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A sustainable construction visionary tops his own home with a standing-seam metal roof that serves as an energy and water collector

Heron Hall Ma Jan18 3
Photo: Dan Banko

Jason F. McLennan is a leading voice of the sustainability movement and the founder of the Living Building Challenge. When it came time for him to build a home for his family, he wanted all the things homeowners want for their families, of course, but he also wanted to express very articulately his vision of a sustainable future. “I hope the house lasts a few centuries,” he says. “That doesn’t mean you’re not going to replace things… But you want the bones of the house, the structure, to live 200 hundred years like European homes were originally built.”

In addition to founding the Living Building Challenge, McLennan is designer and urban planner and founder of McLennan Design, located on Bainbridge Island, Wash but doing work internationally. His firm did the design work on Heron Hall, the name given to the house because of the prevalence of the bird in the area.

A Model Home

Heron Hall is a 3,300 square-foot house that sits on about one acre of land along a manmade estuary. In the distance, the family can see the ferries working the commuter route between Bremerton, Wash., and Seattle.

The house itself fulfills a design philosophy that McLennan calls “Salvage Modernism,” which combines salvaged building materials with a modern aesthetic. The result is striking and environmentally sound. Among the most unique salvaged materials are stained glass windows from a century old Seattle church and hand-carved doors from Afghanistan that had been brought to Seattle for another project.

While re-use of materials is important to improving life cycle footprints and reducing impact on landfills, modern building materials and techniques are essential to ensuring today’s homes meet the needs of contemporary families. Among the many sustainable materials McLennan selected for the house is a rammed-earth structure for the first story, sustainably grown wood cladding, and VOC-free paints.

To meet the Living Building Challenge, the family will document the energy and water performance of the house for the next year. The challenge is to use net zero energy and water.

Photo: Dan Banko

“We wanted to build something that was one of the greenest houses in the world and also show that sustainability can be really beautiful and functional. We tend to win people’s hearts over with something that inspires them.”

Jason F. McLennan, Living Building Challenge Founder

A Big Metal Energy and Water Collector

The metal roof, which runs over the two-story body of the house, was selected to help fulfill those energy and water requirements. “We try to use building materials in ways that are best suited for the materials properties,” McLennan says. “A roof takes the most abuse of any surface and it has to do a lot of things for you. Overhangs provide shading for windows for example. Its primary task is to keep rain and snow out of the home. It needs to be incredibly durable because it’s getting pounded by everything. Metal is the best material for roofing, with the possible exception of green roofs, and we have that as well. But the primary roof is metal.”

Solar panel installation. Photo: Josh Fisher

The structural standing seam roof from Metal Sales Manufacturing Corp., Louisville, Ky., uses 22-gauge roof panels. The ridge runs east to west, which provides a large southern exposure for a solar array. The eaves drop low enough to provide shading during summer months and allow winter sunlight to warm the house. The mass of the rammed earth structure absorbs the heat and radiates it out during winter.

 During summer, that same mass tends to keep the structure cool. The house has no air conditioning and does not need it. The solar array uses photovoltaics that provide electricity for the house and also power the family’s electric cars.

Clean Water Run-off

No building product is isolated. They are all part of a system, and the roof is a very important part of the rainwater system in the house. At Heron Hall, that is especially true since the roof is the main collector for the rainwater collection system that provides 100 percent of the family’s water. To be able to reuse that rainwater, the water shedding from the roof needs to be clean. “Because we also used the roof as a water collection surface,” McLennan says, “it needed to be inherently clean. That means no asphalt shingles, which are loaded with chemicals. And you can’t capture water off a green roof.”

McLennan specified Minneapolis-based Valspar Corp. Fluropon Pure metal coating. “The new Valspar coating,” McLennan says, “was the first coating for a metal roof that is on the DECLARE List of products under the Living Building Challenge.” That means the coating uses none of the chemicals that land on the dreaded Red List of chemicals damaging to the environment and human health, and that Valspar has been transparent about its manufacturing process so buyers can trust its sustainability claims.

Water running off the metal roof is collected in a 15,000 gallon cistern that nestles tightly to the house and fits the salvaged modern aesthetic, especially given the homes natural setting. All water for drinking and other uses comes from the collected rainwater. In fact, the home isn’t even on the municipal sewerage and uses composting toilets.

The McLennan family moved into the house in April 2017 and last month enjoyed its first holiday season.

Photo: Dan Banko