Fortunately, this is one issue that has primarily been standardized by the industry. When this is the case, experts recommend a 5/8-inch-thick sheet. A special grade of plywood called "CDX" is a popular choice for roof sheathing. The major distinction between these categories is the actual construction of the sheets. Pressure-treated plywood, which is saturated with chemicals to ward off mold, mildew, and insects, can survive outside for decades without paint or a protective finish. It's lightweight but strong and durable - ideal for flooring, walls, and roofing. CDX Plywood: CDX plywood is produced by gluing together sheets of veneer, with each layer being glued the opposite grain to the one below it. The wood is graded on each side from A to D, depending on the level of imperfections, ( A being free of all imperfections and knots and D being un-sanded and considerably defected). In some areas, it is less than half the price of traditional plywood. 2 comments: OSr Group April 14, 2014 at 10:49 PM. Its front has a C-grade while its back has a D-grade. CDX and OSB are used for almost similar things, but because they have different features, one is better applied in some tasks and the other one on other tasks. Differences Between OSB and CDX For Roofing Plywood. Plywood also has a slight advantage in stiffness, which means that subflooring panels need not be quite as thick. Some professionals, however, will use plywood as thin as 1/4 inch for resilient flooring if the subfloor is in particularly good condition. CDX; This option is basically a specialized plywood grade. CDX is veneer plywood. Before you can really grasp the different ways to use CDX plywood vs. OSB, it can help to have a better understanding of what each of them is. As a result, OSB floors are more … Many homes have rafters that are even wider at 24 inches apart and will require a thicker sheet of plywood. Both CDX plywood and OSB tend to come in standard sheets of four-foot by eight-foot (4×8). The wood is extremely durable, which makes it an ideal material to be used in a roofing base. For a decking, or substrate underneath shingles, you can usually use either material. Contractors often prefer to use OSB because of the significant cost savings that it can bring. Correction to this wood product problem can clean your wallet. No, the "X" in CDX plywood … The higher the slope, the more quickly the snow and rain will be shed, but also the greater the wind force. The APA would recognize CDX Grade Plywood as C-D Exposure 1 plywood. X signifies the glue that bonds the veneers. Uses. CDX plywood is a construction-grade type of plywood that is designed for exposure to the elements. CDX plywood has one side veneer grade “C” and one side veneer grade “D”. With 24-inch truss/joist spacing, the National Wood Flooring Association recommends 1-inch OSB underlayment, compared to 7/8-inch plywood. CDX plywood is often used under shingles and roofing felt, on walls (just behind the siding and insulation), and as a sub floor just under the carpet pad or a tiled floor's durock. Plywood. CDX is the grade of plywood most commonly used for roofing. Plywood gets it strength from multiple layers of wood bonded together. Contractors often prefer to use OSB because of the significant cost savings that it can bring. The two are bonded together with glue which can withstand a little moisture. Timber & Sheet. Press Esc to cancel. Roof decking is the material that lies on top of the main roofing structure, and the underlayment and roof covering are applied on top. In some areas, it is less than half the price of traditional plywood. Specializing in building and renovating homes, Thomas Luttrell has worked in homebuilding since 2002. The roof of your house covers and protects everything inside of those walls from the rain, snow, and sleet that come your way. The letter “X” in CDX refers to the type of glue used in the factory to bond the plywood veneers. Depending on thickness, plywood is also approximately two pounds or more lighter per sheet. Because of its construction, some manufacturers actually make larger sheets of OSB. CDX plywood is durable and moisture proof. CDX stands for "C-D Exposure 1 plywood" . Given that the edges may swell with exposure to moisture, you may prefer to use these larger panels to minimize the number of edges along the roof. A flatter roof with rafters farther apart may need a thickness of up to ¾ inch. A roof that lays practically flat will have a much heavier load than a steeper roof that allows rain, snow, and ice to roll right off. In roofing, plywood can be used as roof decking. This is a popular option because it presents homeowners with functional but affordable roof sheathing. This comes as a surprise to many consumers because OSB looks simply as if lots of pieces of wood were glued together. The roof is perhaps the most important part of your entire home. In this case, plywood should be a minimum of 3/8 inch thick. Radiant barrier plywood is most often used for roofing. Email This BlogThis! Manufactured by sticking together sheets of veneer, CDX plywood is also a popular choice. The edges may also swell during this time, creating small yet visible ridges on the roof where the boards meet. The letters A, B, C and D typically refer to the veneer or face of the material. The alternating grain gives the plywood a system of checks and balances that allow it to expand and contract evenly across the sheet. Connect With Us . The roof deck is the surface underneath your roof and roofing