Tile over wood subfloor. Floating Engineered Wood Floors can simply be installed directly on OSB subfloor.The hardwood flooring must be installed crossing the floor joists (at a 90 degree angle). Your new layer of underlayment needs to be perpendicular to the joists just like the subfloor is. Floor covering (or finish floor) is the term for the topmost, eventual floor--the floor that you walk on and see. Most subfloor-grade plywood uses similar glues between the laminators. There are a few reasons why the actual thickness of plywood varies. Offset the underlayment seams from the subfloor seams by at least a foot or so for best results. Plywood and OSB, O-2 Grade. The bare minimum recommended by most tile setters is a total subfloor thickness of 1-1/8 inch. Most prefer a minimum thickness of at least 1-1/4 inch, such a … The recommended thickness of the plywood subfloor is governed by the spacing of the joists. In this scenario, Jim and Rich install 1/2″ cementious backer unit (CBU) resulting in at least an 1-1/8″ thick subfloor. It creates a bond that goes beyond industry performance standards [2] and is so strong that when used with AdvanTech subflooring as part of an AdvanTech™ Subfloor Assembly , it’s backed by … So what should you do? How many installers turn away the job because the builder refuses to pay for these corrections? In some cases, being a support structure is most important, while in others it is the smoothness, noise insulation or durability. Although 23/32" OSB is span-rated for floor joist systems spaced at 24" on-center, NWFA believes a thicker subfloor is necessary to reduce deflection of the subfloor and minimize pops and squeaks in the wood flooring. Therefore, the NWFA recommendation is to use a 7/8" thick OSB panel for floor systems spaced at 24" on-center. Im trying to hire someone to lay the new subfloor. These numbers indicate the diameter or thickness of the screws. Size and Type of Plywood for Your Shed Floor. NWFA Recommendations OSB stands for oriented strand board. When these issues occur, who's to blame? Improper spacing. Shop AdvanTech 1-1/8-in x 4-ft x 8-ft Tongue and Groove OSB Subfloor in the OSB department at Lowe's.com. Because OSB is made with wood, which will expand or contract when subjected to changes in temperature and relative Because the actual thickness may vary measuring the plywood is the only accurate way to determine its thickness. Make sure it is screwed and fixed at appropriate points, usually a minimum 300mm centres. Subfloor holds up all of the above layers of flooring, as well as everything in your house—people, dogs, cats, pianos, furniture. What Determines Subfloor Thickness The minimum thickness of plywood for subflooring is about 5/8 inch. Oriented Strand Board (OSB) is an engineered wood structural panel created of strands of wood about 1 inch wide and up to 4 feet long. OSB stands for oriented strand board. Maximum Spacing of supports, mm. Miller has more than 21 years of experience in the hardwood flooring industry, most recently having worked as a regional manager at Basic Coatings. The minimum subfloor thickness is approximately 3/4 inches, so the minimum thickness of OSB board you will need for laminate flooring is 23/32 inches, or 18 mm. I'm not concerned with deflection of the joists but I am concerned about the span between joists and deflection under the bath tile. OSB is often used for sheathing in floors and walls, and in some regions, it is the building material of choice. Plywood and OSB manufacturers try to improve this by sealing the panel edges, but the sealant, whether it is a wax or a paint, tends to get scuffed off. When joists are spaced 16-19.2 inches apart, subfloor should be ¾” for both materials. The subfloor is 23/32 T&G OSB, with ¼ inch lauan and sheet vinyl over top. OSB has the appearance of giant cornflakes pressed together to form structural panels in sizes similar to plywood, such as 4' x 8' x 5/8". Introducing "One Thing": A New Video Series. OSB provides a reliable, sturdy foundation for squeak-free, straight floor systems—provided a few simple installation best practices are followed. A 4×8 sheet of plywood is 32 ft 2.. For example, if the area to be covered in plywood is 800 ft 2 then 25 sheets of plywood will be needed to cover it. Even then, it could only be used for outbuildings or workshops. Minimum Thickness, mm. Some experts suggest that 15/32-inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less, but slightly thicker 3/4-inch plywood should be used for joists spaced further apart. Subfloor holds up all of the above layers of flooring, as well as everything in your house—people, dogs, cats, pianos, furniture. 