The required minimum spacing of the fastener being used is determined using the diaphragm shear load or diaphragm capacity per unit length of the connection. Fasteners should be driven flush with the panel surface. This will require careful layout of the decking placement (in new construction) or careful layout of panels (in existing construction). Plank decking is often used where the appearance of the decking is desired as an architectural feature or where the fire performance must meet the heavy timber construction requirements outlined in Part 3 of the National Building Code of Canada. Some roof problems could stem from panels installed over wet decking. This process takes the original wood chips and condenses them into solid sheets. A common method of increasing diaphragm capacities in this condition is to install a layer of wood structural panels (WSP)i.e., plywood or OSBon top of the lumber decking. All Rights Reserved, Douglas fir (D.Fir-L species combination), Pacific coast hemlock (Hem-Fir species combination), Various species of spruce, pine and fir (S-P-F species combination), Western red cedar (Northern species combination). Plywood panels are manufactured by gluing together three or more cross-laminated wood layers. Individual planks can span simply between supports, but are generally random lengths spanning several supports for economy and to take advantage of increased stiffness. We use cookies on this site to enhance your user experience. This typically happens when there are strong winds and other weather conditions. In this condition, the lumber decking is no longer used as the structural diaphragm; the WSP layer is attached to the lumber decking and acts as a blocked diaphragm, using the capacities in SDPWS Table 4.2A. The Michigan Statewide Carpenters and Millwrights Joint Apprentice and Training From 1 story to 18, were here to support the success of your commercial and multi-family wood building projects with one-on-one project assistance. The only thing different is the choice of thickness you use with each. Our customer support team will get back to you as soon as possible. Plank decking is available in two grades: Select grade has a higher quality appearance and is also stronger and stiffer than commercial grade. The panels should be spaced 1/8-inch apart at the ends and edges. Your question and USGs answer may be posted to this page in the future, but none of your personal info will be included. The only downfall when comparing the two materials is cost. Input the volume of structural wood in a building, and our Carbon Calculator will estimate how much carbon is stored in the wood. A general design rule for controlled random plank decking is that spans should not be more than 600 mm (2 ft) longer than the length which 40 percent of the decking shipment exceeds. Although plywood is traditionally used to create the roof deck, its becoming more popular for contractors to use OSB. CSA S-6 Canadian Highway Bridge Design Code, Wood design in the National Building Code of Canada, Design Values for Canadian Species used in Canada, 2022 Canadian Wood Council. Decking can be ordered in specific lengths, but limited availability and extra costs should be expected. Call our technical support team at 800.USG.4YOU (874.4968). It usually isnt an issue if they get slightly wet from rainwhen given the correct amount of time to dry. Another consideration is whether minimum nail penetration values into the decking can be met. Both the latter methods of installation require planks of predetermined length and a consequently there could be an associated cost premium. OSB panels are made from multiple layers of wood flakes oriented 90 degrees to each other. At these locations, the diaphragm forces need to be taken out of the sheathing, through the decking, potentially into the boundary framing members (depending on how the floor/roof is framed) and then into the vertical lateral force-resisting systems below. During the installation of OSB, the rough surface side should be facing up.
Click the link in the email to create a new password. As this may not meet the minimum nail penetration of SDPWS Table 4.2A, discussion with the building official may be prudent.