underlayment. Plywood is graded per side, meaning that individual sides can be graded differently. ... CDX is the most common form of plywood, with a C-grade side and D-grade side, and the X stands for the glue that bonds the sheets together. If you need a crash course in selecting the right plywood, this guide should make things a little easier. What is CDX Plywood vs. OSB? CDX plywood is created by bundling layers of wood together. This means that OSD is the perfect choice for applications such as exterior wall sheathing and roofing. Moisture Differences. It adds proven performance and durability to … CDX Plywood. A final mark to check is the thickness of the plywood. In such places, it does not get in contact with a lot of moisture, which prevents it from getting damaged. Most construction sites will consider the use of either OSB or plywood for the roof. Type above and press Enter to search. Most underlayment-approved plywood is at least 11/32 inches, the standard recommendation. While CDX is strong and will give good results, it is important that you take care of it. The outcome is a wooden sheet that is relatively as solid as steel, without the weight that comes along with steel or cement. Another issue that many people encounter is what size plywood the roof may need. Some mistakenly think the “X” stands for “exterior”—which is not true. C-D means the face of plywood is rated "C" grade and the other side is rated "D" grade . In fact, recent price quotes from Denver, Boston and Atlanta put 7/16-inch osb $3.00 to as much as $5.00 per sheet lower than 1/2-inch cdx plywood. This variety of plywood is designed to be very durable in the face of both physical wear and rain damage. It determines how long your roof will last and how well it will protect the contents of your home. The grading system for plywood is an easy puzzle to solve thanks to the simple A–D letter system used to indicate the quality of the panel. The most common scenario is a home that has rafters set approximately 16 inches apart. When it comes to choosing what kind of plywood you need for the roof, it is important to understand the basic categories that you can choose from. Like most other things, there is no one right answer for the plywood thickness of your roof. CDX Plywood is used primarily by contractors to build exterior walls and roofs. C & D grades. Be sure to weigh the advantages and disadvantages of each option before you decide which way to go for your new home or your updated roof. The wood grain alternates from layer to layer, adding significantly to the strength of the plywood sheet. This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer. One of the most important factors when selecting the plywood for your roof is how thick each piece should be. CDX Plywood. The main difference between the two is how they handle moisture, and oddly enough there are wildly varying conclusions - from very reputable sources - as to just how vapour permeable they are. I would argue that plywood isn’t used for roofing, but for decking the roof prior to installing the actual roofing material. Posted by Scott B at 9:35 PM. As a result of this strength, CDX plywood … OSB is best for … This type of plywood grade is a good choice for projects where you will ultimately conceal the plywood panel with some other type of cover material. Cover it on both occasions and maintain it regularly to ensure it does not get damaged. Save my name, email, and website in this browser for the next time I comment. Comes in standard 4-by-8-foot sheets, is strong, durable, and relatively light. Keep in mind that the load of the roof still plays a role in the plywood thickness. It is usually made of 4′ by 8′ sheets that should be 1/2″ thick. Water Boil Proof (WBP)- Ideal uses Flooring, Roofing, Shuttering. CDX plywood sizes are typically available in sizes 3, 5, 7, and 9, and there are a variety of thicknesses available, ranging from 1/4 inch to … What is OSB? Roofers often favor using plywood because of its ease of installation and natural strength, though more durable options may be necessary in areas that are prone to frequent thunderstorms. CDX plywood is commonly used in the construction industry for the foundation and roofing of buildings. Read, be informed, and extract maximum useful life from your plywood project. Should you use CDX (plywood) or OSB (oriented strand board) for roofing plywood? The two are bonded together with glue which can withstand a little moisture. Choosing the right type of plywood for the roof is one of the most important construction decisions that you will have to make. However, when it is penetrated by water, it takes a very long time to finally dry out compared to CDX plywood. The answer depends mostly on how far apart the rafters are and the roof loads, which vary based on the pitch of your roof. Plywood is stronger. Rafters that are slightly farther apart might require ½ inch or 5/8-inch-thick plywood. CDX Plywood is used primarily by contractors to build exterior walls and roofs. 