3. Pro performance: 45% less swell and double the internal bond of standard grade OSB T&G Subfloor. If you are a homeowner building your workshop or laying own your subfloor in your house, consider purchasing 5/8" CDX plywood. For joist spans 16 inches or less, NWFA recommends minimum panel thickness of 5⁄8-inch plywood or 23⁄32-inch OSB; the building code requires 5⁄8-inch plywood or OSB. Subfloor holds up all of the above layers of flooring, as well as everything in your house—people, dogs, cats, pianos, furniture. National Wood Flooring Association approves usage of OSB as a subfloor for hardwood flooring with nail-down installation with minimum thickness of 23/32″ and recommended thickness of 7/8″ or 1-1/8″. Several of them have recommended removing portions of the existing floor and replacing it with new plywood. All houses have subfloors. The shortest ones are 1 1/14 inches, while the longest are 3 inches. Tested: APA-certified PS2 for guaranteed consistent standards. Shop AdvanTech 1-1/8-in x 4-ft x 8-ft Tongue and Groove OSB Subfloor in the OSB department at Lowe's.com. AdvanTech subfloor adhesive starts as a foam and settles into a high-strength gel adhesive. Being a wood floor pro—the production manager for Amber Flooring in Emeryville, Calif.—he decided his home ... David Merrill of Spring Grove, Ill.-based Totallywood Flooring tried the Makita 18V X2 (36V) LXT Lithium‑Ion Brushless Cordless 1.6 Gallon HEPA Filter Backpack Dry Vacuum: The thickness needed for subflooring depends on the type of floor that will go on top and the primary purpose for the subfloor. From straight-lay strip to parquet, herringbone and more, these articles offer the 411 on wood floor installation. Standard dimensions are nominal 4 feet by 8 feet. kg lb. Tested: APA-certified PS2 for guaranteed consistent standards. Typically made of plywood or OSB and ranging in thickness from 19/32" to 1 1/8" thick, the subfloor is truly structural, second only to joists in this respect.Subfloor holds up all of the above layers of flooring, as well as everything in your house—people, dogs, cats, pianos, furniture. 9 mm (3) 11 mm (3) 18 mm (5) Width. How to Hire Hardwood Installers and What to Expect. Column 2. The minimum thickness allowed for ceramic tile installations is two sheets of 5/8-inch thick plywood. Serving the Flooring, Woodworking & Moulding Industries Since 1930. Larger OSB Panels Structurally, OSB and plywood are very similar in strength and ability to hold nails or screws; OSB may have greater shear strength -- the ability to span distances -- than comparable thickness of plywood. An OSB subfloor is a subfloor made from oriented strand board (OSB), a manufactured wood product. Divide by the total square footage by the square footage of a sheet of plywood to find the number of sheets required to cover the space. Column 3. Part II – Subfloor Moisture Bringing out the best in hardwood floors. If there is any deflection in the subfloor when walked on it would be advisable to add an additional layer of 3/8" or 1/2" thick plywood underlayment glued and screwed down over the OSB subfloor to add stability. In addition, you’ll find that steel screws come in a number of different lengths. Since it does not hold fasteners as well as plywood, OSB must be a little thicker, or at least 23/32 inch. OSB Thickness for Wall Sheathing. For joist spans 16 inches or less, NWFA recommends minimum panel thickness of 5⁄8-inch plywood or 23⁄32-inch OSB; the building code requires 5⁄8-inch plywood or OSB. When NWFA Guidelines minimums are not met, the recommendations are to overlay the existing subfloor material with a 1⁄2-inch panel product or add structural support from below. Laminate Underlayment: What to Know Before Installation. If the OSB … Using larger OSB panels can be an advantage when flooring a big or odd-size shed, reducing the number of joints in a floor. Brett Miller is the VP of certification and education at the National Wood Flooring Association, where he is responsible for the development, coordination, implementation and presentation of the NWFA’s technical training schools, workshops, and on-line training, as well as the NWFA’s certification program. The thickness of subflooring depends on the spacing of your joists. What Is a Finish Floor or Floor Covering? These numbers indicate the diameter or thickness of the screws. When you’re installing an interior subfloor using 3/4-inch plywood, you’re going to want screws that are labeled #8, #10, or #12. No slip surface: Manufactured with a continuous press, this subfloor does not need to be sanded to meet thickness tolerances. Lee has over two decades