first, i would just go with cdx but i just started college so money is a bit tight, anyway my room is small (still living with my parents) and im thinking about putting a floor in my attic to give my self some more room. ACX, CDX, and BB Formply are the most common types of plywood sold. When it dries, it is more likely to return to its … One of the main grading systems when talking about the plywood is the smoothness of its front and back sides. OSB holds up to water quite well, and it is easily seen as water-proof. It is made of wood chips, resin and glue, cast and baked together to produce a CDX-like sheet. Plywood is often sold in 1 / 4 “, 1 / 2 “, or 3 / 4 ” nominal thicknesses, but the actual thickness is often 1 / 32 ” thinner. CDX plywood. Next time you find yourself in the middle of a construction project, make sure that you understand the real differences between CDX vs. OSB plywood. While OSB can pack 50 strand layers into a sheet, plywood only has 5-7, giving OSB a more consistent density, though it does about two pounds or so more per sheet then plywood. Although, OSB typically offers a higher shear rating which adds rigidity to your structure. Both oriented strand board (OSB) and plywood are considered the same by building codes. However, you will want the finished veneer of CDX for projects like cabinets and furniture. My personal opinion is that OSB performs well on the wall and floor but stick to CDX Plywood on the roof. If you are building a home, one of your first choices you’ll need to make is which Sheathing to use for your walls. Which is the better option, plywood vs. Advantech? Determining how well they can hold up to water also determines what types of applications each one is best suited for. 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. If you continue to use this site we will assume that you are happy with it. Plywood is composed of approximately 92% - 97% wood, with the remainder made up by primers, sealants, and adhesives such as phenol formaldehyde resin. However, it needs to be covered and protected long-term. A: Clayton DeKorne, chief editor of JLC, responds: VOC emissions are pretty much a nonissue for exterior-grade plywood and OSB. The sheets are generally 4 x 8 or 4 x 12 feet in size. This won’t imply the actual quality of wood itself, e.g. One of the nice things about plywood is the variety of options you can buy. 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. 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%. The ‘best is classified by the least knots, shown grain, etc. Alternatively, OSB tends to be more waterproof than traditional plywood. Plywood is made with an odd number of layers for optimal strength and performance. By Clayton DeKorne Download the PDF version of this article. Trubord 7/16 is rated 24/16 and 15/32 and 1/2 are rated 32/16. 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. On page 6 is OSB Sheathing info and a 24/16 L/180 has a uniform load of 68 at 24″o.c. Some design and construction professionals have come to swear by oriented strand board. Plywood vs. OSB (Oriented Strand Board): Major Differences . OSB and plywood offer similar (and sufficient) performance in terms of strength and functionality, though plywood is about 7% stronger. Sherwood Lumber uses cookies to ensure that we give you the best experience on our website. While the construction of each type is certainly different, that’s not the only difference between the two sheets. Others, however, prefer to stick with plywood. What’s a roofdeck? than CDX plywood. Secondly, OSB panels have a higher shear rating than plywood panels and are thus often installed with greater spans than plywood of the same thickness. A 3 / 4 ” sheet is actually 23 / 32 ” thick. Are there any roofing situations where osb should NOT be used? While you may want to consider a different type of roof sheathing, CDX plywood is still not a great choice for your roof. While some people do prefer to go with traditional plywood, many construction experts make the argument that OSB is better for roofing. Melville, NY 11747, Terms & Conditions As a result, OSB floors are more li… The edges of the boards may swell and cause ridges on the roof beneath the shingles. COPORATE HEADQUARTERS This costs money and time, but knowing the difference between OSB and CDX does not. But, as we have seen each one of them has its strengths and weaknesses, making each one of them, best for different tasks. Press Esc to cancel. As mentioned above, the X in CDX stands for exposure. At the end of the day, you should only really use CDX plywood for interior applications or surfaces that will not see much water. CDX vs OSB sheeting. Save my name, email, and website in this browser for the next time I comment. However, there is one area of concern in which plywood beats OSB. Each of these materials has its own unique properties and qualities, and so each is used in specific applications. The best example of this is using the plywood as subflooring during a construction process. Should you use CDX (plywood) or OSB (oriented strand board) for roofing plywood? It is often less expensive than CDX plywood because this manufacturing process doesn’t require the same costly veneers found on the front and back of CDX plywood. The National Roofing Contractors Association, the Asphalt Roofing Manufacturers Association. This can result in visible deflection of the panels between the supports and can telegraph through causing a wavy appearance to the roof. OSB is much more waterproof than plywood and CDX plywood. OSB is now used for about 70 percent of all floor, wall and roof sheathing in North America. Oriented strand board (OSB) combines wood chips, glue, and resin into the shape of a sheet of plywood and bakes them together. Because the actual thickness may vary measuring the plywood is the only accurate way to determine its thickness. Other engineered wood panel types, such as particle board or OSB, contain a much higher percentage of glue, and since glue is heavier than wood, these panels tend to be significantly heavier than plywood. OSB, on the other hand, stands for Oriented Strand Board which is a cheaper version of CDX. Structure or Basic