A quiet revolution--save for the whine of screw guns--is underway at the corner of Culver Drive and Bryan Avenue in Irvine, where Lennar Homes is building 203 homes with steel-framed panels.
The lightweight, galvanized steel studs used in these panels replace the wood studs that have been used to frame houses since the mid-1800s and don't require sawing and fastening together on the site in the traditional "stick-built" fashion. Instead, the panels are planned in a computer, assembled in a factory and shipped to the site to be put together like a giant Erector set.
They represent the latest development in a decade-long effort to transform the way homes are built and further a trend to build homes out of pre-assembled components.
Framing homes with steel has appealed to builders for years. Wood from younger trees harvested today tends to twist and warp more than lumber from the old-growth trees cut down in the mid-20th century. And steel prices tend to be more stable than lumber.
But there are fewer places to buy steel than lumber, and few carpenters who know how to work with it. Building codes have been slow in adopting standards for steel use, and many code officials are unfamiliar with it. Plus, steel studs take longer to cut and screw than wood, resulting in higher labor costs.
Panelizing the wall sections in a mass-production, factory environment, however, cuts the cost of on-site construction.
"This is one of the most significant possible changes in our industry," said Lennar's David Ball, who was hired five months ago to help the company shift from wood studs to steel panels.
Lennar Homes, which builds 23,000 homes a year in the country--about 5,000 in California--had not used steel framing in a big way until last year, when Paul DiGiovanni, president of American Steel Builders in Commerce, talked Lennar into using the galvanized steel panels his company manufactures for the last phase of its Camrosa development in Anaheim.
Most enticing to Lennar was the speed with which the panels could be put up. Whereas framing a house with wood took Lennar's framing contractor about 22 days, framing with steel panels takes about 10 to 14 days.
The ability to frame a house quickly, for less, is motivating the company to eventually frame all its homes with steel panels. This represents a significant resolve for a big player in an industry which, as Balls said, "doesn't change very much."
"We believe in it," said Jeff Roos, president of Lennar's Southern California operations. "We feel steel is superior to wood, and panels are superior to [steel] stick-built."
Tests Are Touting Steel
as Superior for Framing
Scores of studies and tests tout steel as a superior material to frame many of the 1.2 million single-family homes built in the country each year, but barely 1% of homes are framed with steel. That percentage jumps to 5% if interior partition (non-load-bearing) walls are included.
Among those lauding steel's benefits is Nader Elhajj, an engineer with the National Assn. of Home Builders Research Center, which also studied building with insulating concrete forms and structural insulated panels of wood product sandwiched over solid foam.
"We found steel would be the best choice for replacing wood," Elhajj said.
Especially in earthquake-prone Southern California, framing with lightweight galvanized steel makes sense.
"It doesn't collapse suddenly," Elhajj said. "It tends to give."
And it really makes sense in Hawaii, home of voracious Formosan termites, where 50% of the homes are framed in steel.
In colder climates, though, steel is less practical because the studs act as a high-efficiency transmitter of heat from inside the house to the outside. One solution is to attach a solid layer of insulating foam between the studs and the exterior siding or stucco, but that adds enormous costs in materials and labor.
Though steel's thermal-bridging characteristic poses less of a problem in Southern California, it still is a consideration for homes to meet energy-efficiency codes. Lennar's homes use a specially designed "thermal stud" that minimizes the heat loss (or cooling loss in summer), but the product is expensive and is only available through one source.
Studies to find and test alternatives to wood began in earnest in the early 1990s, when the cost of framing lumber jumped from $219 a thousand board-feet (the standard by which lumber is measured) in March of 1991 to $454 in March of 1993, according to Random Lengths, an industry publisher that reports on lumber prices.
The price increase, coupled with complaints about a decline in lumber quality (a U.S. Department of Housing and Urban Development report states that the density of framing lumber has decreased 10% in the last few decades), motivated builders to look at alternatives.
Last week's price was $330 a thousand board-feet, but May's average of $402 caused some to predict that another upswing was on the way.