23/32 in. The good news is that CDX plywood is available at most home and garden stores, since it is a common material used for home DIY and construction projects. Specifications ; Georgia Pacific 1/2" x 4 ... Width 4' (1220 mm) Sign Up for Updates. If plywood is not dealt with properly, it can swell and create major problems with roofing, flooring or siding. Here is another option for plywood you might think about: RTD Plywood: Everything You Need to Know. Building codes recognize both plywood and OSB to be alike in their properties and use the phrase \"wood structural panel\" to describe them.However, plywood subfloors are stiffer than OSB by about 10%. Even though plywood is more expensive, and OSB stronger, my recommendation for a shed roof is 5/8” or 3/4″ construction-grade exterior rated (CDX) T&G plywood. He also holds a bachelor's degree in English from Iowa University. Connect With Us. Get the latest news, tips, tools and product updates for all your roofing projects. Roofs are framed with rafters or trusses, which are rafters joined by internal braces so they install as a single component. 1/2" x 4' x 8' 4-Ply CDX Plywood Item #: 271066 Manufacturer #: PLY 1/2. As construction and industrial plywood, CDX plywood is usually used as wall sheathing, roofing and so on . However, you may need to consider bolstering the plywood thickness for a roof that has a higher load. Both OSB and plywood for the roof have been approved for use, so it may come down to what you feel most comfortable using. What is CDX? However, you might find that OSB can better suit your needs than plywood for the roof. It also holds roofing nails well. CDX plywood is used as flooring materials, wall sheathing, roofing ply . Both plywood and oriented strand board (OSB) are equal in strength and durability. They can range from the standard 4’ x 8’ piece to a 4’ x 9’ or even a 4’ x 10’. Building & Roofing. Now, let’s have a look at some of the main differences between CDX and OSB as roofing plywood. - FSC certified. Plywood also has a slight advantage in stiffness, which means that subflooring panels do not need to be as thick. The letter "X" means the glue of the plywood is exterior glue . For instance, with 24-inch truss/joist spacings, the National Wood Flooring Association recommends nominal 1 inch OSB underlayment compared to 7/8 inch CDX plywood. Understanding the different types of plywood for the roof, the thicknesses, and the common sizes can help you to make wiser decisions for your home. Email Address Sign Up. You want to make sure that you are building a quality roof that will last you for decades to come, but you need the right kind of plywood for the roof. The letter “X” stands for exposure, which means the plywood is tough enough to withstand a little moisture—but for only a short time. - Water Boil Proof (WBP) - Ideal uses Flooring, Roofing, Shuttering. At the end of the day, what kind of plywood should you use for your roof? The highest quality—and most expensive—types of plywood are the A & B grades. CDX is best for sub-flooring. It's easy to install and can be cut to the size you need at home. Buy on Beacon Pro+ . These tips cover plywood characteristics and proper installation of plywood. It is made of multiple layers of thinly cut, solid sheets of wood that are pressed together. OSB and plywood offer similar (and sufficient) performance in terms of strength and functionality, though plywood is about 7% stronger. The result is a wooden sheet that is Much larger panels that measure up to 8’ x 24’ could also be available from specialty retailers. The APA would recognize CDX Grade Plywood as C-D Exposure 1 plywood. It is extremely resistant to moisture. It can withstand moisture for a brief period of time but may become warped and delaminated with consistent exposure to the elements. CDX plywood has one side veneer grade “C” and one side veneer grade “D”. The Minimum Plywood for Roofing. Although it's easy to find at your local home center, it's probably not the best choice for smaller projects, like a bookshelf or other furniture around the house. Going back to the X in CDX, you may recall that it means ‘exposure.’ The more economical types of plywood are the High quality CDX sheathing manufactured from soft spruce wood. Eventually, the panel must be covered by something more weather resistant—like bricks, siding or shingles. Share to Twitter Share to Facebook Share to Pinterest. It is also used for roof sheathing. As a quick primer in plywood, each side is rated from A to D. A is smooth and knot-free while D, the lowest quality, has missing knots and cracks. What kind of plywood is used for roofing? Both CDX plywood and OSB have advantages and disadvantages when it comes to plywood for roofing. This price spread means that a builder can save $700.00 on a 2,500 square foot house if osb is substituted for plywood sheathing on floors, walls, and roofs. OSB is a cheap imitation of CDX. Alternatively, OSB is created from wood chips, resin, and adhesive that is baked and formed into the shape of a sheet of plywood. Combustible Wood Deck UL Class A Assemblies. The common grade of plywood for roof sheathing is CDX. WBP Structural Grade CE2+ Plywood Sheets. One of the major differences between OSB and CDX plywood is how well each holds up against water. If it comes down to OSB or plywood for the roof, which one should you choose? At the end of the day, what kind of plywood should you use for your roof? Both CDX plywood and OSB have advantages and disadvantages when it comes to plywood for roofing. A half inch CDX plywood is often used with rafter with 24-inch spacing. Be careful not to confuse the words “outdoor,” “exterior,” and “pressure treated” to all mean the same thing. x 4 ft. x 8 ft. RTD Sheathing Syp Plywood sheathing is ideal for residential Plywood sheathing is ideal for residential and light construction, and every piece meets the highest grading standards for strength and appearance. plywood. 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