The more informed the client, the better the outcome, especially if the project is a high-performance custom home. Clients naturally expect their builder to be up to speed on the latest sustainable methods and technologies, but the builder also expects the client to have more than a rudimentary knowledge of what’s available.

The projects depicted here were carried out by highly skilled, well-trained professionals for clients who take green issues seriously. The homes are a reflection of the owners’ values and of the dedication of the builders and designers. As architect Arielle Schechter says about the Happy Meadows project, “There were no restrictions except the ones we put on ourselves to walk softly and modestly on the land.”

Living off the grid with alternative technologies

A hybrid building system of straw bales and rammed-earth blocks forms the structure of a home that is completely independent of conventional energy sources. The house is sited on 170 acres along a creek in rural Sonoma County, Calif. Most of the property is steeply sloped. 

Many reclaimed and recycled materials were used, including the recycled glass countertops in the kitchen (Photo: Edward Caldwell).

“The site is far from the nearest power line, so one of the biggest concerns we had was solar access and solar gain,” says David Arkin of Arkin Tilt Architects, in Berkeley, Calif. Based on solar analysis, the architects sited the house on a south-sloping open hillside.  

The clients, who have twin daughters, wanted the house to be a reflection of themselves: natural and healthy. They had seen other homes designed by Arkin Tilt and liked the idea of using straw-bale construction to maximize energy conservation (see sidebar). 

Building with Straw

Bales and Rammed Earth

Arkin Tilt Architects, in Berkeley, Calif., and Earthtone Construction, in Sebastopol, Calif., were a perfect team for the residence in Sonoma County. Arkin Tilt specializes in energy- and resource-efficient design, while Earthtone focuses on sustainability, mindful building, and energy upgrades. 

This was the first time that Earthtone’s crew had worked with straw-bale construction and a post-and-beam system that uses I-joists as vertical posts. The bales fit between the posts. Substituting straw bales for lumber relieves the pressure to log old-growth forests and results in net-carbon sequestering, “which is critical as we face growing carbon-driven climate change,” says architect Anni Tilt, whose firm has built about three dozen straw-bale houses to date. 

Straw-bale construction is a proven, durable method, Tilt adds. If properly built and maintained, straw-bale homes can have a useful life span of at least 100 years.
Earthtone’s Andy Bannister says that getting the bales to fit “is pretty labor-intensive; there’s a fair amount of trimming and modification required. You start building a wall and find that you have to cut a bale, thread string through it, sew it, and tighten the string. And once the wall is up, there’s more trimming to make the wall flush.”

The straw-bale walls are coated inside and out with a lime plaster finish. Plaster skins add thermal mass and mediate diurnal temperature swings. When the bales are laid flat and stacked like bricks in a running-bond pattern, the wall is 27 inches thick and achieves an R-30 insulation level. 

Adds architect David Arkin, “[The walls] also have great acoustic properties. And you’re creating a carbon sink rather than a structure that requires a lot of steel.”

The retaining walls are made of Watershed Block rammed-earth blocks. According to manufacturer Watershed Materials, the blocks have 50 percent less cement and 65 percent less embodied energy compared with conventional concrete masonry. They’re made from locally sourced earth and recycled aggregates, formed into blocks that fuse soil particles and rock fragments together.

“The lower level, which was cut into the hillside, was all rammed-earth blocks,” Bannister says. “Straw bales placed on top of the blocks stayed dry.”

The home is designed as a series of east-west running pavilions, roughly paralleling the topography and stepping up the hill. Direct sunlight keeps the main living spaces warm during cooler months, while overhangs and exterior shade fins direct the summer sun away from windows during warmer months.

The dwelling is relatively small for a family of four (2,249 square feet under the roof, plus a 516-square-foot pool house), but it lives larger, says architect Anni Tilt: “The kitchen transparently links the pavilions with doors that open wide to a contoured terrace that connects the main house to the pool house.

The lower level of the two-story home contains the kitchen, dining room, living room, office, media room, and laundry room. Upstairs are the master suite and a large bedroom—divided by double pocket doors—for the two girls, who share a bathroom. 

The detached pool house includes a bedroom, a bathroom, a sauna, an art room, and a roof deck for stargazing on clear nights. It serves as guest quarters when the clients have overnight visitors. 

