 11 individual 3 kW grid-tied systems were installed, one for each home. This cost more but also triggered a larger subsidy.
Wide-open solar exposure on the site’s southern boundary made a ground-mounted array preferable.
Community members and volunteers worked together to build the straw-bale homes.
Community members and volunteers worked together to build the straw-bale homes.
The straw-bale building process was perfect for an untrained volunteer workforce on a budget.
Cooperation and camaraderie during the building process made for an emotional investment in the community.
Rainbow lights up the community and PV array.
Choosing to live in community takes commitment, but the work is empowering and fruitful.

In 2006, a group of local residents set a goal of creating net-zero-energy (NZE) straw-bale homes as part of the Lopez Community Land Trust (LCLT), an affordable housing project on Lopez Island in rainy Washington State. By 2007, we had architectural drawings and engineering designs. In 2008, we became a part of the resident-builder construction process of 11 homes, and have lived in one of these cozy homes since their completion in March 2009.

Project Origins & Objectives

In 1989, home prices on the island rose 189%. Locals found it increasingly difficult to find affordable housing. A group of Lopezians came up with the idea of a community land trust (CLT) housing development as a possible solution. In a CLT, land is held in trust by a nonprofit organization and removed from the speculative real-estate market for perpetuity. The homes are owned by individuals through cooperatives. LCLT homes are allowed to increase their value only 3% (noncompounding interest) per year, thus ensuring permanently affordable housing. There are roughly 250 land trusts in the United States.

By 1992, LCLT had finished seven homes in Morgantown, the first affordable housing project in Washington State. The homes were built with resident sweat equity, working with volunteers, LCLT interns, and contractors. After Morgantown, the LCLT completed Coho (seven homes, 1995); Innisfree (eight homes, 2003); Common Ground (11 homes, 2009); Tierra Verde (four homes, 2012); Salish Way (three homes, 2015); and is working on three additional homes.

Many who turned to the LCLT for housing did not qualify for traditional mortgages, which usually require excellent credit history and reliable, consistent income history. LCLT negotiated a group mortgage on behalf of the homeowners who formed the cooperative. The cooperative makes mortgage payments to the bank, and each co-op member pays their share of the mortgage to the co-op. Ownership of one share in the cooperative entitles the shareholder to reside in one of the homes. If a share­holder is unable to pay, the co-op tries to work with the shareholder to address the payment issue, taking into account the shareholder’s circumstances. A backstop for the first few months of delinquency is to deduct the monthly assessments from the shareholder’s equity. Continued nonpayment can be grounds for being asked to leave the cooperative. In that event, the share is sold at full value, but the shareholder receives a reduced amount, reflecting the amount withheld by the co-op for nonpayment.

Pioneering Affordable Homes

Inspired by a speech by William McDonough, the author of Cradle to Cradle, a manifesto calling for transformation of human industry through low-waste and ecological design, LCLT members focused on developing an NZE neighborhood called Common Ground, with a project concept of superinsulated, passive solar, solar-powered, straw-bale homes, with water catchment and permaculture landscaping.

LCLT contracted with solar installer Dana Brandt of Ecotech Energy Systems to further evaluate the NZE concept. Ecotech used recorded data from the three existing LCLT communities of 22 homes and information from existing NZE home projects to estimate the energy requirements for Common Ground homes. Seattle-based architectural firm Mith¯un was selected to guide the homes’ design. The designs evolved as LCLT and Mith¯un made revisions based on available budget, skills, and timeline. The final design called for 11 homes in three different sizes: 740, 864, and 1,160 square feet.

Building Efficiency First

Solar siting and an efficient envelope. With excellent solar exposure from horizon-to-horizon, the homes are oriented with east-west lengths and substantial south-facing glazing for maximum solar gain in the winter. A high south-facing clerestory with operable windows assists with passive, stack-driven ventilation. The floor of each house is a 4-inch concrete slab above a 2-inch layer of R-10 rigid foam insulation. This provides thermal mass for absorbing daytime solar gain. When inside temperatures start to fall, this stored heat is released to heat the space. Several layers of earthen (interior) and lime plaster (exterior) finish over the straw bales provide additional thermal storage.

The north, east, and west walls are nonload-bearing straw bale (timber-frame structure) providing R-34 to R-42—double the level required by local code. The south walls are 2-by-6 studs, with blown in cellulose for R-21. A cathedral ceiling above the kitchen and living room is insulated with spray foam for R-50. All other rooms have a dropped ceiling insulated with 14 inches of blown-in cellulose, also R-50. All windows are argon-filled, low-e coated, and double-pane. Windows on the south, west, and east walls have a 0.31 U-factor, an SHGC of 0.61, and a VT rating of 0.63 with double glazing and insulated spacers to maximize solar insolation. The windows on the north walls have a 0.27 U-factor, an SHGC of 0.28, and a VT rating of 0.49 with double glazing and insulated spacers to maximize heat retention.

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Comments (1)

Mick Sagrillo's picture

Hey Chris Greacen (and Chom), good to see you are still out there doing good work! Take care, Mick Sagrillo

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