Most OSB suppliers have a load/span table giving a guide to the spacing of timbers for different thicknesses. A staple in a wide range of construction projects, OSB board is used for everything for sheeting through to structural sheathing and more. An exception to this standard, however, may occur if you intend to install slate, concrete or tile shingles on your roof. Thickness or Rating (1) The thickness or rating of roof sheathing on a flat roof used as a walking deck shall conform to either Table 9.23.14.5.A. Todd Miller has spent his entire career in the metal building products manufacturing industry. We heard that the metal will not stay on as well if you have OSB roof decking. I have some sample two-square rolls of a good synthetic and would be happy to send you one or two if you pay the freight from Ohio. See Store Availability. Another issue that many people encounter is what size plywood the roof may need. Todd Miller 8510 Industry Park Drive Piqua, OH 45356 (937) 773-9840 ©2009 – 2020 AskToddMiller.com Site Maintained by StoryRidge Marketing. OSB roof panels should always be installed with the grade stamp facing into the attic and the screened surface (with the nail guide lines) facing up. These are plywood and OSB (oriented strand board) boards commonly used for sheathing walls, roofs, and decks. 9mm, 11mm or 18mm. plywood. Top. Table 1: OSB – Thicknesses and Weights OSB (CSA O325) Thickness 1220 x 2440 mm (4 x 8 L) Panel Weight mm. OSB panels … It is a great choice for your roof, using clips. I've never used commodity OSB on a roof but it's probably fine in 5/8" thickness, and possibly in 1/2" thickness. for pricing and availability. Refine Results Plywood and OSB - 100. done clear all. It has better structural integrity than plywood, it's less expensive, and contemporary products are just as able to repel rain and moisture. View Profile View Forum Posts Private Message View Articles Super Moderator Join Date Sep 2002 Posts 7,451. If you absolutely must use different thickness sheathing, replace all of the plywood above the one that needs to be replaced (to the ridge of the roof). How To Install Osb Sheathing Installation Instructions Guide Roof8 Tips For Getting The Best Out Of Your Oriented Strand Board OsbWhat Thickness Osb To Use […] This basically calculates the number of sheets needed for a Gable roof. Post by The Z'eer » Tue Feb 20, 2018 7:10 pm. kg lb. Originally, plywood was the go-to choice for roof decking. The thickness required by Josh’s circumstances are good for roof snow loads of up to 70 psf (again spanning 24”). 18mm was initially chosen for its strength. OSB is so strong in fact that it is now used for about 70% of all floor, wall and roof sheathing in North America and there are two different types of OSB, OSB2 and OSB3. Both plywood and oriented strand board (OSB) are equal in strength and durability. I’m replacing some knackered 10mm ish T&G that’s had a rought time under some felt with holes in. Sheathing should be a minimum of 19/32-inch thick. Or do i insulate and board then offer fascias up and cut to the tops of the boardis, GookieMonster, Oct 26, 2017 #1. 23/32 CAT PS2-10 OSB Sheathing, Application as 4 x 8. My shed is OSB, with a layer of torch on roof felt, been good for 10 years. Exterior grade plywood and OSB are the two main choices for roofing. Not Available for Delivery . or Table 9.23.15.7.B. The thickness of OSB is controlled the same way plywood is. Compare; Find My Store . Oriented Strand Board (OSB) OSB is a type of wood panel comprising of timber strands and should be manufactured in accordance with BS EN 300: Part 3: 1992. Plywood with similar properties currently costs about 30% more for an equivalent thickness. OSB Boards used for the deck should be: a minimum thickness of 18mm (these will be able to span up to 600mm). Popularity—which is used more? Showing 7 of 7 products . For shed construction there are two commonly used grades of OSB… The choice of Plywood should be exterior grade per British Standard (BS) 5268-2, WBP (Water & Boil Proof) to BS EN 636-2:1997. It's a waste of money and resources. Dimensions include: OSB board 18mm; OSB board 11mm. The nails should be spaced 6 inches around the edges of a sheet and 12 inches in the middle. How to Install Cement Backerboard for Flooring, University of Massachusetts - Amherst: Choosing Between Oriented Strandboard and Plywood, OSB Guide: When It Comes to Roof Sheathing, OSB Has You Covered. Is OSB Acceptable as Roof Decking for Metal Roofing? OSB has its advantages. Panel thickness will also affect permeability - using the 2 perm variable of 7/16ths OSB sheathing, at 3/4" thickness the permeability drops to 2/3rds of a perm. Oriented Strand Board isn't plywood, nor is it a type of particleboard, fiberboard or wafer board, and although it is a newcomer to a plywood-dominated market, its use for exterior sheathing is becoming routine. Thickness: a minimum 18mm is usually recommended. Using OSB. Re: Plywood Thickness for 24" OC Rafters Plywood is really a thing of the past. Our house currently has 7/16 inch OSB on it. It’s the standard for spacing of 24 inches in the rafter, although as mentioned, a 5/8 inch thick is more ideal. OSB are preferred for non-heavy tiling. By saturating the strands with wax before gluing them together, manufacturers give OSB an ability to repel water that is equal to or better than that of plywood. Out of Stock Online . That, in a nutshell, is the one big advantage plywood holds over OSB. Alaska to be specific. In other words, you don't want to have 3/8" above the 1/2" because it will create a ridge that water will settle in. Both types of reconstituted wood panels come in different sizes and thicknesses. OSB is widely used as roof decking material. Lets learn the differences between CDX and OSB so you can make a more informed decision when it comes time to choose one or the other for your roofing project. Or just have a look at the table below. 