Extreme Building

The Villas at Mia Tia Circle - a learning lab for a better way of building.

By John O'Reilly, Contributing Editor | September 30, 2001

Steve Bauman makes no pretense: He’s not really a home builder. At least it’s not his first choice. Then again, the way he sees it, until recently he hasn’t had much of a choice. “I am a builder by default,” he says. “I’ve done building throughout my career because people didn’t quite understand the things I would design. It was easier to build it myself than to try to bring another contractor in.”

Bauman considers himself “more landscape architect than architect, although I am foremost an environmental scientist.” A native of the Finger Lakes region in upstate New York, he has bachelor’s degrees in all three disciplines from Syracuse University, from which he graduated in the early 1970s. Working in these three fields during the past two decades, Bauman has acquired deeply felt convictions on the art and science of home building and its indispensable role in enhancing the physical and psychological welfare of the people it serves.

Bauman acknowledges that his chosen disciplines are occasionally at odds with one another on the job site. “The architect believes anything is possible thanks to technology,” he says. “Technology allows him to impose his vision and exert full control over a site. The landscape architect, on the other hand, tends to work with what’s already there, with a goal of creating a mutually beneficial, organic fit between what’s man-made and its natural surroundings.”

And the environmental scientist? “He looks at all the unseen chemical reactions happening inside and outside the home,” Bauman explains. “Are the building materials used to construct the home making its inhabitants sick? Is the building constructed so tightly that fresh air cannot penetrate to kill toxins or push out the particulates and the volatile organic compounds (VOCs)? Is the fertilizer in the lawn ending up downstream in someone’s drinking water?”

These and similar questions have led Bauman and his Austin, Texas-based company, The Millennia Group LLC, to espouse building materials and practices that are — as he puts it, with a mixture of pride and resignation — “sort of out on the fringe.” Bauman’s values and methods are displayed in the form of a “smart growth model green community” in Austin: The Villas at Mia Tia Circle.

Situated on a half-acre site, the development consists of four stand-alone, single-family condominiums, spanning from 1,600 to 2,380 square feet. The site is owned by the condo association, while the villas are privately held. Selling prices ranged from $169,000 to $290,000, although those figures date back to 1999, when Bauman sold the villas just before breaking ground on the project. “If you put them on the market today,” he estimates, “they would probably go for $225 per square foot.” Each villa — named Woodlands, Rockridge North, Rockridge South and Thorncliffe — is done in a different architectural style and features different building materials, but always to the same end: to demonstrate the principles of sustainability and energy efficiency, low maintenance, and maximum health for the inhabitants.

The Mia Tia Circle project was conceived first as an educational venture and only secondarily as a residential development. While all four villas are sold and one has been occupied since October 2000, Woodlands and Rockridge South will remain open to visitors through February 2002. The city of Austin’s Green Builder Program, The Millennia Group and various manufacturers that underwrote materials used on the project will periodically host open houses and other special events during this public viewing period. A directory catalog — describing a history of the project as well as the companies and products involved — will be available in print format and via CD-ROM. This information will also be delivered on the project’s Web site.

Uphill Battle

For Bauman, Mia Tia Circle is nothing less than the culmination of his working career to date. He estimates the total in-the-ground investment at $1.3 million, including his and wife Ann’s personal fortunes. “We had a heck of a time getting this project financed,” he says. “I went through 40 institutions, many of whom were worried about the marketability of alternative materials and our emphasis on the environment. I finally found two banks willing to embrace the concept. But one was acquired, so I’m now down to one.”

The city of Austin also had issues, even while serving as a partner on the project through its Green Builder Program, an offshoot of Austin Energy. Bauman originally came to town from North Carolina in the mid-1990s, attracted by Austin’s fast-growing reputation as a haven for alternative ideas in home building. “I met with people in the Green Builder Program,” he recalls of his first trip there, “and they spoke the same language as I did. Back in Carolina, at least at that time, I was always having to drag and push people toward the notion of environmental stewardship. On my first visit to Texas, I immediately picked up two clients who wanted me to design green homes for them — blew my socks off!”

But once he became immersed in the Villas at Mia Tia Circle, Bauman had to present his ideas to local code bodies and officials, who not surprisingly had a less visionary slant on what he was attempting — a slant that is codified, to the letter, in the regulations.

