Sustainable Straw

A charming house displays eco-ingenuity

From one direction, Carolyn Roberts gazes upon Saguaro National Park. From another, she sees the Tucson Mountains. But when she glances right or left, she sees straw. Well, not straw, exactly, but hand-plastered clay covering straw bales, which comprise the innards of her lovely, northwest side home.

Make that lovely and sustainable. Warm and cozy, with a heat-harvesting sunroom and those exquisitely insulating walls of straw, this 880-square-foot house only cost about $50,000 to build and generates a measly $35 monthly in utility bills.

Of course, it was all by design. "I'd been looking at natural building for about eight years," says Roberts, an online-advertising coordinator for Tucson Newspapers Inc. "I've always been a do-it-yourself kind of person, and straw bale is a lot more user-friendly than trying to build an adobe house or something like that."

After living in New York, her first summer in Tucson had also highlighted the need for top-notch insulation. But there was a sanity bonus as well: Straw makes for a remarkably quiet home. "I had two teenaged boys," she laughs, "and one of them was in a rock band. When I was building the house, they'd camp out up in the loft, and I couldn't even hear them."

It just goes to show that sustainability is an awfully holistic notion. It's also one you can see up close at the Tucson Innovative Home Tour/Tucson Solar Tour 2008. Each year, this sprawling soiree highlights the best and brightest in energy efficiency, featuring 25 beautifully clever dwellings, along with a bevy of experts.

Highlights will include the Roberts home, and a new, upscale community that's part of the Rio Nuevo development, with its combination of New Urbanism and sustainability. There will also be a rammed-earth home by a top national builder, and an artistic desert retreat.

There's no doubt about the need to showcase these innovative building approaches. According to the Environmental Protection Agency, traditionally constructed buildings are responsible for nearly 40 percent of carbon dioxide emissions, 12 percent of water use and almost 70 percent of America's total energy consumption.

Those numbers grow even more critical as the current number of structures in this country--5 million commercial buildings and 76 million homes--is slated to climb by millions in the near future.

Paul Huddy has been organizing the home tour for several years, and he's seen a surge in sustainable building over that time. As one sign of this, he points to the increase in sales of photovoltaic, solar energy materials. "It's grown at over 40 percent per year for the past three or four years," he says. "Wouldn't every industry like to be able to say that."

He also believes the trend is here to stay, counting it among the great epochs of civilization such as the Industrial Age and the Information Age. "The next one is going to be the 'Sustainability Age,'" he says, "because we are finally at the edge. We've pushed the old paradigms as far as we can go and we're in trouble. Our mission for this century is really sustainability."

It's a daunting challenge. But pioneers such as Carolyn Roberts demonstrate that sustainable building doesn't require a degree in engineering--and need not carry a hefty price tag. "Everything here is very low money," she says. "I built this home for financial reasons as well as environmental reasons."

For example, "I have no central heating, but just use the sunroom to heat the whole house. And I have a homemade solar water heater--just the guts of a water tank with a solar oven around it." The home "is cooled only with an evaporative cooler, but it does a fine job because the house holds its temperature so well."

Still, for all of these savings, she hardly dispenses with aesthetics. Consider the lovely earthen floor, the spiral staircase, the finely appointed rooms and the colored clay walls, mixed and applied by hand. "All of these natural products are really beautiful on their own," Roberts says.

For those walls, she blended clay with colors from a pottery store, along with very fine silica sand, and a final coating concoction of Elmer's Glue and water. There was also a focus on finding as many previously used materials as possible. "I got almost all my windows and doors at recycle places," she says.

The ceiling is drywall, finished with reed fencing from Home Depot. Her house has a metal roof, with a radiant heat barrier--double-sided foil that reflects solar heat out through vents, and interior temperatures back down into the house. "There's no reason to have really well-insulated walls," Roberts says, "unless you insulate your ceiling, too."

She has a passive solar design, meaning that the home is situated to get its heat from the south. And the home has a very narrow west wall with only small windows. "So the afternoon sun doesn't have a lot of access to the house," she says. "And the porch all the way around the house actually shades the walls, so that the sun isn't directly on them. I think that helps a lot."

The metal roof collects clean, potable rainwater--up to 500 gallons in a half-inch rain. "The two types of roof that will give you clean water are either metal or tile," she says. "Tile was just way too heavy and expensive for this kind of house, though. Instead, I just got basic metal and it worked fine."

Building this home was a labor of love. But labor it was: Starting in 1999, Roberts undertook the lion's share of work herself, with extensive guidance from noted straw bale consultant Jon Ruez. She lived in a trailer on her two-acre property, plugging away at the house in the evenings and weekends. A year and a half later, she moved in.

Today, Roberts loves her cozy, low-cost home. And she likes what it's made of as well. Which is to say, an abundance of natural materials. "I liked the idea that it could go back into the land without much pollution, and the idea of a house that was mostly chemical free," she says.

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