Advanced Framing Builds on Love of Wood

"In the past, framers have used wood much like drunken sailors on leave spend money. "
- Joe Lstiburek, Builder's Guide

To cite the obvious: builders love wood. About 85 percent of new homes are framed with it. It's a dependable, convenient and widely available framing product. Certainly in Colorado and other northern-tier states, wood framing is the norm.

Building inspectors know wood. Residential framers really know wood. Yet visit most building sites around town and the informed observer will typically be able to pick out unnecessary wood in the standard new home skeleton.

"Despite our history with wood, we still have a lot to learn," Steve Baczek told attendees at the Energy and Environmental Building Association's (EEBA) annual conference last fall. Baczek works for Building Science Corporation (Westfield, Mass.), a Building America consulting team funded by the U.S. Dept. of Energy. He leads their efforts to convert Building America clients over to advanced framing. The record is mixed, but they're gaining ground.

"Between 30 percent and 40 percent of our production builder clients use advanced framing today," said Baczek.

What is advanced framing?

Baczek explained that advanced framing is simply the optimum use of wood. The system provides the most value per unit cost. It implies the most practical application of a wood frame.

One key element of advanced framing is OVE: Optimum Value Engineering, a program developed by the Forest Products Laboratory and the National Association of Home Builders roughly two decades ago.

Some of advanced framing's features are well known: studs on 24-inch centers, appropriately sized headers, stacked framing to eliminate the need for double top plates, two-stud corners, and ladder blocking where partitions meet outside walls. But at its best, advanced framing starts back at the design phase, when house framing based on 24-inch modules really helps optimize overall material efficiency.

"We should be designing buildings that coordinate advance framing practices with material availability and also integrate them with building envelope design and mechanical system layout," said Baczek. In other words, advanced framing is part and parcel of integrated systems thinking.

Joe Lstiburek, Baczek's boss at Building Science Corp., likes to ask audiences a closely related design question: would it cost less to build a 7-by-7-foot or an 8-by8-foot tool shed? "The answer is obvious," says Lstiburek. "While both shacks require the same amount of material, the smaller shack takes longer and costs more to build because of the additional framing labor plus paying to haul more trash to the landfill."

Lstiburek then asks obvious follow-up questions: why don't we design houses on 24-inch modules and why don't we specify more roof trusses that eliminate wasted decking material?

(Note: In the coming months, Lstiburek will give five day-long seminars about building high-performance homes. The schedule includes Denver (February 22), Summit County (February 26), Fort Collins (March 4) and Colorado Springs (March 7). For details, call the HBA at 303-778-1400 or E-Star at 303-297-7498.)

Why reinvent the wheel?

Baczek states that advanced framing improves project quality, reduces initial material cost, time and labor, and solves existing problems.

"Consider wasted wood," said Baczek. "Builders pay for it four times: once to buy it, again to move it around, yet again to toss it out and finally to haul it away."

But the combination of higher performance for the same cost is the most compelling reason that the Building America teams push advanced framing. Their case studies (see below) show that it costs the same or less to frame with 2-by-6, 24-inch O.C. framing with R-19 batts as it does to frame 2-by-4, 16-inch O.C. with batts.

"When you do it smart, on day one you put dollars in the builder's pocket. On day two, you put money in the owner's pocket, thanks to the better insulated shell. You improve long-term durability, which again puts dollars in the builder's and buyer's pockets. You also reduce environmental impacts." What's not to like?

The process

"Advanced framing is a series of choices, not simply a method of woodframe construction," said Baczek. He highlights five phases of the process.

First, there's the information phase. "You're here aren't you'?" Baczek pointed out to his audience.

Next comes the speculation phase. Builders quickly start asking what might or might not work. Could it solve some existing problems'? Some like the notion of reduced drywall cracking- a prime benefit for Town & Country Homes in Chicago. At the EEBA conference, T&C's Frank Beardsley reported that they reduced their warranty callbacks on their annual 750 homes by roughly $1,000 per home, primarily from reduced drywall cracking that came with the switch to advanced framing.

Baczek admits that during the speculation phase, builder concerns tend to focus on code issues, subcontractor mindsets and the homebuyer's preconceived notion that 16-inch O.C. framing is the preferred way to go.

Third is what Baczek calls the analysis phase. The issues identified during the previous phase need to be prioritized. "During this phase, you have to choose which battles to fight."

Then comes the development phase. At this point, company planners need to select details for their applications, plus the procedures for implementing them. The final step is implementation.

Getting it done

Baczek sees five steps to implementation: planning, purchasing, building, assessing and marketing.

To make planning easier, he points out that codes have approved 2-by-4, 24-inch O.C. for single-story homes and 2-by-6, 24-inch O.C. for two-story homes with stacked framing. They also allow use of a single top plate, provided the plate is adequately tied at joints (see Figure I, p. 34).

"During pre-construction, we provide drawings that integrate advanced framing into complete building envelope design and mechanical system layout." The devil is in the details. As stacked framing is laid out on drawings, small items like header size, or elimination of headers above nonbearing walls, are all clarified. Systems engineering calls for either insetting metal bracing or innovative shear panels that provide stronger protection against earthquakes and other large building loads than 100 percent OSB sheathing with standard nailing patterns. A pre-construction meeting helps explain this and other issues to all project contractors.

At the purchasing level, key issues involve obtaining custom-cut studs for the systems as designed. Baczek also encourages green-building strategies: purchasing framing materials from sustainably harvested lumber operations that have been certified as such.

During construction, Baczek stresses the need to eliminate on-site engineering assumptions by making sure the plans supplied to framers are complete. As construction starts, it's critical to have full buy-in from the framing crew.

Assessment means establishing what's working, then responding by either changing a few details or pushing for more. When it comes to marketing, Baczek recommends selling the related energy efficiency as well as touting the demonstrated environmental responsibility and leadership.

Case study #1

In the San Francisco area, consider the home described in Figure 2 (see p.14). It contains some typical elements, such as 15 percent of the exterior wall consisting of windows and doors.

Three key results: first, switching to advanced framing saved the builder $1,117. Second, the advanced wall's heating and cooling loads were decreased by close to 40 percent, allowing a downsizing in cooling equipment by about 1.5 tons. Third, the homeowner saves $293 a year on their energy bills.

Case study #2

In Grayslake, III., northwest of Chicago, the entire subdivision of more than 350 homes called Prairie Crossing was constructed to the Building America program criteria. Included in that package was advanced framing. The homes, first started in 1996, each included the cost factors listed in Figure 3 (see p. 13). Note that savings achieved by upgrading from traditional 2-by-4 to advanced 2-by-6 were roughly $250 per home. That helped reduce the cost of other upgrades in these high-performance homes.

For more details on advanced framing, Baczek's 77-slide power-point presentation is available at www.buildingscience.com/resources/presentations/advanced_framing.pdf. It's worth a visit, if for no other reason that to see his last slide wherein he forecasts the future of traditional 2-by-4 framing.

Steve Andrews consults with builders for E-Star Colorado and writes on energy issues (sbandrews@att.net). E-Star (www.e-star.com), is a nonprofit home energy rating system that works with both new and existing homes statewide.

2008 Built Green Colorado

Home Builders Association of Metro Denver, 9033 E. Easter Place, Suite 200, Centennial, CO 80112
(303) 778-1400 fax: (303) 733-9440  info@builtgreen.org

Last Updated: 10/05/2007