“It was a very difficult process getting code officials to feel comfortable with unfamiliar materials and practices,” Bauman says. “Even if what you’re doing is better, because it’s different, it raises numerous questions. But we stuck with it by hiring several independent engineers to testify on behalf of the materials we wanted to use and their standards.”

Builders proved even more skeptical than bankers and code officials. Bauman initially saw his role as strictly that of developer — as well as, of course, architect, landscape architect and environmental scientist. So as he readied the site for construction two years ago, he offered each of the four villa plans to a half dozen local builders but found no takers. Part of the problem was that, in 1999, Austin’s residential market was so vibrant that no builder had to scramble for work. Asked to try something foreign to their way of working, involving materials not only different but often more expensive, the builders Bauman approached inevitably responded with a resounding “Thanks, but no thanks.”

“Any time you try something new, it takes time to master it,” Bauman says, “If your crew needs three or four times as long to figure out the new way, that’s three or four times the cost. When you are totally preoccupied with this year’s or even this quarter’s bottom line, you’re probably going to stick with what you know best.”

Which is why Bauman took it upon himself to prove that his ideas deserve mainstream attention.

Field of Debris

What exactly are these ideas that so many found difficult to embrace? The best place to start is with Mia Tia Circle itself. A moonscape terrain kept it undeveloped for 30 years. Roughly square in shape, this little patch of land is located amid an up-to-date, suburban community in the North Hills section of Austin, surrounded by homes, schools, retail and recreational facilities.

The half-acre lot sits on the edge of what had been a granite quarry. When a nearby school was built in the late 1960s, 25 feet of quarry fill and construction debris from that site — including red-granite and limestone boulders the size of pickup trucks — were pushed onto Mia Tia. What resulted is a steep hill rising roughly 18 feet from street level and twisting in an S-shaped curve around the site. The area is also thickly populated with 38 Spanish oak, chinaberry and cherry trees, most of them quite large.

The conventional approach to this type of site is to call for bulldozers. But the economics of scraping Mia Tia’s rugged, hilly terrain flat and smooth were so formidable, no conventional builder tackled the site.

“We decided to value-engineer the entire site,” Bauman explains. “We left not only 80% of the trees because of their shade value in this hot climate, but also all the quarry rubble, using it as a design feature — something to look at and appreciate.”

For someone who believes in preserving what nature and circumstance bequeathed, Mia Tia Circle presented a kind of ultimate challenge for Bauman and his design team. Of course, on pure principle alone, landscape architect Bauman would never opt to bulldoze any site flat. “Some builders scrape the land bare because it’s quick and easy. Later on, they plant some small and inexpensive trees. They basically disrupt all the vegetation in a place, which will need 20 to 30 years to be fully restored.”

Millennia defines its mission as “doing the best we can, with the least environmental impact, at a reasonable cost,” Bauman says. But he readily concedes that “value-engineering the vegetation” is typically more expensive in the short run. Indeed, Millennia’s comparatively surgical site work at Mia Tia Circle lasted eight months. These preservation efforts can also be a major nuisance and hobble productivity, especially if you care about the impact heavy equipment can have on surrounding trees. “Large machinery simply traversing a job site can compress the soil under a tree and damage the root system,” Bauman says. “Three years later, the tree is dead and no one knows why.”

Still, leaving the vegetation intact is worthwhile in the long run, Bauman insists. “The maturity of the greenery, particularly the larger trees, is what gives a neighborhood its premium value. Why wait 20 to 30 years for that value to grow along with the vegetation?”

Cool Water

Millennia found three relatively open pads at the top of the Mia Tia Circle site. There it located Woodlands and the two Rockridge units, which are connected by an expansive, deck-entry system made of recycled cedar chips. At the bottom of the hill sits Thorncliffe. Gazing up the hill from this villa, a visitor sees water cascading down the elevation through a network of three whirlpools of moderate depth and interconnected by waterfalls. The resulting aeration provides a natural form of air conditioning that with all the tree shade cools the site even when the mercury hits triple digits.