The attachment of the decking to the diaphragm boundary framing members (or directly to the vertical lateral force-resisting system) is designed for the unit diaphragm reaction along that line, or the chord force, whichever is greater. The first number is the maximum span for roof sheathing, assuming that the panels are installed with the long dimension across three or more supports, with the edges supported. If youre a contractor, this is no news to you. Design and detailing considerations for designers seeking to increase the diaphragm capacity of lumber decking systems. Rafters should be straight and in alignment during the installation of sheathing. Learn about wood products and make a new contact to facilitate material fulfillment for your next project. Overtime, plywood has shown experience to dry much quicker than OSB. Please check your email. Terms & Conditions Privacy Policy, Designing and Building with Mass Timber: Design, Planning and Performance, Mid-Rise Design: Optimizing Size, Framing Efficiently with Engineered Wood, Protective Design in Mass Timber Construction, Nominate your project for a 2023 Wood Design Award, Tall Wood Corner with Ricky McLain | June 2022, New Installer Training Programs: Gearing Up the Workforce for Mass Timber Construction, Calculating the Carbon Stored in Wood Products, Introduction to Whole Building Life Cycle Assessment: The Basics, When to Include Biogenic Carbon in an LCA. 2022 WoodWorks All Rights Reserved. The fasteners should be spaced only 4 inches apart on the panel edge at the gable end wall framing. Questions should relate to this product specifically. Nails and deck spikes are used to fasten adjacent pieces of plank decking to one another and are also used to fasten the deck to its supports. Since plank decking is not grade stamped like dimensional lumber, verification of the grade should be obtained in writing from the supplier or a qualified grading agency should be retained to check the supplied material. Nominations now open for the 2023 Wood Design Awards. Discover the most recent award-winning wood designs demonstrating attributes of strength, beauty, versatility, cost effectiveness, and sustainability. and provides certification to help you stand out from the crowd. These sheets of wood may look similar, but they are not created the same. No matter what you choose, both materials are top of the line and complete the job! When designing wood-frame structures with lumber floor and roof decking, either new construction or modifications and rehabilitations of existing construction, the diaphragm capacity or aspect ratio of the lumber decking system may be inadequate and require reinforcing measures. SDPWS Sections 4.2.7.1 and 4.2.7.1.1 provide specific requirements when using the WSP over lumber decking diaphragm condition. When OSB gets wet, it will swell over time. Oriented standard board (OSB) is created much differently. InterNACHI can help you get licensed in your state or province, The label on the far left is a common rating label for sheathing installed on roof trusses spaced 24 inches on center, which is widely recognized as an economical construction method for residential roofs. For further information, visit the APA - Engineered Wood Association's website at www.apawood.org. Lumber roof sheathing and lumber roof panels are terms used in the International Residential Code that refer to panels manufactured with fully waterproof adhesive. Ideal as an alternative to plywood, metal decking and concrete, this panel won't buckle, warp or create moisture issues for the roof system.
We can help you find the most appropriate wood solution. Stay up-to-date on industry news, innovative projects, and more. Plank decking can be used in either wet or dry service conditions and can be treated with preservatives, dependent on the wood species. To minimize shrinkage and warping, plank decking consists of sawn lumber members that are dried to a moisture content of 19 percent or less at the time of surfacing (S-Dry). The thicker the material is, the less likely the nails will pull out of the panels. Consider us an extension of your team. Lumber decking, particularly when perpendicular to the supports, is a much more flexible diaphragm system than WSP diaphragms and does not effectively share load with the WSP diaphragm. Roof decking is the layer between your metal roofing panels and the structural elements of your roof. High-performance structural panel and the only one UL Certified for noncombusibility Structural Panel Concrete Roof Deck is a noncombustible, durable structural panel with great uplift ratings. This usually isnt a fault in the roof and decking installation. All homes can take quite the beating over the years by Mother Nature! This report suggests that only 1.0 of penetration is required for 8d nails to achieve full diaphragm capacity. Always pay attention to the thickness of the boards, and work accordingly with your materials. Plank decking is most readily available in random lengths of 1.8 to 6.1 m (6 to 20 ft). This component is essential in both metal roofing and traditional asphalt shingle roofing. High-performance structural panel and the only one UL Certified for noncombusibility Structural Panel Concrete Roof Deck is a noncombustible, durable structural panel with great uplift ratings. The minimum thickness of lumber roof sheathing should conform to Table 1 below.
