above, photovoltaic panels on the trellis tilt toward the sun during summer and winter. they shade the patio and provide more than a third of
household electrical power. Left, the house uses salvaged and sustainable materials throughout, such as the strawbale material highlighted
in this “truth window.”
l Passive and active solar house
designed by arkin tilt architects,
l 280 square feet ( 26 meters) of solar
hot water collectors provide water-
and radiant space-heating: $12,000
l solar electric system includes a
4.7-kilowatt roof-integrated Unisolar array and a 2.8-kw astroPower
trellis-mounted custom, seasonally
adjusted array: $49,000
l Passive design features include solar
orientation, sod roofs, daylighting,
a greenhouse, concrete slabs and
l salvaged materials like old airport
hangar trusses and recycled-glass
countertops used throughout
l construction completed in 2005
of insulated concrete forms (ICFs), which require 50 percent less concrete than conventional poured walls.
We specified that all concrete use fly ash to replace at least 25 percent of the portland cement. This has
the additional benefit of providing better electrical grounding in the otherwise nonconductive dry, sandy
soil. Interior concrete slabs are finished with ferrous sulfate stain and water-based sealers. Staining was
completed with the help of a number of friends, including the architects and their children.
The main level of the house has strawbale walls, finished inside and out with sprayed earth, using site
soil. Wood-frame exterior walls are constructed with wood certified by the Forest Stewardship Council (FSC)
or with wood salvaged from old trusses. All exterior sheathing is slats of stained fibercement board panels.
These weather well in the high-ultraviolet environment. They’re also fireproof, an important quality on
the edge of an alpine forest. The roofs are of 10-inch structural R- 45 insulated panels (SIPs). Salvaged fir
4-inch by 10-inch splines extend beyond the walls, supporting generous 4-foot overhangs that protect the
walls from the sun. The roof design eliminates eave vents, another good thing in this fire-prone area and
a feature now required under the new California fire code.
A great way to reduce indoor toxicity is to use old materials that have long since finished outgassing.
We made structural beams from old airport hangar trusses; ceilings from vinegar barrel staves; paneling
from the off-cuts of weathered beams; aluminum shade fins on the greenhouse from airplane wing flaps
and ailerons; maple floors from an old schoolhouse; custom light fixtures from mining screen (with pebbles
from the original purpose still lodged in place); and countertops from recycled glass (including old manganese glass turned purple by the desert sun). We used many salvaged doors; ore-cart wheels supporting
railroad track beams at the terrace trellis; and old glass panels placed as shingles to create the Trombe wall.
Each of these elements has a story of its own. Visitors pause, look and ask questions.
Builder Rick Walters of Sage Design/Build in Minden, Nev., told me he especially liked being able to
recycle 50-year-old hangar trusses from the California airport where he learned to fly gliders in the 1970s.
“A big problem with salvaging materials is bringing them from one climate for use in another,” says Rick.
“But because this old-growth wood had weathered in the Nevada desert, abandoned for more than 10
years, I was able to use a very stable material. We accommodated the shapes and sizes of wood to the house
design with the owner and architect.” By milling them on-site, Rick used the entire trusses with zero waste.
The 6x6-inch Douglas fir was shaved on four sides to provide weathered “barn wood” for the home’s entry,
while the “heart” was milled to provide vertical-grain interior trim. The lesser-grade wood was used for
framing. The horizontal component of the trusses became beams in the master bed and bath.
Interior paints and stains are low- or no-VOC (volatile organic compounds). We avoided using carpet
and hard-to-clean floor surfaces, along with vinyl and PVC. One of my favorite moments came when I
overheard the subcontractor who was installing one of the solid-surface countertops: “…strangest installation I’ve ever done. There were no toxic fumes. Even the glue they supply smells like wet dirt.” Non toxic
building materials are good, not just for the health of the building occupants, but also for the health of
the folks who have to work with the materials during installation.
I wanted a house that fit in with its surroundings, and I’ve got it. Bear, deer, rabbits and quail feel at
home on my green roofs. Raptors perch on the metal roof and songbirds use the breezeway for shelter
during wind events. Even the wildlife approve. r
Suzanne Johnson is a retired Intel executive, where she worked as an internet engineering manager. She now
describes herself as a solar idealist.