While they like the idea, Veridian execs haven't yet decided whether to pursue LEED for Homes verification on every home Veridian builds. And the company also hasn't completely adopted advanced framing. “We've picked up some of the secrets,” explains Gary Zajicek, Veridian's vice president for construction, “but we're still working on some areas where we could really make this thing fly.”
MULTIPLE CHOICE: Steve Baczek of 3-D Building Solutions supplies builder clients with dozens of drawings in PDF format, illustrating appropriate framing, insulating, air-sealing, and rain-shedding details. Shown here are three of Baczek's options for constructing a common assembly: the intersection of a 2x4 interior partition wall with an insulated exterior 2x6 wall. Alternative 1 uses a 1x6 backer applied to the back side of the end 2x4 stud; drywall is fastened to the 1x6 at the inside corners. Alternative 2 provides for horizontal ladder blocking to be placed inside the exterior wall stud cavity. The end stud of the 2x4 wall is fastened to the ladder blocking, and the horizontal blocks provide an attachment point for dry-wall screws at the inside corner joint. Alternative 3, like alternative 2, uses horizontal ladder blocking, but the exterior wall is insulated and drywalled before the interior wall frame is butted to it, so that the gypsum wallboard is continuous behind the joint (which helps the drywall work as an effective air barrier at that corner).
For example, Steven Winter is helping Veridian re-engineer its plans to allow stack framing, “lining up our floor system I-joists with our studs and our trusses,” says Zajicek. “Right now, we set floor joists at 19.2 inches on center and wall studs and trusses at 2-foot centers. But we'd like to have our floor joists centered at 2 feet as well so we have optimum line-up for our mechanical systems.” (In that case, wall framers could also pare down to a single top plate. See “Streamlining the Structure,” page 254.)
Both New Town and Veridian are production builders, completing hundreds of homes a year from standard plans, using trade contractor labor. So for each company, standardizing and communicating its framing and insulation practices is a continuing challenge, and introducing new, unfamiliar methods adds yet another twist. As they change their ways of building, both builders have had to retrain their on-site labor forces in the modified methods. But first, each builder has had to make its own decisions about just how to update its standard framing systems.DETAILS, DETAILS
Most beginning frame carpenters learn the same simple routine on the job: studs 16 inches on center, with doubled or tripled 2x8s, 2x10s, or 2x12s for headers. The bigger the header, the more jack studs you place to support it and the more king studs you set next to the opening—and when in doubt, one more won't hurt.
WARM AND SNUG: Eliminating unnecessary cripples under the rough windowsill leaves more room for insulation. It takes time to educate framers about small, but important, energy-efficient details such as this, says New Town Homes' Bill Rectanus.
Advanced framing takes a little more thought and some relearning—and good drawings are important, too. Registered architect Steven Baczek produces the detail drawings, such as the examples shown above, for 3-D Building Solutions. “There's no set-in-stone procedure,” says Baczek. “We have at least 40 different details builders can use, and it's up to the builder. One builder might choose these 16 details and run with them, another builder might choose these 24.”
New Town took Baczek's drawings into a meeting with the company's architects. “We sat down and went through all the details,” says Rectanus. “We said, ‘OK, let's use choice one on this detail, choice two on this detail, choice three on this detail'—and then they incorporated those into the blueprints for every plan we build.”
Now, New Town is phasing in the system on its half dozen Denver developments. “You find yourself concentrating first on the details that deliver the most bang for the buck,” says Rectanus, “and on the ones that are going to cause you the greatest problem if they aren't done right.” For instance, 2-foot on-center spacing is easy to pick up; but other details, such as two-stud wall corners or right-sized headers, are more complicated.
- Two-stud corners. Traditional framing uses three studs, and often some added blocking, to frame a corner where two walls intersect. That assembly is hard to insulate and wastes wood, say building scientists—and there are many better alternatives. Veridian Homes trains its drywallers to use drywall clips at that corner location (for product examples, see www.prest-on.com or www.thenailer.com). But Rectanus says that most of New Town's drywall companies don't like the clips. “So having a framer put in an extra piece of 1x backing seems to be easier on the job,” he notes, “and it still lets us get plenty of insulation in there.” Baczek points to other variations, as well. “I've also seen guys use corner bead, inverted,” he says. “There must be 10 or 12 different ways to do that corner.”
Many builders resist the notion of pared-down corners, Baczek notes. “Builders take pride in saying, ‘I build a nice, sound house. It's got to be solid.'” But that's a misconception, he says: “Drywall really wants a flexible corner—because the wood is certainly going to move at a different rate than the drywall.”
Over-fastening drywall can be a recipe for cracks and callbacks, agrees Veridian's Zajicek, especially at wall-to-ceiling joints: “The top part of the attic truss will move differently than the part that is surrounded by insulation and conditioned. And that creates a lot of stress on the wall/ceiling line. So we don't even put nailers at the ceiling line—we just clip the drywall to the wall and let it float.”
- Right-sized headers. Stud spacing is key in a clear wall section (a wall area composed of just studs and insulation, with no framed-out openings or other extra framing). But window and door framing can still load up the wall with extra wood. “Some engineers will say, ‘OK, your biggest header in this house is a triple 2x12, so we'll just put a triple 2x12 everywhere. That way, the framer doesn't have to worry about getting it wrong,'” Rectanus explains. “But we said, ‘Absolutely not. If it's a double, I want a double. If it's a 2x6, I want a 2x6.' You size them right to minimize the excessive lumber usage.”
Better still, says Rectanus, designers can switch to engineered lumber headers. “Forget all these different sizes—I can use a single-ply 1 ¾ x 8 or a 1 ¾ x 6 LVL [laminated veneer lumber] on every header. Then, I can put foam insulation on the back side of that and really increase insulation value.”