Frame a Home for Energy Efficiency (House Framing for Energy Efficiency)
Posted in Construction How-To Energy Efficiency Framing
Frame a New Home or Addition for Energy Efficiency.
Anyone contemplating an energy-efficient room addition or building their own home has likely given careful thought to the insulation. Which material is best? What thickness should be used? Is the R-value sufficient? But often they ignore the structural framing, which holds everything together. It doesn’t matter how good the insulation is if air leaks around it; the design and placement of the studs, joists, headers and other framing members affects how well the insulation can do its job.
Framing techniques your grandfather didn’t know, and your dad may not have taught you, can help reduce heating and cooling costs—and use less wood. The trick is to lay out the framing in ways that help eliminate gaps in the insulation and that lessen the number of thermal bridges through the framing members. While not difficult to build, these methods require advanced planning. Your building material dealer may be able to assist with software that can turn a basic home plan into detailed drawings showing energy-efficient framing.
Advanced Framing Methods
The National Association of Home Builders (NAHB) developed so-called “advanced framing” methods (also known as “optimum value engineering” or OVE) several decades ago. Don’t let the names frighten you. The practices are relatively straightforward, just different from how framing is traditionally constructed. They include (Figure 1):
• 2 x 6 studs at 24-inch on-center (OC) spacing
• Two-stud corners
• Ladder blocking at wall junctions
• Double rim board and insulating foam in lieu of headers
• In-line framing
• Single top plate
• Minimal trimmers or jack studs
As an example of the potential benefits of these methods, iLevel by Weyerhaeuser built a 24-inch OC demonstration wall with 2 x 6 studs that achieved an 86-percent increase in insulation volume and a 58-percent increase in the wall’s overall R-value, compared to a traditional 2 x 4 wall at 16-inch OC spacing. Further, the demonstration wall used 8 percent less wood volume. The U.S. Dept. of Energy estimates that advanced framing can reduce annual heating and cooling costs up to 5 percent, and for a 2,400-square-foot house, save up to $1,000 in materials.
