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Building a Better Place to Live
The NAHB Research Center, a subsidiary of the National Association of Home Builders, applies new technology and tried-and-true techniques to develop better housing for diverse groups
By Tom Gibson
As I walked into the lobby at the NAHB Research Center, a special event was taking place. Close inspection revealed it as the Aging in Place competition, a contest in which college students design homes for seniors. Artist renderings and blueprints of house designs stood on display, and people milled around chatting and perusing the drawings. A spread of food and bottles of sparkling cider occupied a table. People gathered around to hear luminaries speak, and Liza Bowles, president of the research center, started by proclaiming, "This is our second Aging in Place Contest. We're proud of it. Entries are up this year."
An
event such as this epitomizes part of the unique mission of the NAHB Research
Center in Upper Marlboro, Maryland. On one hand, they research the nuts-and-bolts
-- or in this case, nails-and-wood -- aspects of the design and construction
of homes. But on another level, they also wrestle with some of society's
most important issues such as affordable housing for lower-income people,
housing for the elderly and disabled, and the environment.
Founded in 1964, the Research Center is a subsidiary of the National Association of Home Builders, an organization of builders, remodelers, manufacturers, and other housing professionals. The center aims to keep builders abreast of technology while improving the quality and affordability of housing. Staff includes scientists, engineers, social scientists, architects, planners, analysts, computer specialists, laboratory technicians, and builders. The Research Center's affiliation with NAHB allows it to carry out its diverse mission, as it provides access to homebuilding practitioners -- NAHB members often participate in studies and field tests.
On a tour of the Research Center's facility, Jay Crandell, director of structures and materials, states, "A lot of engineering sciences go into housing." One of their goals is to explain and quantify the engineering characteristics of materials and techniques that people have used for many decades to build houses but didn't necessarily understand. "We're going back and reverse engineering." His group creates engineering standards for materials such as wood, steel, and concrete.
Crandell graduated from Virginia Tech with a B.S. in agricultural engineering, having gotten into the field because he had an interest in wood engineering. He has also taken several courses in civil and structural engineering along the way. Before joining the research center, he worked as a construction manager and field engineer for a general contracting business that specialized in foundations and coastal construction.
On a tour of the Research Center's material and structural systems testing laboratory, Crandell showed me a 200,000-pound Universal machine for testing walls to determine their compressive strength. They use fixtures like this to conduct testing and certification programs for public and private sector clients. Jobs range from thermal conductivity tests on insulation to wind, water, and structural tests on windows and doors. Much of the work involves studying alternatives to conventional lumber and plywood, including products such as engineered wood, laminated fiberboard structural sheathing, light-gauge steel framing, structural insulated panels, insulating concrete form wall and roof systems, and lightweight concrete blocks.
Bob
Hill, director of laboratory services and a mechanical engineer, took
me to a section of the lab where they test fixtures such as bath tubs,
sinks, shower stalls, and garbage disposals. They can put a structural
load on them, do thermal cycling, and test for stains, cigarette burns,
and flammability. Then he showed me a large sheet metal box with PVC piping
in it. "This is our wind-driven rain chamber." They use it to
test the effect of rain blowing onto siding and house sections.
It becomes apparent Crandell and Hill enjoy the work here. "You get to do very interesting things," Crandell says. "An engineer couldn't be in a better position in terms of the learning opportunities we get exposed to here." As part of the reward, "A lot of the stuff we've done has become practice." He cites a case where a change in a building code they instigated saved $300,000 on the construction of a 100-unit low-income housing project in Denver.
Of course, much of the testing the Research Center does goes beyond the lab. As Crandell explains, "Our lab extends out to the entire U.S." One of their main projects, the Partnership for Advancing Technology in Housing (PATH) fosters the creation and widespread use of advanced technologies to improve the quality, durability, environmental performance, and affordability of housing. Under the program, the research center maintains a collection of housing projects throughout the U.S. that use new technologies and innovations. The inventory provides case history information on a range of projects, from individual homes to entire subdivisions.
As an example of a PATH project, Bruce Davis Construction, Inc. is building the 80-unit Washington Square community of townhouses and duplexes in La Plata, Maryland for independent and active senior citizens. The homes are designed with insulating concrete forms (ICFs) to provide energy-efficient and durable exterior walls as well as interior steel framing and steel floor joists. Other technologies include tubular skylights, fiber-cement siding, cost-effective ventilation systems, and tankless water heaters.
Closer to home, the Research Center tests new technologies by building houses in the NAHB National Research Home Park in nearby Bowie, Maryland. Driving through, it looks like a typical sprawling suburban housing development . . . because it is. After building a home there, they typically test it for a year and then sell it for occupancy in normal fashion, although they've kept some units for up to five years. When selling a house, they may install a data logger in the walls that the consumer never sees, to monitor energy consumption or environmental conditions.