The pools are constructed of limestone and red-granite boulders removed from the basement of adjacent Rockridge South. “As we dug that villa’s foundation,” Bauman says, “we lifted the rocks with two large chains hooked to the end of an excavator, which swung them into position at each of the three pools.” The upper whirlpool contains goldfish, while the middle pool a few feet lower is equipped with a seat, whirlpool jets to keep the water turbulent and a bank of fiber-optic lights to highlight the waterfall. The third pool at the bottom is home to turtles and various plants.

The water circulates from the pools through a pump house, where it moves through charcoal and particulate filters. Then it is treated — not with chemical additives, such as chlorine, that might prove harmful to residents or the surrounding vegetation — but with a patented combination of ultraviolet light and ozone. Moving 6,800 gallons of water per hour, the pumping system runs around the clock, using solar power whenever possible, with electric backup on overcast days and at night. “The water in the system is absolutely pristine,” Bauman says, “with absolutely no waste — in contrast to a reverse osmosis system that dumps roughly 8 gallons of water for every 1 gallon it purifies.”

Natural Wonders

The natural and man-made splendors of the waterworks system and the surrounding vegetation serve as the focal point of the Mia Tia Circle project and as the front yard for all four villas. Each home is deliberately oriented to point inward toward the trees, the pools and one another so that residents can observe the surrounding scenery from their front doors and exterior decks. The villas’ back yards are the streets of the surrounding subdivision.

As Bauman notes, four homes on a half-acre site cannot help but be close-knit. But any cramped feeling is mitigated by the site’s steep elevation, which engenders the illusion of greater space. Likewise, the many tall trees provide a sense of privacy, though not isolation. The net result is as if the villas were there first and the trees grew up around them.

“All the houses are situated on the site to enhance their views,” says Bauman, explaining how he approximated a sense of open space. “While the view of the house next door is typically through a smaller window, larger windows look out on the pools, the waterfalls, the trees and beyond.” For example, the third-story deck of Rockridge North, one of the site’s loftiest points, looks across a distant valley to the University of Texas campus miles away. Across the way at Woodlands, the den off the kitchen has the feel of a child’s treehouse, sitting 12 feet in the air and popping out of the main structure amid the branches of a large oak that pokes through the deck just outside the door.

But Bauman’s overarching goal was not simply to build four free-standing homes, each a small and beautiful world unto itself. Rather, he sought to create an intentional community, using both structural and landscape architecture to spur awareness, interaction and communication among the residents. This intent is reflected in the structure of the condominium association, which is charged with maintaining the trees and the waterworks system, as well as the deck that connects the two Rockridge villas. Individual owners are free to develop the landscape immediately surrounding their decks but with limitations. An owner may not use any but organic fertilizers on the lawn, nor may fencing be erected. To alter the color of a domicile, an owner must secure the approval of at least two of the three neighbors.

“The houses are secondary,” Bauman says. “The interaction is primary. By turning the units around to look at each other instead of the street, we have deliberately tried to create a sense of community. You get to know your neighbors and their routines, whether they are home or out of town. That’s vital to the quality of life in any development.”

Rainwater Harvesting

The Mia Tia site is zoned for nine to 11 residential units “depending on which ordinance you look at,” Bauman says. He never seriously considered that many units, wanting from the outset a low-density development. In addition, that many structures would have required bulldozing the site flat. But even had Bauman not felt so strongly about preserving the site’s topography, the city of Austin’s limitations on “impervious cover” would have limited the unit total.

Impervious cover refers to the amount of square footage that rainwater cannot penetrate; i.e., roofs, sidewalks, driveways, decks, etc. When all the calculations were in, Millennia was allowed to build on approximately 6,800 of the 20,000 square feet available. But Bauman had a plan that would send the percentage of impervious cover at Mia Tia Circle plummeting into single digits: harvest every drop of rainwater that hits the steel roofs of the four units, purify it through the whirlpool-and-falls pumping system, and then return it to the ground or deliver it as drinking water to the residents.

For example, Thorncliffe’s collected storm water replenishes the third whirlpool at the bottom of the site directly. Once that pool rises to a certain level, a sump pump moves the surplus water to one of a series of three underground tanks, from where it circulates through the pool-and-waterfall system for purification at the pump house. Besides moving through the pools, this water is also used to drip-irrigate the entire Mia Tia Circle site through a series of low-pressure, underground loops.

