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Can You Use Osb For Roofing

What Makes It Useful

OSB vs. Plywood: Which Should You Choose for Your Roof Deck?

Oriented strand boards are useful for many reasons:

  • The shear strength is dramatically higher than what youd get from plywood.
  • It is easy for an OSB body to appear. The board can feature wood coming from multiple trees and other growths.
  • The design of the board is consistent. The layout features the same strength all around with no noticeable weaknesses all around.
  • Theres no limit as to how large the board can be. Its easier to prepare a customized board that fits your property.
  • It may cost less for you to use such a board versus plywood. The cost varies based on the size of what you use and how well you can get things ready for use.

Using Oriented Strand Board For Shed Walls Floors And Roofs

Using Oriented Strand Board is a tested way of reducing costs for building your shed. Plywood with similar propertiescurrently costs about 30% more for an equivalent thickness.

However, there are some sceptics out there who doubt the strength and durability of OSB. Could it be that these people have inadvertently used the wrong grade of material? Or possibly they haven’t used the right thickness or followed simple guidelines to get the most out of this product.

As with any material there are a few simple rules to follow to ensure that it performs as expected. With OSB there are two aspects to consider. Firstly, purchasing the correct grade of material and then following some simple dimensional rules to maximise the effectiveness of fixings.

Advantages Of Using Osb For Garage Ceiling

There are several advantages to using OSB on your garage ceiling compared to the more commonly used gypsum board or sheetrock.

Firstly, OSB is generally a lighter material, making it easier to install while simultaneously placing less weight on the roofs structure. Because it is made primarily of wood and resin, OSB is extremely easy to attach to the structure above, using only screws to hold it in place.

Because OSB is a tough and durable material, its easily able to withstand the force of most potentially damaging garage activities. Sheetrock, on the other hand, can quite easily become damaged if anything comes into contact with it.

OSB has the advantage of allowing for the installation of shelves, hooks, or any other fasteners at any location on its surface. Sheetrock, on the other hand, requires you to locate the position of the support structure above in order to attach anything to its surface.

Another major advantage of OSB is its significantly reduced cost when compared to other roofing materials. Compared to sheetrock, OSB is around half the price.

When it comes to a need for access to wiring, OSB is easily removable and will not break apart when removed for maintenance to other parts of the house. OSB also tends to have slightly more moisture resistance when compared to other materials.

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The Big Difference Between The Grades Of Board Is The Moisture Resistance Test

In addition to strength tests samples of OSB2 are immersed in water for 24 hours. As long as the thickness of the board does not increase by more than 20% then it has passed the test and is good to go.

The test for OSB3 is more stringent. In the water immersion test it has to swell less than 15%.

A sample of OSB also has to pass a boil test OR a cyclical test.

The boil test is just what it says a sample is immersed in boiling water for a few hours. After which the strengths tests are repeated. I won’t bother you with the details of the strength test except to say that after the above ‘mistreatment’ it must still have just less than 50% of its originaly structural capacities.

The cyclical test takes longer than the boil test. It involves repeatedly soaking a sample of board in water and then drying it in a kiln over a period of three weeks. When the test is finished its remaining strength is checked. The values to be achieved are similar but slightly less onerous than those of the boil test.

Which Is Better 5/8 Or 7/16 For Roof Sheathing

Roofing the right way: What makes OSB panels ideal

5/8-inch paneling is a better choice for roof sheathing than 7/16-inch paneling. This is because of the durability and structural integrity that this additional thickness will bring.

Although 7/16-inch paneling is considered the most common choice for roof sheathing, 5/8-inch roof sheathing is typically one of the best sizes to use when selecting roof sheathing. However, 7/16 paneling is a bare minimum requirement and therefore increased thickness is suggested for heavier builds.

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What Can It Be Used For

Theres a variety of DIY projects that OSB is fantastic for and you can use it for both interior and exterior use as its weather resistant . Its regularly used for flooring because of its strength and its ideal for a workshop or shed. It can also be used for roof sheathing to go under your roofing system or as a sheathing on the walls.

But for a creative person or carpenter OSB can be used to create a multitude of different pieces of furniture or cabinetry as well. With a little creativity the sky is the limit with the endless options, headboards, noticeboards, drawers and wardrobes.

If you are thinking of using it in the garden, although its weather resistant, for permanent outdoor use you will probably want to add some further weather protection. The weather resistant sealant will also only have been applied to the surface of the OSB so as soon as you make a cut into it you will want to add more sealant to ensure that water is not absorbed through the exposed material.

If you are going to add some more water protection, its worth adding some to an offcut of the OSB first to see the effect it has before carrying it out on your whole board. Once youve applied the sealant you can test the offcut by putting some water on it and leaving it for a few hours to see the effect.

Is Osb Acceptable As Roof Decking For Metal Roofing

Oriented Strand Board, commonly referred to as OSB, is a type of engineered lumber similar to particle board, formed by adding adhesives and then compressing layers of wood strands. OSB is widely used as roof decking material.

