More Breathing Space

Indoor air quality (IAQ) was not priority No. 1 for Virginia Ranch Development project manager Davis Johnson as he oversaw construction of an 800-home community in Gardnerville, Nev., near Carson City. It seldom is. Like just about everybody else in the business right now, Johnson's biggest concern was lowering costs and bringing the project in on time.

Bent on efficiency at every turn, Johnson and Derwin Bass, the project's chief architect, came up with an engineering, design, and construction plan that would cut back on site excavation and result in less trucking of materials to and from worksites, less labor, less concrete, all in less time. It was an inadvertent bonus when the two men realized that, in their ferocious effort to save money, their plan would also achieve higher indoor air quality in each new home.

What Johnson and others discovered is that IAQ is getting faster traction among home builders in an assortment of shapes, sizes, and problem/resolution packages. For years now, home buyers have paid little more than lip-service to the notion of green building, healthy homes, and energy efficiency. Builders have been operating in a double bind. They know they can build more environmentally sound, higher performance homes, but they're reluctant to do so if they can not pass on the engineering, design, and materials cost premiums to home buyers.

But as sourcing, design, materials technologies advance in sophistication, home builders like Johnson and Bass are finding that high indoor air quality performance and optimal cost efficiency on 50 to 75 percent of the cost of goods sold for each house aren't by nature mutually exclusive.

BREATHE EASY: New building technologies improve ventilation, reducing indoor air quality problems.

In the case of Dayton, Nev.-based Virginia Ranch Development's Gardnerville project, on the eastern slope of the Sierra Nevadas, the solution led to a widely used sub-foundation system called Cupolex. Fact is, concrete slabs are known culprits for indoor air quality problems. In contact with the ground, moisture wicks through concrete and can contribute to the growth of mold and mildew. Radon gas and vapors from contaminated soils can also seep through the slabs.

Cupolex, created by Pontarolo Engineering, was developed in Europe 10 years ago specifically to address ventilation problems. Recently introduced into the United States, it involves setting up grids of ventilated cavities beneath normal concrete slabs. Ductwork, cabling, and wiring can traverse right through the grids. To form the cavities, builders lay out interconnected, domed, recycled-plastic forms—the Cupolex modules—reinforce them with steel or carbon fiber, and pour concrete over them.

According to Johnson, the new system gave his company some extra sales leverage when it came time to market their project. Plus, the savings the team achieved overall more than offset the $1 to $3 per square foot cost for Cupolex, which he admits is more expensive than traditional concrete slabbing. “It's an additional cost, but it will save more than it costs in the long run.”

Indoor air quality is fast becoming an industry cause celebre. Although its benefits are intangible, and seldom salable, everybody would like to offer higher indoor air quality, as long as they don't have to pay more to do so. What's more, it's one of those things that are really hard to define. Everybody knows what it isn't, but few agree on what it is.

Sure, ventilation and properly sized air conditioning units, heating, ducts, and fans are critical elements for good indoor air quality. For air-related subcultures, standards do exist. Acceptable whole-house ventilation rates are clearly spelled out by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (or ASHRAE 62.2), while the sizing of appropriate air conditioning, heating systems, and ductwork are established by Air Conditioning Contractors of America (or ACCA Manuals S, J, and D). Home Ventilating Institute guidelines even determine the correct sizing of kitchen and bathroom fans.

All of these standards and guidelines notwithstanding, IAQ is a slippery phenomenon. “You must look at the whole house—the entire system all working together,” says Brian Binash, president of Wilshire Homes in Houston, an NAHB director and the director of the Greater Houston Builders' Association. “It's pressure balances, how you bring in fresh air, the right size AC, the type of filter. You can't just look at one thing.”

According to building scientist Justin Wilson, founder and principal of consulting firm Building Performance Solutions of Denver, you can't even stop there. Local climate and site conditions come into play, too—average temperature and humidity, sun exposure, wind, rainfall, whether the dominant environment requires heating or cooling, and how water will be removed from the site, especially when it rains. “Builders should be a little more analytical so they put the pieces together properly,” Wilson says. “Everything affects everything else.”

In cases involving the desert, energy savings is top of mind. In its battle for progress against the elements, Las Vegas-based Sun-West Homes recently has adopted a new DuPont breathable membrane product called AtticWrap, which, when installed over rafters and trusses, seals an attic. Simply put, if you prevent outside air from coming in, you save energy. So Sun-West decided to develop a test house. Quickly, an unexpected benefit emerged from its pilot house project: improved indoor air quality.

The reason? As normal roof ventilation allows outside air into attics, it does more than drain energy efficiency. Water vapor in the air absorbs into the wood beneath the tarpaper sheathing, condenses, and eventually, leads to mold and mildew. Roof leaks create the same problems and can rot insulation over time.