“We put the water below grade under the plants’ root zone at a rate of one-half inch per week, which is roughly equivalent to the average weekly rainfall in Austin,” Bauman says. He points out that the site uses only plants and grasses that are indigenous to the area and therefore accustomed to this low level of moisture.

Meanwhile, storm water collected from the Woodlands roof feeds the three underground tanks directly, while rainwater from the two Rockridge units goes to a storage system within each of those units. That water is purified for potable usage with the same UV-ozone technology described above.

The net result of this rainwater harvesting system is virtually zero runoff and therefore no negative impact downstream. It also shrank the amount of impervious cover to 8%. The rooftop collection system more than offset the four houses, while the overhang of the roofs even compensated for some of the driveways.

Despite the environmental benefits of his harvesting system, Bauman struggled for a year-and-a-half securing approval from the city of Austin. “This type of system hadn’t been done before locally,” he explains, “so they didn’t understand how we could move water underground rather than simply letting it run off the site like any other development.

“We believe in taking care of our own environment. By doing so, the residents reap the benefits of these beautiful pools and waterfalls, as well as better vegetation and clean, healthy water.” The larger community gains, too. “By keeping water on site, we do our part to replenish the Edwards Aquifer near San Antonio, which has been dropping due to the level of growth in Austin. The price of water in our area is exorbitant today, and it will only grow into the billions of dollars over the next 10 years.”

Fighting Disease

Inside the four villas, Bauman’s focus remained much the same: to fashion an interior that is not only comfortable and pleasing to the eye, but also safe for every inhabitant. Public Enemy No. 1 here are the toxins that invade a home through the materials with which it is built. This situation is worsened by the tight insulation envelopes nearly every new home is fitted with today. Thus does the laudable pursuit of energy conservation wreak havoc with a family’s respiratory systems, triggering headaches, rashes and allergic reactions.

In making his case for alternative building materials, Bauman notes oft-cited asthman statistics from the American Lung Association: a 72% increase among children and a 62% increase among adults in a single decade. “After the energy crisis in the late 1970s, people began to seal up their homes,” he says. “Each year the balloon gets tighter, and the rate of asthmatic problems in this country increases proportionately. Prior to that era, homes were open and fresh air came in, while stale air and chemicals were swept out the open windows and doors.”

To minimize toxic buildup indoors, Millennia chose to limit, if not avoid entirely, products containing formaldehyde, benzene or petroleum by-products. Thus, for wall, floor and roof insulation, Bauman rejected fiberglass in favor of structured insulated panels (SIPs) in all four villas. The latter are made of a urethane core sandwiched between two layers of OSB (oriented strand board). “This material is structural, lightweight, highly energy-efficient and, once manufactured, environmentally friendly,” Bauman says. “The OSB and the urethane adhere to one another with an epoxy resin rather than a formaldehyde-based glue, so there is very little off-gassing inside the home.”

Bauman used SIPs for the entire outer shell, including the roofs, of all four villas. This eliminated the need for an attic and the condensation problems such spaces can create in the warm, humid Texas climate. At Woodlands, for example, Millennia installed a high-efficiency air-conditioning system, with the equipment housed in a small room at the loft level, adjacent to the roof. In a traditional home, such a room could become a heat sink on hot summer days, with temperatures reaching as high as 200 degrees, Bauman says.

“Meanwhile, the rest of the house is 130 degrees or more cooler. If there is any leak, so that the hot attic air meets the cool air, condensation will form, followed by mold. SIPs enable us to put the entire system in a tempered space of around 70 degrees, minimizing the condensation problem while enabling the system not to work as hard: It’s fighting 75- or 80-degree air, not 200-degree air.” In addition, because all of the ductwork is within a tempered area, less insulation is needed as well.

Millennia used conventional materials in unconventional ways to minimize mold. Woodlands is built on a pier-and-beam system. Rather than building piers made only of concrete, whose porosity can hold mold when wet, Millennia constructed them of concrete and steel, encased in structural steel culvert pipe. “You get the finished look of steel, which also keeps the mold off the concrete.”