Plywood is less likely to take as long to dry in these circumstances. APA Report TT-097provides a summary of considerations andAPA Report TT-061provides information for the condition of inadequate nail penetration. It looks like you entered an employee email address, but this is the customer sign-in. Please enter the email address you used to create the account. Wind & Hail Roof Inspection and Replacement. A typical specification for random lengths could require that at least 90 percent of the plank decking be 3.0 m (10 ft) and longer, and at least 40 percent be 4.9 m (16 ft) and longer.
This interactive resource includes up-to-date information on topics from mass timber products and design best practices to taller wood construction and sustainability. Installing Metal Roof Panels Over Shingles. However, no roof is 100% perfect! The 38 mm (1-1/2 in) decking has a single tongue and groove while the thicker sizes have a double tongue and groove. The more wood chips there are, the thicker the OSB will be. Your password must be at least 8 characters, including at least 1 number and at least 1 capital letter. Not all decking is the same. Sheathing provides the base for attaching the roof covering and adds strength to the framed structure. Blocking can help correct areas with twisted framing, as well as provide surface for the panels. Now That Youve Had a Home Inspection book. The contractor can choose an oriented standard board (OSB) or plywood to create the decking of the roof. Estimate the wood carbon footprint of your project. Brock Commons, University of British Columbia Case Study, Ensemble Acoustical Drywall Ceiling Estimator, New Products: USG Ceilings Inspirational Book, Danoline Acoustical Gypsum Inspirational Book, Terms and Conditions for CGC Sales/Terms and Conditions for CGC POs, Toxic Reduction Act Public Report Hagersville Plant, Strong, durable concrete panel; great uplift ratings, Dimensionally stable; panel will not buckle or warp like wood sheathing; no moisture issues like traditional concrete decks, Installs fast and easy: circular saw for cutting; screws for fastening, Meets the criteria of ASTM E136-12 for use in all types of noncombustible construction. It is common for framing supports, such as roof trusses, to be spaced 24 inches on center. Field fasteners attach the sheathing to the decking to keep panels from buckling out of plane. The dense woodchips compressed together will take longer to dry if they become wet. Use the link below instead. Of course, you dont want either of these decking materials to become saturated. The material is strong, durable, and tested over time. Originally, plywood was the go-to choice for roof decking. Well get back to you as quickly as we can. The capacities of lumber diaphragms are given in Table 4.2D of the American Wood Councils Special Design Provisions for Wind and Seismic (SDPWS). The standard sizes and profiles are shown below.
Quadruple your inspection business and reduce your liability with the Additional options to evaluate the seismic capacity of existing lumber decking can be found in ASCE 41-13. The rating appears as two numbers.
locations and where the roof is specially engineered. After hearing the pros and cons of each material, would you use plywood or OSB for your decking? Wood structural panels should be attached to the framing in accordance with the following table. OSB is heavier than plywood, and its typically stronger as well. The panels should be installed over two or more spans, with the long dimension or strength axis oriented across the rafter boards or truss cords. There are characteristic differences between the two materials. If you take a look at a sheet of OSB, youll notice the surface isnt extremely smooth. There should be at least 3/8-inch of space between the fastener and the panel edge. The thickness of the plywood can be controlled by the number of plies glued together. Decking is generally available in the following species: In order to product plank decking, sawn lumber is milled into a tongue and groove profile with special surface machining, such as a V-joint. For example, if the lumber decking is only 1x (3/4 actual thickness) or 2x (1-1/2 actual thickness), nails used to attach the WSP to the decking may only be 1-1/2 long, meaning the minimum nail penetration of SDPWS Table 4.2A may not be able to be met.
You never know what Mother Nature will bring to the Midwest, so its extremely important to make sure your decking material is completely dry at all costs! For common installations, the panels are fastened with 8 d common or deformed shank As noted, the diaphragm capacity of the decking is not usedonly that of the blocked diaphragm consisting of the sheathing laid on top. Designed to carry gravity and lateral loads, this dimensionally stable roof deck is mechanically fastened to cold-formed steel joists or framing members, and roof membranes or insulation attach directly over the panels, making installation fast and easy.