99 / box. We are checking into a metal roof and we have a question that needs to be clarified. OSB is so strong in fact that it is now used for about 70% of all floor, wall and roof sheathing in North America and there are two different types of OSB, OSB2 and OSB3. Thickness or Rating (1) The thickness or rating of roof sheathing on a flat roof used as a walking deck shall conform to either Table 9.23.14.5.A. Standard roof sheathing, which consists of 4-by-8 sheets of plywood or oriented strand board, or OSB, is 1/2-inch thick and attaches directly to the roof rafters or the roof trusses. R. Re: What thickness of plywood for shed roof...? Insulfloor 4 Pack 15.5 inch x 48 inch x 1 inch ThermoSmart Subfloor Panel (1) $49. The calculation is based on that the Plywood or OSB (Oriented Strand Board) sheets are of a 4' x 8' size. Plywood's Advantage over OSB? The thickness of OSB that you need varies on where it is used in a building. 8 Tips For Getting The Best Out Of Your Oriented Strand Board Osb. Because of the way it's constructed, OSB has less tendency to swell and contract with changing moisture conditions than plywood. 92. Trubord. If you get 45 or more pounds of pull out resistance, that’s considered acceptable for most applications. Home | Roofing Information | Is OSB Acceptable as Roof Decking for Metal Roofing? Reply. OSB is now used for about 70 percent of all floor, wall and roof sheathing in North America. In the U.S., roof sheathing is almost always composed of wood—usually OSB (oriented strand board) or plywood. If you're looking for OSB board for roofing, or for most other purposes, we've got what you need at discount price, ready for fast dispatch across the UK. Use the thickest OSB panels for load-bearing applications such as floor decking and roofing. So, does it matter on the what timber sheets I use to board the roof. A half inch thickness is considered to be standard in a lot of areas and it should work just fine considering that it’s deemed okay by the roofing contractor after considering the things above. Sterling board is resistant to water, with the OSB3 option being particularly suitable for humid conditions. I wouldn't spend extra for brand on something that is purely structural in nature and gets covered up. The resistance of OSB to rot depends on the material from which it is made. Is that true? One sheet = 32 ft² . One sheet = 32 ft². As a result, OSB floors are more li… View Details. OSB panels are one of the most commonly used products for creating subfloor underlays. Get help with your home improvement projects. for subfloors. OSB2 is great for structural, non-load bearing projects in dry conditions whereas OSB3 performs better for structural, load bearing use and for use in humid conditions. We have also been told it will be okay. The Z'eer Newly registered Member Posts: 87 Joined: Fri Sep 08, 2017 11:37 am Has thanked: 35 times Been thanked: 1 time. kg lb. Should I use felt between osb and tin. OSB comes in 4-by-8-foot sheets, as does plywood, but the manufacturing process allows the production of longer and wider ones. The Ontario Building Code | Thickness or Rating 9.23.15.7. Model #776391180002. Osb Thickness For Roof. Sheets must have a 1/8-inch expansion gap between them and should be secured to the rafters with 8d nails. Should it be a different type of wood? Typically 3/4"(18mm) for floors and 3/8" (9mm) for walls and 1/2" (11mm) roof. double nailed at each joist. CDX works fine in 1/2" or 5/8" thickness. Both CDX plywood and OSB tend to come in standard sheets of four-foot by eight-foot (4×8). 11. sam_underhill. A half inch thickness is considered to be standard in a lot of areas and it should work just fine considering that it’s deemed okay by the roofing contractor after considering the things above. “One, it’s more common than plywood,” he points out. A good alternative to ply-wood and usually cheaper, we stock OSB3 board in a selection of sizes. This gives OSB more shear strength than plywood, and it has virtually no tendency to delaminate. or Table 9.23.15.7.B. Extension will be 8ft wide by 11ft long, it will be a lean to sort of extnsion so only 3 sides and a roof needed. Your email address will not be published. To be fair, OSB is not exactly best friends with water either. Always pay attention to the thickness of the boards, and work accordingly with your materials. Sounds like a great project! double nailed at each joist. This comes as a surprise to many consumers because OSB looks simply as if lots