of hands-on experience remodeling, fixing, and improving homes, and has been providing home improvement advice for over 12 years. Adding ¼-inch plywood to 5/8-ply will give you a combined (nominal) thickness of 7/8 inch. Meanwhile, OSB compacts as many as 50 layers of strands into a single sheet the same thickness as that plywood, ensuring a much denser—and heavier—product throughout. Simply put, many contractors find OSB to be a more consistent product than plywood or other types of material for subfloor: every sheet is the same. Wood Floor Trick of the Trade: Cutting Carpet Circles Without the Hassle, Wood Floor Trend Spotting: Chevron Blends Modern, Traditional in Athens, https://www.nortonabrasives.com/en-us/markets/floor-sanding?utm_source=Wood%20Floor%20Business, Q&A: Battling Building Code Subfloor Requirements for Wood Floors, Step by Step: Fixing an Uneven Wood Subfloor Before Wood Floors, Pandemic Results in Family Floor of Custom Inlays, Tool Review: Makita LXT Cordless Backpack Dry Vacuum. In this scenario, Jim and Rich install 1/2″ cementious backer unit (CBU) resulting in at least an 1-1/8″ thick subfloor. Item. OSB. Tongue-and-groove edges on many premium floor panels, such as Weyerhaeuser’s Edge Gold ® OSB panels, are designed to self-gap. Very few! Proper acclimatization must be done prior to subfloor installation to achieve stable, long-lasting results. C. Both CD EXPOSURE 1 plywood and OSB Exposure 1 subfloor panels are appropriate subflooring materials, but the proper thickness of the material will be determined by the factors noted below in Part IV – Panel Products Subflooring, E - Acceptable Panel Subfloors. 300 mm (1) 590 mm (1) 606 mm (6) 1200 mm (1) 1220 mm (2) Rated. OSB panels are available in a variety of common thicknesses and sizes as shown in Table 1, below. Column 1. You should not have the sunken flooring issue again. In the end, if the consumer is not happy, someone will be left holding the cards. Check with suppliers to determine availability. Plywood is often sold in 1 / 4 “, 1 / 2 “, or 3 / 4 ” nominal thicknesses, but the actual thickness is often 1 / 32 ” thinner. Oriented Strand Board (OSB) is an engineered wood structural panel created of strands of wood about 1 inch wide and up to 4 feet long. It is not uncommon to see a properly installed floor still exhibit these issues. Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick. But that one hit can quickly turn production income into a nightmare job. Plus, DryGuard comes with a 200-day no-sand warranty. All houses have subfloors. Item. If you have been installing floors over these subflooring systems with success, maybe you don't need to change a thing! Both cost money and time and will likely exceed the traditional installation costs. Blue Ribbon® OSB sheathing panels contain no core voids, knots or splits and provide a quality base layer for wall and roof sheathing applications. Proper acclimatization must be done prior to subfloor installation to achieve stable, long-lasting results. Plywood vs. OSB Subfloor Comparison Guide. This means that a sheet of plywood that started at 3 / 4 ” may shrink slightly after manufacturing.. It’s not just plywood, other types of lumber are smaller than the advertised nominal dimensions for this reason as well. Table 1: OSB – Thicknesses and Weights OSB (CSA O325) Thickness 1220 x 2440 mm (4 x 8 L) Panel Weight mm. Are there any better options available? The bare minimum recommended by most tile setters is a total subfloor thickness of 1-1/8 inch. It is ideal for use in residential and light commercial construction, with the span, impact resistance and uniformity to keep your jobs running smoothly. When NWFA Guidelines minimums are not met, the recommendations are to overlay the existing subfloor material with a 1⁄2-inch panel product or add structural support from below. It’s An OSB sheet has a finely corrugated, unfinished side and a smooth side that is often coated with a clear finish. View Subflooring Suppliers. Laminate, luxury vinyl, and ceramic tile are examples of floor coverings. Why does NWFA have more stringent recommendations than the minimum building code? Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick. OSB Thickness for Wall Sheathing. Tile over Wood Subfloor. Therefore, I'd use 3/4" (23/32) tongue-and-groove OSB, which is standard as a basic single-layer subfloor in new homes. We have laid a new subfloor over the existing subfloor in a couple of mobile homes we’ve worked on. Get daily tips and tricks for making your best home. In contrast, a sheet of engineered OSB is made with up to 50 strand layers packed and compressed into the same thickness with no knots, voids, or imperfections. If they decline to compensate you for the additional work necessary, it is up to you to determine if the work is worth the potential liability. Most subfloor-grade plywood uses similar glues between the laminators. As a wood flooring pro my entire adult life, I've ... Why Would an Existing Wood Floor Cup After Refinishing? But a simple switch to 7/8″ panels offers several advantages for accommodating a home’s energy efficiency and for ensuring the performance of finish materials and the overall feel of the floor. 1,000 square feet in one room straight-laid 31/4, all walls are square and subfloor ... Like many homeowners, when the COVID-19 pandemic hit, Mark Whatley began finding things to update in his home. 1220 mm (4) 1829 mm (3) 2400 mm (1) 2440 mm (3) Depth. Why Some Contractors Like OSB For Subflooring, The Subfloor Is the Foundation of a Good Flooring Installation. Pete Helton Jr. Can You Add Padding Under a Hardwood Floor? The building code for the subfloor is to ensure structural loads are adequate—from a safety perspective, not necessarily from a wood flooring performance perspective. While plywood gives you a more consistent panel, it is still prone to wicking moisture. in. The 3/4 inch thick plywood is sturdy.It can support the weight of a person and heavier equipment without fatiguing over time. But how well suited is OSB for flooring or subflooring? In addition, you’ll find that steel screws come in a number of different lengths. What Is Cement Backer Board and How Is It Used? All houses have subfloors. The minimum subfloor thickness is approximately 3/4 inches, so the minimum thickness of OSB board you will need for laminate flooring is 23/32 inches, or 18 mm. Let’s take a look at what 3/4 inch pressure-treated CDX plywood is and why you want it. OSB has the appearance of giant cornflakes pressed together to form structural panels in sizes similar to plywood, such as 4' x 8' x 5/8". In areas where you want to install vinyl or other flooring requiring a prepared surface, use 3/4" t&g BC plywood to avoid the need for additional underlayment. Put together a plan and cost to achieve what is recommended and present it to the builder/homeowner. Moisture Resistance – OSB … 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: With a limited lifetime warranty and 500-day no-sanding guarantee, AdvanTech® flooring is the flooring panel that more builders trust. A 3 / 4 ” sheet is actually 23 / 32 ” thick. WFB asked its followers on Facebook and Instagram what their fantasy wood floor would be to install. OSB can be used for subfloors, although it is not as common as CDX. Plywood shed flooring is usually 3/4 inch and OSB 5/8 inch thick. However if you are trying to add stability and strength to the subfloor, look at thicknesses from 15 to 22mm. The first step to a warm, comfortable basement floor is to use Barricade or Barricade™ Air Plus: The subfloor panel system that is specifically designed to cover concrete floors. For joist spacing of more than inches up to 19. For 19/32-inch-thick panels, the joists should be 20 inches on center. plywood and OSB are the two most common materials used for floor decking, and typically they are 5/8″ or 3/4″ thick. When NWFA Guidelines minimums are not met, the recommendations are to overlay the existing subfloor material with a 1⁄2-inch panel product or add structural support from below. Re: SUBFLOOR THICKNESS My contractor is using 3/4 AdvanTeck T&G (OSB improved product from Huber Wood), screwed and glued on I-joists @ 19.2 c-c. Sort by: Wickes General Purpose OSB 3 Board - 9mm X 1200mm X 2400mm (391) £17. Not all thickness are readily available. RELATED: Step by Step: Fixing an Uneven Wood Subfloor Before Wood Floors. Careful attention must be paid to the construction and preparation of the subfloor in order to avoid costly callbacks. In this scenario, Jim and Rich install 1/2″ cementious backer unit (CBU) resulting in at least an 1-1/8″ thick subfloor. All houses have subfloors. Do not 1/4 turn the underlayment direction from the subfloor. As long as you are getting thick high-quality plywood or even OSB (anything except MDF / particle board) your home should be fine. Structurally, OSB and plywood are very similar in strength and ability to hold nails or screws; OSB may have greater shear strength -- the ability to span distances -- than comparable thickness … While plywood gives you a more consistent panel, it is still prone to wicking moisture. A beautiful floor starts with a stable subfloor. Most prefer a minimum thickness of at least 1-1/4 inch, such a ¾-inch t&g subfloor with ½ inch plywood underlayment. Typically made of plywood or OSB and ranging in thickness from 19/32" to 1 1/8" thick, the subfloor is truly structural, second only to joists in this respect. I do not see the need to use it throughout the entire home. OSB panels provide an excellent base for many types of finished flooring including ceramic tiles. This high-performance sub-floor is designed to help you avoid costly and time-consuming joint sanding. Minimum Thickness, mm. 5. in. Plywood, or even OSB, has its strength running with its length. How many flooring professionals are confident taking on the liability of adding bracing between the joists to increase the stability of the subflooring system for our wood floor? 