Advantages of Advanced Framing
Advanced framing produces energy efficient, structurally sound homes with lower material and labor costs than conventionally framed houses. The key advantages of advanced framing:
APA Senior Engineered Wood Specialist Bob Clark recently sat down with Rob Heselbarth, Editorial Director of Residential Design + Build magazine, to discuss the benefits of advanced framing. That interview is featured at www.forresidentialpros.com.
Advanced framing is a proven method for cost-effectively meeting energy code requirements. By maximizing space for cavity insulation and minimizing the potential for insulation voids, advanced framing delivers significant energy performance and cost savings for the builder.
Walls built with 2x6 wood framing spaced 24 inches on center have deeper, wider insulation cavities than conventional 2x4 framing spaced 16 inches on center. Increasing the amount of insulation inside the wall improves the whole wall R-value (resistance to heat flow). The table below (excepted from page 5 of the Advanced Framing Construction Guide) shows advanced framed R20 code-compliant wall systems provide a greater whole wall R-value than conventionally framed 2x6 walls or code-minimum 2x4 walls sheathed with foam.
In addition to maximizing space for cavity insulation, advanced framing simplifies the installation of insulation and air sealing. Conventional framing can leave voids and small cavities in the framing at wall intersections and corners that can be difficult to insulate and seal effectively. By installing fewer framing members, it is easier for the builder to apply complete insulation coverage and achieve a tighter building envelope.
As energy codes have become increasingly stringent, advanced framing has grown more popular in climate zones where high prescriptive wall R-values are mandated or desired. While framing with 2x6 studs spaced 16 inches on center is already common in many northern states with more restrictive energy demands, increasing stud spacing to 24 inches on center, insulating effectively, and fully sheathing with wood structural panels, such as plywood or oriented strand board (OSB), allows builders to cost-effectively balance energy and structural code requirements.
The ENERGY STAR® program was developed by the U.S. Environmental Protection Agency to promote the use of energy efficient products and practices. Advanced framing can help builders meet the requirements necessary to earn the ENERGY STAR label for new homes. Advanced framing techniques qualify as Reduced Thermal Bridging under section 4.4.5 of the Thermal Enclosure System Rater Checklist (ver. 3, rev. 5). These techniques must be incorporated to earn the ENERGY STAR label when using section 4.4.5 of the Checklist.
The framing width and spacing requirements for the Thermal Enclosure System Rater Checklist vary by climate zone:
- 16 inches on center (minimum) spacing if using 2x4 framing
- 24 inches on center (minimum) spacing if using 2x6 framing in colder climates (zones 5-8)
- 16 inches on center (minimum) spacing if using 2x6 framing in warmer climates (zones 1-4)
In addition, the following advanced framing techniques must also be incorporated to meet the thermal bridging requirements of the checklist:
- Insulated corners (R6 minimum). See page 10 of the Advanced Framing Construction Guide.
- Insulated headers (R3 minimum for 2x4 construction, R5 minimum for 2x6 construction). See page 13 of the Advanced Framing Construction Guide.
- Window and door framing, per opening — one pair of king studs, one pair of jack studs, and cripples only to maintain on-center spacing. Additional framing is allowed if required for structural support. See page 15 of the Advanced Framing Construction Guide.
- All interior-exterior wall intersections insulated to the same R-value as the rest of the exterior wall. See page 11 of the Advanced Framing Construction Guide.
By implementing these modest and cost-effective framing changes, ENERGY STAR builders can maintain their use of wood structural panel wall sheathing. Plywood and OSB wall sheathing allows for greater architectural flexibility in the number and location of door and window openings, often without necessitating re-engineering due to additional wall bracing area that is typically required with other types of wall sheathing.
Follow ENERGY STAR program guidelines for climate-specific installation requirements and recommendations. Visit www.energystar.gov for more information.
Advanced framing is less expensive because it is more resource efficient than conventional framing. By optimizing framing material use, the builder can cut floor and wall framing material costs by up to 30 percent while reducing framing installation labor.
Advanced framing can help to increase the efficiency of other trades as well; more space between framing members means fewer studs for plumbers and electricians to drill through and fewer cavities for insulators to fill. Additional savings may result from a reduction in construction waste and dumpster costs.
