A new type of steel wall stud for home construction, which improves energy efficiency of wall systems at least 10 percent, has been tested in the Buildings Technology Center at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL).
LeRoy Landers, a professor of architecture at the University of Pennsylvania and a candidate for a doctorate in architecture design, conducted a series of tests as a user of the Buildings Technology Center test equipment. The tests revealed his stud design performed in residential walls with 10 to 15 percent more energy efficiency than conventional steel studs.
The improved thermal performance is due to reducing the surface contact of the metal stud with the inside and outside wall sheathing. This is usually drywall on the interior and plywood or oriented strand board on the exterior. The part of the steel stud that touches the attached sheathing (flange) is bent in toward the center of the wall. This leaves only the vertical edges of the indented flange contacting the sheathing, forming metallic channels the full length of the stud where it is fastened to the interior and exterior sheathing.
Landers conducted his research with the assistance of Andre Desjarlais, a research engineer with the Buildings Technology Center.
The experimental steel stud was tested in a wall with one-half-inch gypsum board sheathing on one side and plywood on the other, with fiberglass cavity insulation. Landers tested the walls with a temperature of 50 degrees Fahrenheit on one surface and 100 degrees Fahrenheit on the other.
Landers became interested in improving the energy efficiency of steel studs after working as an architect in Seattle.
"Steel studs we were using in new buildings were not meeting energy codes," said Landers, an Oregon native who moved to Philadelphia, joining the University of Pennsylvania faculty to work on his doctorate.
While steel studs are common in commercial construction, wood studs have been preferred in residential construction mainly because of cost. Landers said the construction industry is moving in the direction of more steel studs for residential construction. Compared to conventional steel studs, Landers noted use of his steel stud design improves energy efficiency at virtually no cost .
"Steel is getting cheaper than wood and the quality of steel is better," said Landers, explaining the increased interest in steel studs. "Other advantages are mold does not grow on steel as it does on wood, steel can be recycled, you cut down on your chances of termite damage and you don't have to use chemicals to battle those termites."
Landers plans to take the data he recorded during his work at ORNL and distribute it to the construction industry and to those involved in building codes enforcement. He also plans to do additional testing of steel studs with masonry, wood and other building materials.
Jeff Christian, director of the Buildings Technology Center, said he hopes Landers' work will pave the way to "level the playing field" for building material suppliers.
"I hope our measurements on this and other innovative wall systems will change the building envelope two or three years from now, and that tomorrow's choices are more energy efficient," Christian said. "We base our calculations for wall thermal performance on not only the energy passing through insulation. You have to look at the whole wall, including all the structural parts like the studs and materials used to hold walls to other walls, doors, windows, roofs and floors.
"It is our goal to offer the building industry a method of developing a new consumer label which represents the whole wall and not just the R-value rating on insulation," Christian added.
ORNL's Buildings Technology Center is funded by DOE's Office of Building Technologies.
You can learn more about this research on the Buildings Technology Center's World Wide Web home page. For additional information, call ORNL Public Affairs, 865-574-4160.
ORNL, one of DOE's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Systems, which also manages the Oak Ridge K-25 Site and the Oak Ridge Y-12 Plant