Wood framing (type V construction) is one of the most common building typologies especially in the residential construction industry. Most homes in the U.S. use wood framing for the primary structure. In many cases this means 2x4 or 2x6 studs at 16 inches on center with batt insulation between and plywood sheathing on the exterior. This blog explores some different wood frame technologies and methods you may find beneficial for your next project.
Advanced Wood Framing
Advanced wood framing is a technique for optimizing energy efficiency and reducing construction waste by increasing thermal resistance and being more strategic about stud placement. This is achieved by the following:
1. 24 inch stud spacing - Each stud acts as a thermal bridge (area in a wall less energy efficient than the insulation) between the exterior and interior. When increasing the stud spacing we reduce the number of thermal bridges and increase the energy efficiency. The more commonly utilized 16 inch spacing in a stud wall is generally overkill for the structural requirements. The 16 inch spacing allows the framing contractor to place a stud wherever they want without aligning the ceiling joist and other structural elements. In advanced framing we are optimizing the structure and therefore more care must be taken to get the correct alignments with other structural elements. The studs, ceiling joists, and rafters must all align to transfer the structural loads effectively to the foundation.
2. Engineered Headers and Single King Studs – In traditional framing the headers above the windows and doors are typically packed full of lumber and normally are not necessary. Advanced framing uses engineered headers to provide structural optimization. The headers are also placed in line with the outside face of the stud to allow a space for insulation between the header and the interior finish. In addition to engineered headers advanced framing also uses one king stud on each side of the opening and header hangers to transfer the structural load into it. This reduces even more lumber usage.
3. Ladder Blocked Tee Corners– Traditional framing uses tee studs to tie interior walls to exterior ones. These use a large amount of lumber and provide little if any insulation in these locations. The Ladder block approach both reduces the lumber and allows space for insulation.
4. Engineering Stud Size – In advanced frame construction 2x6 studs are used on lower floors while 2x4 studs are used on upper floors. A structural engineer can help you determine where this change can occur. This reduces lumber cost and material while optimizing structure.
Cross Laminated Timber
Another wood frame technology you probably haven't heard of is CLT or Cross Laminated Timber. CLT is a pre-fabricated wood panel that is extremely strong and fire resistant. CLT can be used to create long spans with thin profiles and produces very little waste given that it is constructed in a factory setting much like a wood truss. These wood panels can be used on walls, floors, and roofs and in many instances can serve as the exterior and interior finish in addition to providing the structure. CLT is at the front lines of the architecture industry where architects all over the world are using it to create wooden skyscrapers. The product is extremely simple and truly amazing.
Structural Insulated Panels
Structural Insulated Panels (SIPS) like CLT are created in a factory to meet the plans and specs. Once created they are then shipped to the site for assembly. SIPS are created by sandwiching rigid foam between two layers of plywood. SIPS offer an extraordinary amount of thermal resistance and can be assembled in far less time than traditional methods. The energy efficiency is achieved mostly through the extreme reduction in thermal bridging that studs create in traditional framing methods. Although SIPS are more expensive up front, the cost savings in labor and energy bills is remarkable and will ultimately cost you far less.
T-Studs
T-studs are essentially small trusses oriented vertically inside the walls. The space between the outer rail and the inner rail is filled with spray foam giving the wall some extreme thermal resistance, virtually eliminating the thermal bridges all together. Although this product is used more in colder climates its thermal resistance benefits could make a great impact here as well. The cost of the framing is said to be not much higher than 2x6 framing and the methods of construction are almost identical to standard stud framing.
Standard wood framing methods have been around for a long time. With advances in technology there are new and inventive wood framing methods that are proving to be far superior. We encourage all of our clients to consider alternative construction technologies to help their homes perform and save money long term. Let us know if you're interested to know more about different wood frame technologies.
© 2019 by Clements Wimsatt Architects PLLC
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