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: OSB is generally unsuited as a floor covering: OSB subfloor is mostly serving as a base under the finish floor (hardwood, engineered wood, vinyl tile, etc.) the subfloors need to be thicker. It’s For decades, 23/32″-thick OSB has been the most commonly used thickness of OSB subflooring. ... Thickness. No slip surface: Manufactured with a continuous press, this subfloor does not need to be sanded to meet thickness tolerances. Minimum thickness should be 5/8” for plywood and 23/32” for OSB. OSB Subfloor Panel Edge Sanding Follow Occasionally, oriented strand board (OSB) panels may exhibit thickness swell after being exposed to jobsite moisture/water during project construction. OSB tends to be less expensive than plywood, so builders and contractors can squeeze a bit more profit out of the project. C. Both CD EXPOSURE 1 plywood and OSB Exposure 1 subfloor panels are appropriate subflooring materials, but the proper thickness of the material will be determined by the factors noted below in Part IV – Panel Products Subflooring, E - Acceptable Panel Subfloors. Typically made of plywood or OSB and ranging in thickness from 19/32" to 1 1/8" thick, the subfloor is truly structural, second only to joists in this respect. Plywood and OSB manufacturers try to improve this by sealing the panel edges, but the sealant, whether it is a wax or a paint, tends to get scuffed off. 800 ÷ 32 = 25 sheets When OSB goes beyond flooring use and into wall and roof sheathing, the profit margin will increase. The shortest ones are 1 1/14 inches, while the longest are 3 inches. Filter results Clear all Length. Brett Miller, vice president of certification and education at the National Wood Flooring Association, answers: First, let's get the recommendations straight. Structurally, OSB and plywood are very similar in strength and ability to hold nails or screws; OSB may have greater shear strength -- the ability to span distances -- than comparable thickness of plywood. OSB panels are available in a variety of common thicknesses and sizes as shown in Table 1, below. Minimum Thickness, mm. The recommended minimum thickness of OSB panels for timber-frame walls is 12mm when the cells in the supporting frame measure up to 62.5cm on a side, and 15mm for frame members spaced up … Intended for use on below and slab on grade pads. 18 mm (1) Filter products. With much of today's wood flooring being thinner, wider plank installed on the minimum building code panel thicknesses, we are seeing more creaks, pops and squeaks. An OSB subfloor is a subfloor made from oriented strand board (OSB), a manufactured wood product. First of all, that leaves me with 3k worth of subfloor to sell secondhand. Pro performance: 45% less swell and double the internal bond of standard grade OSB T&G Subfloor. For joist spans 16 inches or less, NWFA recommends minimum panel thickness of 5⁄8-inch plywood or 23⁄32-inch OSB; the building code requires 5⁄8-inch plywood or OSB. Using green joists. An OSB sheet has a finely corrugated, unfinished side and a smooth side that is often coated with a clear finish. The problem is, the builder will still build to the minimum standard, and the issue will arise again. Contractors, builders, and home remodelers have mixed opinions about the use of OSB for flooring, mostly tending toward the negative: A few builders say that they prefer OSB over plywood for flooring because the surface (when new) is always clean, flat, and knot-free. If you’re cutting with a circular saw, set the saw depth to equal the thickness of the OSB subfloor—for example, 0.75 in (1.9 cm). Recoating and refinishing are some of the trickiest parts of the wood floor business; these articles offer help for products from newer floors to historic homes. When you’re installing an interior subfloor using 3/4-inch plywood, you’re going to want screws that are labeled #8, #10, or #12. First, wood shrinks as it dries and moisture