In one of its more exciting recent projects, the research center is collaborating with PATH to build two of what they call Marketable, Affordable, Durable, Entry-level (MADE) single-family detached homes in the Research Home Park. These will mix and match technologies and building practices to create an affordable home that will appeal to a broad range of consumers. Housing experts say a large gap exists between first-time buyers' expectations and what they can actually afford, and the market in many areas is shifting away from entry-level homes toward the move-up buyer.
Along
a semi-circular street in another area of the Research Home Park sat a
row of test houses built by the Research Center in recent years. One was
the Firesafe Adaptable House, which demonstrates techniques for making
homes more livable, adaptable, and accessible without appearing institutional.
Next door, the Resource Conservation Research Home highlights materials
and systems that conserve material and energy resources. This not only
makes extensive use of recycled materials, but also products that increase
energy efficiency, use less precious material, increase durability, and
require less maintenance.
This illustrates the expanding focus green building has taken in recent years, one beyond the usual energy efficiency. The Research Center researches thermal performance, water conservation, efficient HVAC systems, construction waste management techniques, and efficient use of building materials. One program had them characterizing the performance of five geothermal heating and cooling systems, and another study focused on minimizing hot water energy use with innovative distribution systems and water heating equipment. The center also helps developers reduce the environmental impacts of land development.
But though they address environmental home building, the Research Center engineers take a guarded approach with it. "From a marketplace perspective, there isn't a lot of demand. If a homebuyer is looking to spend an extra thousand dollars on a house, they want granite counter tops rather than more insulation in the walls," Hill says. "The technology is certainly there. But whether it's cost effective in today's marketplace is still being determined."
On the other hand, the need for senior housing is more straightforward, as the 60-plus age group in America is expected to double by 2025. The research center created the National Center for Seniors' Housing Research to develop innovative solutions for accommodating the lifestyles of today's older Americans. The Research Center created a Directory of Accessible Building Products in the late 1980s to help builders, remodelers, and consumers meet the needs of aging and physically limited populations.
Crandell and Hill thrive on the technical aspect of their work, but they also appreciate the headway they're making on social issues. "That's the reward of solving some of these problems," Crandell says. It all comes as part of the unique dual mission the Research Center has created for itself.
Just What is a MADE House?
Chad Garner, construction and project manager for the Research Center's Marketable, Affordable, Durable, Entry-level (MADE) single-family detached home program, describes the project as "balancing affordability with durability." He adds, "The major focus was design and getting away from the bigger-the-box mentality."
In simple terms, MADE involves repackaging existing homebuilding techniques in unconventional ways and mixing in new technology. The two houses currently under construction at the Research Center's Research Home Park will have 1-1/2 floors. Because they use stick framing for the roof instead of trusses, the second floor becomes living and storage space instead of an attic. Another overarching concept: leave sections of homes unfinished for future expansion as a family grows in income and number.
Numerous other features permeate the design. The houses have an 18-inch roof overhang on all sides to keep rain off the sides, so siding and underneath structure last longer. Porches are covered for shading and increased durability. HVAC lines run in conditioned space -- through the floor -- to save energy. You'll see no roof penetrations on the homes. Instead of running vent lines to the roof for helping water flow down drains, they use air admittance valves, actually a check valve that works on negative pressure. When water flows down a drain, the valve opens and lets air in, but sewer gas can't flow in the reverse direction.
In the basement of one of the homes, Garner showed me a slew of wiring and coaxial cable they've installed for security, smart features, and data outlets. "These are very well developed technologies we're using here," he emphasizes. "We don't use new technology for the sake of technology." With the system, the owners will be able to control functions such as thermostats and lights from a cell phone. "We put plenty of wiring in the walls. We thought that was a good investment for the future."
Then Garner showed me precast concrete walls used for the basement, saying it helps with labor problems because sometimes it's hard to get concrete workers. "The speed is tremendous."
The heat pump in the basement
sports a SEER (seasonable energy efficiency rating) of 12, prompting Garner
to says they're reasonable but not extravagant with energy efficiency.
Walls are insulated to R-15 and R-30, and the ceiling to R-38.
Outside, Garner showed off flashing materials and techniques they use around windows to keep water out. Wetness sensors were mounted along an outside wall, and at the bottom, a plastic gutter ran its length to collect rainwater in a tube so they can measure the amount of water hitting the wall. They will compare that with data from the sensors to see how much water is hitting the outside and seeping through to the inside. "I've never heard of anybody doing that on a whole wall. We did that in the lab, and it worked really well," Garner reports.
The Research Center has encountered many problems with neighbors and regulators in building the MADE houses. Most notably, neighbors have taken the research center to court claiming the smaller size of the houses will bring down property values, even though as Garner says, they're built much better than surrounding ones. But he points out that discovering and resolving these types of problems in the prototype stage forms an integral part of the project. "That's the whole idea of building these research homes."
For more information on the National Association of Home Builders Research Center, visit www.nahbrc.org.
Progressive
Engineer
Editor: Tom Gibson
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©2004 Progressive Engineer