With AtticWrap, “moisture escapes through micropores in the membrane to the outside instead of letting moisture in from the outside air,” says Arturo Horta, product manager at DuPont. “It gets rid of moisture and protects insulation and wood.” AtticWrap also resists liquid water. Horta says, “It's like a tent. It sends water straight to the gutter or soffit.”

Since mold has become a major issue in Las Vegas, the opportunity to prevent it—and the inferior IAQ that it breeds—was a huge benefit to Carl Martinez, Sun-West vice president of construction; one that justifies any increased costs.

According to Martinez, wrapping Sun-West's test house attic with the product cost $7,000 more than traditional sheathing methods, and took an extra day-and-a-half to install. He expects the extra cost to drop to $5,000 and the extra installation time to level off at perhaps one added work day.

Still, that's a lot less than the possible alternative: “AtticWrap prevents mold and reduces the need for mold remediation, which is very expensive. We'll be installing it in about 20 to 25 homes this year,” Martinez says.

Roofs are not the only place to watch when it comes to structures prone to moisture and its ill effects on indoor air. Chris Ellis and Gene Baker, co-presidents of Scottsdale, Ariz.-based Hallcraft Homes, constantly are on the lookout for ways to keep their homes dry. “Any wet area in a home is a concern,” Ellis says. “We want to prevent any water-related problems, such as humidity, mold and mildew.”

A chronic sore spot: wallboard. Ordinary paper-clad gypsum wallboard lacks water resistance. When it gets damp, it can stay that way, breeding mold and mildew. Conventional wallboard can reduce indoor air quality in areas prone to dampness—like kitchens or laundry rooms—or where there's sustained moisture, such as showers.

So when they found out that United States Gypsum's new Fiberock Aqua-Tough panels earned a 10—the highest score possible—on the Association of Standards Materials' tests for water resistance, the pair was immediately intrigued. Ordinary wallboard scores a zero in the test.

Lacking a paper facing, the product's structural strength comes from cellulose fibers uniformly distributed throughout the gypsum. Hallcraft aggressively researched and tested the product for four months. At one point, he even submerged a panel in water for seven days and then pummeled it with a hammer. The panel neither broke nor split. Convinced of its benefits, the company plans to install Aqua-Tough in 165 houses in the Tucson and Phoenix area in 2006.

Although Aqua-Tough costs Hallcraft about 15 percent more per panel than standard wallboard, the company limits its use to areas within five feet of water. “On average, this means about $45 per house,” Ellis says.

For efficiency to be optimum, it's important to have a “tight” home. But if a tight home isn't ventilated properly, indoor air grows stale. In 2003, Louisville, Colo., green builder McStain Neighborhoods tested the air exchange frequency of its homes and found that it took three hours to replace all the indoor air with fresh air. This was before ASHRAE 62.2 established a standard on the issue: three complete air exchanges per hour. “We knew we needed more exchange than we had,” says Jeff Medanich, special projects manager.

McStain's solution? Lipidex AirCyclers, which attach to a home's HVAC duct system. “A timer activates a motorized damper on the return side of the HVAC system,” Medanich says. “Air is temperature-conditioned and filtered before distribution into the house through the duct system.” McStain has installed Lipidex's system in 800 to 1,000 homes since 2003.

With timed ventilation via the AirCyclers, air in the whole house is mixed. “This eliminates high-humidity and hot or cold spots,” asserts Jason Wolfson, Lipidex president. “It averages out any problems.” No special ducts are required for the Air-Cyclers, and the timer/controller unit costs a production builder about $200, including installation. For Medanich, the cost is no deal-killer, and McStain, to date, hasn't attempted to pass it on to home buyers.

Wilshire Homes' Binash says his company will address IAQ issues with Broan's whole-house HEPA fresh air systems. Together with partner Wilshire Homes of Texas in Austin, the companies will include the system in nearly 1,000 homes in Austin, San Antonio, and Houston in 2006. “The system filters to such a fine degree that it really gets rid of nearly all contaminants,” Binash says. “It cuts back on dust and pollen.”

The fresh air systems, formerly known as Guardian Plus, can operate independently or attach to an existing HVAC system. “If put in during construction, it's no different from putting in any other air-handling system,” Collins says. “There's a little extra ductwork to install it.

IAQ innovations are abundant. Here's how a handful of manufacturers are making news:

Product: Bryant Perfect Air Purifier

Company: Bryant Heating & Cooling Systems

Product: Ultra-Aire whole house dehumidifier/ventilator/filter system

Company: Therma-Stor Products

Product: ProMark Total Spectrum Air Filtration System

Company: ProMark Associates

Product: Dehumidifying Ventilators and Air Purification Systems

Company: Healthy Air USA