A homeowner recently wrote and asked me the following regarding OSB roof decking:

Q. We are checking into a metal roof and we have a question that needs to be clarified. We heard that the metal will not stay on as well if you have OSB roof decking. Should it be a different type of wood? Is that true? We have also been told it will be okay. Just wanted some clarification.

Following is my response:

A. OSB in good condition will have every similar fastener pull-out resistance to CDX plywood. The problem, though, is that OSB tends to deteriorate fairly rapidly if exposed to moisture, losing fastener pull-out resistance.

So, what would expose it to moisture? Roof leaks, of course but also improper attic ventilation can cause condensation in the roof deck that can cause the OSB to weaken.

One option is to try some test fasteners in the OSB. If you get 45 or more pounds of pull out resistance, thats considered acceptable for most applications. If you have less than that or a lack of ventilation that threatens ongoing performance, Id replace the decking.

All this said always adhere to what your roofing manufacturer says. Do not do anything that might later void the wind warranty they offer.

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Roof Sheathing Code Requirements

Roof sheathing code requirements vary per state, but the guidelines are the same regarding the quality and ventilation of roofs. Generally, roof sheathing cannot be less than 3/8, and even then, some jurisdictions require thicker wood. Similarly, different projects will require different thicknesses.

To better understand which thickness your project requires, you can reference the APA wood guidelines provided on the roof paneling. Using this stamp and your trusses, you can calculate the right roof sheathing thickness for your new build!

Should I Use Cdx Or Osb For Roofing Plywood

WATCH THIS BEFORE Sheeting Your Roof With OSB!!! (avoid this costly nailing spacing mistake)
  • Roofing
  • Should I use CDX or
  • When planning to redo your roof or repair some damages, you might come across different grades and types of wood, such as OSB and CDX and start wondering what those abbreviations mean. What are the differences? Is one better for roofing than the other? Should I use CDX or OSB for roofing plywood? OSB and CDX do not only look different, but they have unique characteristics that make one better than the other in specific applications.

    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.

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    What Is Better For A Roof Plywood Or Osb

    While watching the builders next door do their thing, I became curious with their technique to install plywood on edges neighboring the next townhouse, and OSB for the rest . What’s the reason to pick one over another?

    Follow up: I’m guessing this is related to OSB’s tendency to expand on the edges when wet, possibly for the flashing and the plywood side of the firewall that would rest on top of this edge of the roof. Here are some links that I came across when doing a bit of research:

    • 1

    Twofold theory:

    Perhaps OSB is cheaper at the moment for this builder than ply and wants to use OSB as much as they can. OSB and Ply are apparently seen as the same in terms of performance and code see:

    However, OSB, when cut, is more susceptible to water damage on the cut . Once OSB edges get wet, it expands like a sponge…which would ruin the roof.

    So, it looks like they might be using as much OSB as they can, but have to switch to ply whenever cutting.

    It could be that they are trying to slow down a fire from spreading. The material at the edges might be more fire resistant, so the fire will spread to adjacent buildings more slowly, allowing the occupants more time to escape. You might be able to verify this by checking the local fire codes for conjoined buildings.

    See how if there was an MS Paint fire, the flames would stay away from the next building .

    Plywood’s Advantage Over Osb

    That, in a nutshell, is the one big advantage plywood holds over OSB. The greater ability a wall has to dry, the more durable it will be, and everyone agrees that more moisture will pass through plywood. This is not a suggestion to never use OSB, but it is a recommendation to factor all the variables and make sure that collectively the components of your wall assembly will not trap moisture inside.

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    Can I Use Screws For Roof Sheathing

    Before discussing nail selection, many roofers often wonder whether you can use screws for roof sheathing. Is it a good alternative to nails?

    The short answer is -yes. Although most roofers prefer nails, screws are almost as effective and more practical in certain projects.

    For instance, screws make more sense for small projects because they offer more control when inserting and extracting. Screws also offer more tensile strength. Tensile strength refers to a materials ability to resist breaking under pressure.

    For instance, you need fasteners with high tensile strength when joining pieces that typically bear weight or come under significant tension once installed.

    So, screws make sense in sheathing since the sheathing material bears significant weight once the roofing sheets are installed.

    Can You Use Osb Board For Roofing Answer Here 2021

    Can You Use OSB Board For Roofing? Answer Here 2021

    Before knowing whether the OSB board can be used for roofing or not, you should have knowledge about the OSB board. So, do you know what the OSB board is?

    Basically, OSB or Oriented Strand Board is formed by compressed layers of the wood strands along with adhesives. Now the question is can you use OSB board for roofing?

    Yes! You can use an OSB board for roofing. In fact, OSB comes with a powerful and protective layout. As a result, nowadays, it has become so popular for roof sheathing.

    We guess you are still confused about making a decision. And, as you havent used an OSB board, its quite normal to be confused.