The living room has a living roof planted with sedum, a low-maintenance ground cover. The family has a large edible garden that includes insect and butterfly-attracting plants. 
Electricity is generated by solar photovoltaic panels, and propane is used for cooking and heating. Reclaimed and recycled materials can be found throughout the house, which is dual-plumbed for future graywater recycling. Drainage off the roof is funneled through rain chains that run to a drainage rill through the central terrace.

“One of the neatest things we did was use material that had been harvested from the site, rather than having it trucked 
in from another location,” says builder Andy Bannister of Earthtone Construction, in Sebastopol, Calif. “It was mostly Douglas fir and some oak, which we milled into beams, rafters, and ceiling materials.”

The wood stove is encased in rammed-earth block walls that serve as a heat sink. (Photo: Edward Caldwell)

Happy Life, Happy Wildlife

Like the California home, Happy Meadows, in Pittsboro, N.C., was built for a couple who wanted a modestly sized house that would express their dedication to the environment and health. “They were the most informed clients I’ve ever worked with as far as their knowledge of green issues,” says Chapel Hill, N.C., architect Arielle Schechter. ‘They wanted to limit as much as possible the use of PVC, whose manufacturing plants cause chloride and mercury pollution and are disproportionately located in low-income communities.” 

The couple have no children and are close to retirement. Having seen Schechter’s courtyard house designs, they decided they wanted one. Sited to take advantage of solar gain, the home has an understated entry from the north side, opening up to large windows, views, and light on the south. 

The home’s modern design mirrors architect Arielle Schechter’s other work. Prevailing breezes flow through the covered deck and screened porch into the courtyard, providing continuous fresh air. The home’s modern design mirrors architect Arielle Schechter’s other work. Prevailing breezes flow through the covered deck and screened porch into the courtyard, providing continuous fresh air. (Photo: Allen Weiss)

The floor plan is one level with an extra bedroom that has a full bath and space for a kitchenette so it can be converted into a caregiver’s suite in the future. The couple also wanted a sunny spot for gardens and growing kitchen herbs, which would be easy on the 5-acre, south-facing lot. The internal courtyard provides the “delight” factor and a special green spot that can be enjoyed privately, Schechter says. 

The home is under 2,500 square feet, yet it provides plenty of space for a great room, master suite, exercise room, office, guest room/future caregiver suite, large pantry, two full baths, two powder rooms, and a “mega mudroom” for storage and organizational tasks such as mail sorting and laundry. 

Happy Meadows was built to strict PHIUS (Passive House Institute U.S.) standards. It earned a National Green Building Standard Emerald rating and is awaiting LEED Gold certification. It’s also a U.S. Department of Energy Challenge Home.

“The home is net zero with the potential to go beyond into net positive,” Schechter says. “By adding a few more rooftop solar 
PV panels, the owners will be able to not only power the house but also a small electric vehicle.”

The walls are made from prefab insulated concrete panels, custom-built off site in two days to the architect’s specifications and assembled on site in another two days with the help of a crane.

“The precast concrete panels are great for providing a very low-maintenance wall assembly,” says Kevin Murphy, president and founder of Newphire Building, in Chapel Hill, N.C. “It’s 5,500 psi concrete, so it’s fire resistant, impervious to insects, and can stand up to extreme weather. Another benefit is that the walls go up quickly, which helps keep the project moving and allows the house to be dried in faster.”

Water capture was a major driver of the home’s design. “We were able to achieve almost 100 percent rooftop rainwater capture,” Schechter says. “The majority of the rainwater falling on the roof is directed to a 1,200-gallon underground cistern, but about 15 percent is channeled via a butterfly roof and scupper detail to a water garden and wildlife pool.” 

Murphy says that his biggest challenge was the additional time and cost of sourcing items such as VOC-scavenging gypsum board, recycled PVC pipe, and triple-pane European windows. The home also has a geothermal heating and cooling system. HERS raters give it a 
score of -1.

The clients insisted on having a wildlife habitat and frog pond from the very start, Schechter says: “It is specifically designed to provide water for the animals that inhabit Happy Meadows. Special attention was paid to providing a safe habitat for frogs, since their numbers have declined severely in the past few decades.” She reports that there are already thousands of tadpoles in the frog pond.

Last winter, which was especially cold, the homeowners were able to turn off the heat at night and the interior temperature never dipped below 59 degrees. Their power bill averaged $16 per month, “which means that although we didn’t hit net zero, we are very close,” Schechter says.