The advanced framing method combined with continuous wood structural panel sheathing delivers builders with an optimal solution: a cost-effective framing system that will produce more energy efficient homes without compromising he strength or durability of the structure.
Where builders align the vertical framing members under the roof trusses or rafters, a direct load path is created in which compression and tension loads are directly transferred through the vertical framing members. The result is a stronger structure with fewer framing members subject to stresses.
When properly constructed, advanced framed walls that are fully sheathed with wood structural panels provide the structure with the strength to safely withstand design loads. Of all the available wall sheathing products, wood structural panels are afforded the most flexibility within the building code for 24-inch on center wall framing, providing solutions to code limitations that restrict most other wall bracing materials and popular siding products.
Wall bracing solutions: Due to their superior structural performance, continuous sheathing with wood structural panels is code-recognized as wall bracing for studs spaced up to 24 inches on center. Most other wall bracing methods, including let-in bracing and some alternative panel products, are limited by the code to 16-inch on center framing. (Refer to building code requirements or manufacturer ICC-ES reports for more information.)
Siding attachment solutions: The most common and cost-effective grades of vinyl siding require fastening into studs every 16 inches. However, the nailbase capabilities of a continuously sheathed wood structural panel wall allow the use of these siding products with 24-inch on center framing because the sheathing also serves as a base for fastener attachment between studs. This saves the builder the potential added cost and hassle of having to change siding products. (Refer to siding manufacturer ICC-ES reports and APA Technical Topics: Wood Structural Panels Used as Nailable Sheathing, Form TT-109, for more information.)
Wall sheathing systems that incorporate plywood and OSB offer the best balance of energy efficiency, structural performance and affordability. Wood sheathed walls allow for easy integration of windows into the weather resistive barrier and are simple to insulate with all types of cavity insulation for high R-values. Plywood and OSB sheathing also provides shear strength to resist the forces of nature. For more information, refer to APA’s Introduction to Wall Bracing, Form F430.
Wood construction systems such as advanced framing techniques fit well with green building strategies. Wood is a renewable resource that is manufactured in efficient processes that require less energy than is required for other building materials, such as steel and concrete.
Wood-frame construction that utilizes advanced framing techniques delivers even greater environmental dividends by optimizing material usage and reducing construction waste. Many of the construction techniques presented in this guide may be eligible for points under the leading green building standards and guidelines, such as the National Green Building Standard™ (ICC 700-2008) and the U.S. Green Building Council LEED® for Homes Rating System.
The ICC 700, established by the National Association of Home Builders (NAHB) and the International Code Council (ICC) in 2007, awards points to builders that incorporate green practices into single- and multifamily home construction and residential remodeling projects. This includes the implementation of building-code-compliant advanced framing techniques in design and construction. ICC 700 Section 601.2 awards 3 points for each qualifying advanced framing technique implemented that exceeds 80 percent usage in the building, and 9 points maximum if the techniques are used for all floor, wall and/or roof framing. For more information, visit www.nahbgreen.org/NGBS.
Read more about the components of advanced framing.
Get the Details
The Advanced Framing Construction Guide, Form M400, from APA details several techniques for more efficient, cost-effective framing practices, including 2x6 wood framing spaced 24 inches on center, insulated three-stud corners, two-stud corners with ladder blocking, wall intersection options, single headers, single top plates, and eliminating unnecessary materials. Many of these techniques can be adopted independently. The Advanced Framing Construction Guide is now available for free download in PDF format.
Twenty new CAD details, based on the framing techniques featured in the guide, are now available for free download from APACAD.org, APA’s online resource for building designers and construction professionals in search of Computer Aided Design details for wood-frame construction. APACAD.org now features 257 free CAD details, including 30 Spanish-language details, all of which are available to download free of charge in four file formats: DWG, DWF, DXF and PDF.
For more information on the wind resistance of wood structural panel sheathed walls, refer to APA Technical Topics: Wind Resistance of Wood Structural Panel Sheathed Walls, Form TT-110. This publication provides comprehensive information on the wind resistance of light-framed walls sheathed with plywood or OSB using the methodology of the 2012 IBC, Table 2304.6.1 and the 2012 IRC, Table R602.3(3).
Advanced Framing Construction Guide
This free publication from APA details techniques for more efficient, cost-effective framing practices.
Free Advanced Framing CAD Details
Twenty new advanced framing CAD details are now available for free download at APACAD.org.
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