Composition. Type above and press Enter to search. Moisture resistance ... with less glue than plywood. Not to mention, you don’t necessarily need to pay the veneer that you will get with the CDX grade of plywood. Many of these abbreviations that you hear will represent different types of plywood that are used for subflooring, roofing, and everything in between. OSB and plywood vary in terms of durability. This makes its dimensional stability better. Specializing in building and renovating homes, Thomas Luttrell has worked in homebuilding since 2002. OSB holds up to water quite well, and it is easily seen as water-proof. In 2001, oriented strand board surpassed plywood in terms of square footage produced. While plywood is generally limited to 8 to 10 feet lengths, OSB panels can be manufactured in lengths up to 16 feet. But take care, it also requires that you use water-resistant coating at the edges. Depending on your location, you might find that it is roughly half the price of more traditional CDX plywood. To get more informed insight on which one to use for what, you can always ask an expert. What is the difference between CDX and OSB? You will need to remove everything and start all over or ask a specialist to correct the mistake. Is Rain on a Steel Roof Louder than on an Asphalt Roof? But, there is an exception to pressure-treated CDX; they can withstand extreme moisture without getting water damaged. Unlike OSB, plywood has been developed into different types over the years in different ways to be used for different purposes. The result is a wooden sheet that is proportionally as strong as steel, without the weight that comes along with concrete or steel. At the end of the day, you should only really use CDX plywood for interior applications or surfaces that will not see much water. The biggest difference is how both react when exposed to large amounts of moisture over an extended period of time. It is also used for roof sheathing. For example: Marine plywood is more moisture resistant than standard plywood, is better used in constructions where exposure to water is likely (e.g. If you have to choose, you need to know the difference between CDX vs. OSB. Even as affordable as they are, well-reputable stores like Sherwood Lumber still offer insane deals and discounts. The major distinction between these categories is the actual construction of the sheets. VOCs in Plywood vs OSB. Since it will never be visible, it may just be a waste of money. But, there is an exception to pressure-treated CDX; they can withstand extreme moisture without getting water damaged. In the case of CDX plywood, the X at the end denotes that it is rated for exposure. Even after losing the water, it will take time for it to go back to its original state. What is the Actual Thickness of a Sheet of Plywood. When choosing a new roof, don’t forget to consider what surface the roof will nailed onto. Should they go with OSB vs. CDX plywood for the roof? I recommend that all roofdecks, especially in moist climates like Seattle, are CDX plywood and not OSB. Up until 2000, plywood held the majority of the market for wall, roof, and floor sheathing when it was surpassed by OSB, which as of 2018, held about 75% of the market share. Making the right choice is easy when you understand the inherent differences between these starkly distinctive types of materials! Within 10 … CDX plywood is produced by gluing together sheets of veneer, with each layer being glued the opposite grain to the one below it. OSB is best for substrate underneath shingles or decking. 225 Broadhollow Rd.Suite 310W The protection of the shingles isn’t likely to be enough to prevent the plywood from becoming warped and delaminated over time. If you are not among the people searching for such answers, then you should be because it is important to know what the two are and their differences. Even though CDX is not waterproof and absorbs water easily, it also loses this water quickly and goes back to its original shape. If you are asking why knowing their differences is so important, here is why. This is because the glue and resin used in its processing prevent it from absorbing water even during the extremely humid a… On the other hand, OSB is produced very differently. The letters C and D represent the grades of either side of the plywood, while X stands for exposure. ACX and CDX are both exterior plywoods and aren’t specifying the type of wood. Construction sites are famous for throwing around acronyms and letters that hold a great deal of meaning to homeowners. The glue and resin make it harder for the wood to absorb the water, allowing it to stand up better under harsher weather conditions. Alternatively, OSB tends to be more waterproof than traditional plywood. OSB absorbs water more slowly than plywood, which can be beneficial in areas of low dampness. Both plywood and oriented strand board (OSB) are equal in strength and durability. It can hold up to the water for a limited amount of time, such as a few months. Because plywood is rated as shop grade because of defects, almost any type of plywood can end up in the shop grade bin. This comes as a surprise to many consumers because OSB looks simply as if lots of pieces of wood were glued together. Despite these disadvantages, OSB is still commonly used for roofing. While CDX is strong and will give good results, it is important that you take care of it. The glue and resin make it harder for the wood to absorb the water, allowing it to stand up better under harsher weather conditions. CDX plywood is created by bundling layers of wood together. Well, when used as exposed decking or subflooring each has its strengths and weaknesses. CDX is best for sub-flooring. The National Roofing Contractors Association and the Asphalt Roofing Manufacturers Association both gave the thumbs-up of approval to use OSB for roof sheathing, provided that each sheet has approval from the APA – Engineered Wood Association. Far too often I see OSB “sag” between the trusses making your roof look wavy. Now that we both agree that knowing the difference between the two is important, let’s start by knowing what they really are. 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