In the pursuit of the infamous structural engineer T.Y. Lin’s powerful statement “To engineers who , rather than blindly following the codes of practice, seek to apply the laws of nature” I have always been interested in the subject of advanced framing techniques. The basic premise of advanced framing techniques is “a system of construction framing techniques designed to optimize building materials to produce wood-framed buildings with lower material and labor costs than conventional framed structures. Builders who utilize advanced framing techniques optimize framing material usage, reduce wood waste and, with effective insulation detailing, boost the building’s efficiency to meet today’s energy code requirements. When properly designed and constructed, advanced framed walls that are fully sheathed with wood structural panels, such as plywood or oriented strand board (OSB), provide the structural strength necessary to safely withstand the forces of nature.” (APA The Engineered Wood Association).
For professionals who have experience in structural steel and reinforced concrete framing systems, the definition of “advanced framing” will sound very similar to what has been the standard practice in steel and concrete for decades. The reason this practice is titled “advanced” in the wood industry is due to the wide use of prescriptive design, which has never been prevalent in the steel and concrete industries. It is my belief that the development of the prescriptive design in the International Residential Code has caused the wood framing industry to largely lag behind its counterparts in terms of material and labor efficiency. With the availability of software programs that can readily analyze wood framed structures I think it is time for the wood industry to re-evaluate the widespread use of prescriptive designs and utilize advanced framing techniques to elevate wood framing up to par with concrete and steel framing techniques.
I recently had the opportunity to put advanced framing techniques to the test with my own personal residence. My wife and I designed our 2,800 SF ranch house on our 10 acre property in Montgomery, Texas. For the framing, I designed all of the exterior walls to be 2×6 studs @ 24” O.C. The material savings came out to approximately 30% compared to traditional 2×4 stud walls @ 16” O.C. Other advanced framing techniques that were utilized included:
floor joists and rafters spaced @ 24” O.C. which took advantage of the the subfloor and roof deck’s inherent ability to span distance greater than 16” and reduced the total number of pieces.
Insulated exterior headers which reduced thermal bridging with little detriment to the structural capacity.
Blocking and straps at shear walls utilizing the “Force Transfer Around Openings” analysis approach that reduced the total length of shear walls required.
In the end, the framer was able to successfully implement the design as intended. Besides the material savings, the advanced framing techniques also provide additional benefits such as a larger cavity space for insulation in the exterior walls and less thermal bridging due to the reduced number of pieces in the exterior wall. I consider this implementation of advanced framing a success and look forward to its use on future projects.