Episode Three: Framing & Roofing

Steel vs. Wood Framing

"Since California is earthquake country, we'll have to erect a post-and-beam structure to support the straw bales. It can be made of wood or steel, and I found a lot of benefits for using steel on this project."

Kevin visits green architect Eric Corey Freed to discuss the environmental differences between using wood and steel for the post-and-beam structure of his new home. As Eric explains, there are actually pros and cons to each. Because there is a large amount of energy that goes into the processing of steel, and because wood is a renewable resource, he often chooses to use wood. However, steel can be a good alternative if you need its strength and span. In earthquake-prone California, strength and span is exactly what Kevin is looking for to secure his straw bales. Although wood is often considered a greener choice, because of the size of the home, this project would require more wood than a regular house, as well as huge beams from old growth trees to get the same sturdiness that steel will supply. Weighing all the factors, Kevin decides on a steel structure.

The Green Benefits of Steel Framing

Kevin meets with contractor Sergio Michel, who is in the process of building a steel-frame home, to discuss the green benefits of steel framing. Sergio explains that several years ago he built another house in Los Angeles and that when the wood arrived from the lumberyard it was already infested with termites.Termites are a huge problem in California construction, and also present numerous health issues because the pesticides traditionally used to control them can be highly toxic. However, today there are many safer ways to deal with termites using freezing, heat, electricity, borate, salt and even orange oil. But, because termites don't eat steel or straw, and the only wood in the house will be in the windows, doors and eaves (highly accessible areas), managing termites should be an easy task. Additionally, steel won't need the chemical treatment that wood requires to prevent against termites and other wood-destroying insects. By using steel, those chemicals are eliminated from the indoor environment and from the environment of the framing crews and people who would have their hands on the chemicals every day.

Termites aside, steel-frame homes are also growing in popularity for other reasons. Our health expert Alyssa Alvord explains that the main reason steel framing is growing in popularity is mold. Mold needs food, moisture and specific temperatures to grow. Because wood is a breeding ground for mold and because mold causes rot, more and more people are turning toward steel framing. Steel has also proven cost-efficient for Kevin. "I got a bid of $100,000 to frame this entire house in wood. The comparable steel package consisting of heavy-gauge steel posts and beams, all of the light-gauge steel for the interior walls, and the roof framing will cost us $55,000. The bales will be about $2,600, so when we're done, we'll have eliminated the stick-framing for all of the exterior walls and the need for insulation in those same walls," he explains. Although labor will cost more, because screwing together the light gauge steel will take more time than nail-gunning studs, Kevin still has $42,000 to work with. Prices can fluctuate for steel and wood, but at the time construction began on Kevin's dream home, steel was more cost effective for his design. Kevin stops Rob Thayer, his light-gauge steel contractor, to discuss how using steel framing helps him stay green. "One of the biggest benefits," explains Rob," is, it's a recycled product. Sixty-six percent of the steel that's put out by the factories is from recycled steel products."

Designing a Functional Roof

Now that the framing is up, Kevin talks again to green architect Eric Corey Freed about roofing. Eric explains that one simple thing people living in warm climates can do is choose a light-colored roof. Roofs are typically a dark color, because they're made out of asphalt. And because dark colors absorb heat, in hot climates such as Arizona and California, the dark roofs heat up the buildings, sometimes by as much as 30 degrees more than they should. By simply choosing a lighter colored roof, you can reflect enough heat to cool your building down.

A Living Roof

"Another green option is to build a flat rooftop garden in areas with warmer climates. Plants have a natural reflection to light, so the structure will stay cooler in intense heat. It's a green extreme roofing choice," says Kevin. The Lady Bird Johnson Wildflower Center in Austin, Texas installed the first extensive green roof in their area. Kevin visits Director of Landscape Restoration Steve Windhager to find out how they designed their rooftop gardens. Steve shows Kevin how native plants can be used in green roof applications, particularly on commercial buildings. All living roofs are lined with a standard corrugated aluminum rooftop. On top of the metal are two waterproofing membranes that surround a sheet of foam, to keep the insides dry. Then, finally, about four inches of soil and plants are added. There are many benefits to rooftop gardens. Steve explains that living roofs are less likely to leak than any other kind of roof. Living roofs also reduce heat, and the insulation provided by the soil actually cools the buildings. The final benefit, of course, is wildlife. Living roofs can be a great habitat for birds, insects and other species. As much as Kevin would like to have a rooftop garden, county building codes in Santa Barbara will not allow them.

Rainwater Collection

Kevin chooses a standing seam metal roof for his dream home, for one special reason: Unlike wood, shake or concrete tile, a metal roof sheds all water. Kevin is interested in attaching a rainwater catchment system to his home, so he visits Richard Heinichen in Tank Town, Texas. Richard shows Kevin how he can use the roof of his house to collect rainwater and become independent of any other source for water. According to Richard, the average person uses 25 gallons of water per day. In a two-person household, 5,000 gallons would be needed to go 100 days; or 10,000 gallons to go 200 days. "Get a 10,000-gallon tank, and that's all of the domestic water you'll ever need," explains Richard. Cities like Austin, Texas, have even begun giving rebates on rainwater collection systems. Next week on Building Green: straw bales.