Haven of Health

One of the most striking features at Mia Tia Circle is the way Bauman maximized the amount of natural light entering the villas. Each villa is designed with a large open area from the first floor to the very top. (Remember, there are no attics.) Open trusses at the rooftop level allow multiple skylights to create “some wonderfully dramatic light-and-shadow patterns throughout the house,” Bauman says, “patterns whose shapes and colors change as the sun wheels around the sky.”

In addition, hallways are nowhere to be found, with one room opening on to the next. “At $225 per square foot, a 10-foot-long hallway becomes very expensive,” reasons Bauman, who also saw the design value in eliminating hallways. The result is an open, airy feeling that makes each house feel larger than its square-foot dimensions might indicate.

But this openness offers high utilitarian value as well. In Rockridge South, Millennia incorporated a cooling-tower design that uses thermal convection (hot air rising) to generate a natural, vertical airflow up through each structure. This cooling-tower effect was re-created in the three other villas by synchronizing the movements of operating skylights in the roof with windows down below.

As explained in the article on page xxx, the venturi-type airflow generated by the skylights helps cool the house to comfortable levels on all but the hottest summer days. At the same time, the air movement drives out stale air — and with it potentially harmful toxins — replacing it with fresh outdoor air comparatively rich in ozone. Thanks to television weather forecasters’ warnings about “ozone action days,” Americans are accustomed to thinking of ozone as something to be avoided. Bauman counters that ozone is our poorly misunderstood friend, without which humans could not survive.

“Where do people go to refresh themselves and their immune systems?” asks Bauman, to which he quickly replies: “the mountains and the seashore. Both places contain ozone in just the right concentration — 0.06 parts per million (ppm) — to kill bacteria, viruses, molds and mildew, while breaking down other harmful chemicals into water vapor, carbon dioxide, oxygen — gasses that humans can safely breathe.” Unfortunately, the typical new American home is wrapped so tightly — precisely to avoid the outside-inside air exchange Millennia looks to create — it has less than 0.01 ppm of ozone, according to Bauman. Systematically introducing ozone into his villas kills bacterial contaminants and breaks down any VOCs in the air.

Clear the Air

Bauman does not rely solely on the ventilating currents provided by the cooling tower. “We always install a duality of systems,” he says, referring to two devices he uses to achieve the same cleansing effects provided by the cooling tower.

Energy recovery ventilators: ERVs mechanically replace stale indoor air with fresh outdoor air. “Its operation is triggered by independent sensors that track the presence of chemicals in the air,” Bauman says. Through a desiccant wheel, the machine also modulates the temperature and humidity to more comfortable levels.

Air-purification systems: In addition to removing particulates from the air, these devices emit ozone at levels of 0.04 to 0.06 ppm to kill biologicals and VOCs. “Spray liquid cleaning ammonia on a paper towel and hold it in front of a purifier for 30 second,” says Bauman, explaining how the equipment works. “The paper towel will still be wet, but the ammonia will be gone, leaving water, oxygen and carbon dioxide in its wake.”

How does Millennia prevent all this fresh air from delivering unacceptable levels of dirt and dust inside the home? The purification system counters this problem by generating a low-impact, paid-pulse radio wave that constantly changes frequency from 250 to 400 megahertz “so it doesn’t harm human skin tissue,” assures Bauman. When an airborne dust particle encounters one of these waves, the former vibrates, taking on a positive or negative charge. A charged particle seeks out its opposite electric charge and forms a clump. “After a couple of them clump together,” Bauman says, “they get too heavy to stay airborne. The air-conditioning filter or the ERV filter will eventually trap and remove them.”

Bauman adds that the radio wave extends 60 feet in all directions, even penetrating the walls of the house. As a result, much of the dust and dirt falls to the ground before it even has a chance to enter through a window.

To Bauman’s way of thinking, you should not have to wait for a mountain or seaside vacation to enjoy the respiratory relief these natural environs provide. “The home should be an oasis away from the offices, stores, institutional facilities and other public spaces that we necessarily must occupy but whose environments are seldom good for our health,” he says. “Your immune system is battling with those problems all day long, so we want to eliminate that stress in the spaces we build. Once you arrive home, you should be able to rest and rebuild your body so it can return to the world stronger the next day.”