leaves the wood. £5.90 per SQM. As with other engineered wood products, OSB comes in a range of thicknesses and styles, and it is important to make sure that the appropriate product is used. Column 3. To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion. OSB: Floor Covering vs. Subfloor Part II – Subfloor Moisture Here's what some of them said: The cost is either shared, or one of the involved parties takes the biggest hit, which can be extremely damaging to any business. Chevron floors have had a recent... Everything from basics on running the big machine to detailed buffer techniques and more are in these wood floor sanding articles. Buy great products from our OSB Category online at Wickes.co.uk. Osb subfloor thickness The thickness of plywood panels in a subfloor is regulated by the. Very few! Plywood and OSB are the two most common materials used for floor decking, and typically they are 5/8″ or 3/4″ thick. DryGuard® enhanced OSB Sturd-I-Floor® is a multi-layered, moisture resistant sub-floor with built-in protection from thickness and edge swell. Love it or despise it, OSB is here to stay. OSB is often used for sheathing in floors and walls, and in some regions, it is the building material of choice. Choose your Product The plywood must be exterior grade for all wet areas and it has to be installed in such a way that the joints between each layer do not line up, using what is known as a … If just overboarding then a minimum 6mm thickness is required. OSB will work as a floor covering only in a pinch. Should You Install Flooring Before You Install Cabinets? Maximum Spacing of supports, mm. National Wood Flooring Association approves usage of OSB as a subfloor for hardwood flooring with nail-down installation with minimum thickness of 23/32″ and recommended thickness of 7/8″ or 1-1/8″. Plywood comes in a variety of thicknesses, beginning at … Cut out squares or rectangles with edges centered over the floor joists below. 2. Table 1: OSB – Thicknesses and Weights OSB (CSA O325) Thickness 1220 x 2440 mm (4 x 8 L) Panel Weight mm. Minimum Thickness, mm. and even below the underlayment, in some cases. This issue's tip is from Daniel Caffo at Daniel Caffo Hardwood Flooring Inc. in Woodlyn, Pa.We... One of the world's oldest cities has a new wood flooring trend. He recommends laying the new subfloor over the existing subfloor, then finishing with the flooring of my choice. Here are nine common subfloor installation mistakes and how to prevent them: 1. Grademark-specified OSB panel thicknesses range from 1/4 inch to 1-1/4 inch. Tile over wood subfloor. There are several factors that determine what subfloor thickness … For joists spaced more than 19.2 inches on center, the minimum thickness for plywood is 7/8 inch and for OSB, 1 inch. The other motivation for builders to use OSB is money. Column 2. See more on this topic: Subfloor/Slab Prep & Underlayment. Column 1. Larger OSB Panels Structurally, OSB and plywood are very similar in strength and ability to hold nails or screws; OSB may have greater shear strength -- the ability to span distances -- than comparable thickness of plywood. As with other engineered wood products, OSB comes in a range of thicknesses and styles, and it is important to make sure that the appropriate product is used. What am I supposed to do? Meanwhile, OSB compacts as many as 50 layers of strands into a single sheet the same thickness as that plywood, ensuring a much denser—and heavier—product throughout. Typically made of plywood or OSB and ranging in thickness from 19/32" to 1 1/8" thick, the subfloor is truly structural, second only to joists in this respect. With joist spacing of over 19.2, thickness of plywood should be 7/8” and of OSB… Planning and patience along with these tips will help ensure that you install the quality of finished flooring you are looking for. With a limited lifetime warranty and 500-day no-sanding guarantee, AdvanTech® flooring is the flooring panel that more builders trust. What is the Actual Thickness of a Sheet of Plywood. The manufacturer, distributor, builder or installer? For joist spacing of more than 16 inches up to 19.2 inches on center, the minimum thickness for both plywood and OSB is 3/4 inch. kg lb. plywood and OSB are the two most common materials used for floor decking, and typically they are 5/8″ or 3/4″ thick. For joist spans 19.2–24 inches, NWFA "Installation Guidelines" recommend a minimum panel thickness of 7⁄8-inch OSB or plywood; the minimum building code (which most builders build to) is 23⁄32-inch OSB or plywood. We supply trade quality DIY and home improvement products at great low prices Plywood and OSB, O-2 Grade.