of pieces of wood were glued together. OSB Boards used for the deck should be: a minimum thickness of 18mm (these will be able to span up to 600mm). As a landscape builder, he helped establish two gardening companies. It’s simply “the lesser of two evils,” according to Lipinskiy. If you have less than that or a lack of ventilation that threatens ongoing performance, I’d replace the decking. Save Share. My main concern was sheathing thickness, but will take in all anyone can offer. I am a home owner operating as GC, while using Contractors to build a two-story 30×30 addition over a poured concrete basement. Both the National Roofing Contractors Association and the Asphalt Roofing Manufacturers Association recommend the use of OSB for roof sheathing, as long as it bears the approval stamp of the APA - Engineered Wood Association. OSB panel products give engineers, designers, specifiers and builders a broad array of choices for use as subfloors, combination floors, wall and roof sheathing. When it comes to using OSB or plywood for gussets, Vogt says that OSB is more commonly used. The only downfall when comparing the two materials is cost. laid with staggered joints. It banned OSB after Hurricane Andrew caused extensive damage to rooftops in 1992, citing OSB's inferior ability to hold nails. Learn how your comment data is processed. Dazzchazz New Member. Tom can help. Half-inch OSB is suitable for rafter spacings up to 24 inches, whether or not the edges are supported. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. I know some places it's 7/16, others 1/2" or 5/8" January 21st, 2010, 01:15 PM #2. Moisture causes the edges to swell more than the centers, and this can produce noticeable ridges under thin roof coverings such as asphalt tiles. Item #70213. Learn more about what you want and what you need in a new roof, before you invite the contractor into your home. We have the right sized OSB3 board for almost every job. Could a cover the boards with a tarp after boarding for a few weeks to a month before I felt/fiberglass it? Wgoodrich. TIMBER BOARDING (PLANKING) Item #12215. Oriented strand board (OSB) Made up of multiple layers of wood strands compressed at odd angles to each other and bound with water-resistant adhesives. The oriented strand board (OSB)—This board type of layers and strands of wood, adhered together to form a board. We are going to replace the shingles, and my father-in-law (who lives in Minnesota) says that we should have 5/8 inch. The square footage of a Hip roof area is identical to the square footage of a Gable roof of the same measurements. Not all decking is the same. 101 months. However, OSB is generally considered less resistant to water (it swells in thickness when exposed to moisture) and some people prefer plywood for roofs and subfloors. Standard roof sheathing, which consists of 4-by-8 sheets of plywood or oriented strand board, or OSB, is 1/2-inch thick and attaches directly to the roof rafters or the roof trusses. April 3, 2017 | Filed under: Metal Roofing, Roofing Answers, Roofing Installation, Roofing Materials. 9.5 3/8 18 40 11 7/16 21 46 12 15/32 23 50 15 19/32 29 63 18 23/32 34 76 22 7/8 42 92 28.5 1-1/8 54 120 Notes: However, you might find that OSB can better suit your needs than plywood for the roof. When the grade stamp is covered by roofing, the building inspector will not be able to confirm that the correct OSB roofing panel was used. Both OSB and plywood absolutely hate water, Lipinskiy mentions, going on to say that the most important part, regardless of which decking option you choose, is that all penetration points on a roof … Alaska to be specific. Estimate the amount of plywood or OSB needed for sheathing a roof. View Details. OSB panels often have lines at 16- and 24-in. white boards . Building codes, the Engineered Wood Association, architects and most builders rate plywood and oriented strand board (OBS sheathing) equal in strength and durability. OSB sold in the UK is made to comply with BS EN 300 Oriented Strand Board (OSB) Definitions, Classifications and Specifications. Sheets made from aspen or poplar, which are common, have more rot susceptibility than those made from rot-resistant species. The more wood chips there are, the thicker the OSB will be. Todd is currently Vice President of the MRA (Metal Roofing Association) and a Past Chair of MCA (Metal Construction Association). OSB panels are available in a variety of common thicknesses and sizes as shown in Table 1, below. If you get 45 or more pounds of pull out resistance, that’s considered acceptable for most applications. brown boards. Both OSB and plywood absolutely hate water, Lipinskiy mentions, going on to say that the most important part, regardless of which decking option you choose, is that all penetration points on a roof are sealed. OSB comes in 4-by-8-foot sheets, as does plywood, but the manufacturing process allows the production of longer and wider ones. The Ontario Building Code | Thickness or Rating 9.23.15.7. The typical thickness range for sheathing is 3/8 to 3/4 inch. Just about to build an extension to my shed. Sheathing 3/8 CAT PS2-10 OSB Sheathing, Application as 4 x 8. 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