    Well, to overcome your confusion and turn it into confidence, you have to read our article. Here, we will discuss the use of OSB boards for roofing and why it is so popular.

    So, lets get started

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    What You Need To Know About Roof Sheathing

    Obviously, the surface material of a roof is very important. Whether you choose to install metal, asphalt, tile, fiber cement, wood shakes, etc., the top of your roof is what gives it its aesthetic value and durability characteristics. No matter the material, however, a roof wouldn’t be possible without the sheathing below.

    Roof sheathing provides an area where the surface material can be attached, but it also helps keep the trusses and/or rafters properly spaced. Sheathing is installed over multiple trusses/rafters, so it essentially turns them into one cohesive unit instead of individual structural members. Sheathing works with other components of the roof as well. Ventilation, for example, is needed so that the sheathing doesn’t warp or swell under humid conditions. Felt wrap is installed over the sheathing to create a barrier between it and the bottom of the roofing material above.

    The question that arises is, does sheathing material matter? At first glance it wouldn’t seem so. As long as you are using a durable, substantial 4 x 8-foot sheet of building material, the trusses should have something to keep them together and the roofing material something to fasten to. In actuality however, the perfect sheathing materials are lightweight, dimensionally stable, strong, and affordable. Here’s how some popular sheathing options stack up in those categories.

    Oriented-Strand Board


    Tongue & Groove Boards


    Rigid Foam

    Gypsum Board

    How Osb Is Made

    Logs Debarked: The first step of making OSB is acquiring the logs and debarking them. The bark is later used to create energy for the manufacturing process.

    Cut to strands: The logs are cut into strands of similar sizes. The individual strands of OSB have a size of 1-inch x 6-inches.

    Stands Dried: The Wood strands of OSB are dried in huge tumble dryers to a moisture content of 4% to 8%

    Strands Mixed With Adhesives: Strands are mixed with adhesives that make the strands stick together when pressed. For the inner layer in OSB, Isocyanate or PMDI glue is used. For the outer layers, Melamine-Urea-Formaldehyde or Phenol-Formaldehyde is used.

    Mat Forming: The mix of adhesives and wood strands are formed into thick mats on conveyor belts. The mats are anywhere from 6 to 8 inches thick depending on the wanted thickness of the final board. The mat is separated at intervals and made ready for the press.

    Pressing: Mats are pressed in a large hydraulic press or a continuous press. The illustration above shows a continuous press. The mats are pressed at up to 7500psi of pressure and at degrees of up to 400°F . And a mat will transform in thickness from 6 â 8 inches before pressing to 3/4-inches after being pressed.

    Cooled: Now we have an OSB board. The board is cooled before further processing.

    Sanding: Board is sanded before being sent for sale.

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    For Load Bearing Projects

    Stick to using nails on structural OSB.

    It may take longer to hammer them into place, but the shear strength of nails gives them a big upper hand over screws.

    Plus, if you use a quality nailer tool, you can easily cut that installation time in half.

    Related Post: What Type Of Nailer Should I Use On Plywood?

    What Is Osb For Roofing

    OSB VS PLYWOOD – Which Roofing Deck is Right for You

    OSB stands for oriented strand board, and this versatile building material has been around since the 1970s. Its so popular and cost-effective that it has surpassed plywood as the most commonly used material for sheathing roofs.

    How it is made: OSB is manufactured from fast-growing softwoods that are chipped into thin strands of wood. The strands can be mixed with glue and formed into sheets or with treated wax and resin and then heat treated with high pressure to melt the wax/resin to bond the strands.

    Panel sizes: You can purchase OSB in a variety of thicknesses, starting at ¼ and going all the way up to 1 ¼. The most commonly used thickness of OSB for roofing are 1/2, 5/8 & 3/4. Code for panel thickness varies based on potential snow loads for the area

    One big draw to using OSB is that it comes in a variety of sizes for the panels. Most homeowners use 4×8 or 4×10 foot panels for roofing. Panels are manufactured as large as 4×24, but good luck finding that size or getting the material to your project site.

    Read Also: How Many Screws Per Square For Metal Roofing

    What Is Roof Sheathing

    Roof sheathing is the solid surface below your exterior material, whether its shingles, metal, or another type of covering. It is most often OSB a type of particle board or plywood. In the past, roof substrate was simply dimensional lumber but todays options are cheaper and easier to install.

    The function of sheathing is to provide a smooth, flat, and solid surface for the roofing material to attach to with nails or screws. It also serves as a secondary barrier between your house and the roofing material in keeping water out and heat in, to some extent.

    Sheathing is not meant to be a moisture barrier or vapor barrier primarily. You put underlayment on top of the roof deck to act as a moisture barrier, and your primary vapor barrier will bein your attic, not beneath your shingles or other outer layer.

    The thickness of your roof sheathing is important. Thicker panels will result in a more solid roof deck and resist bowing between the rafters or trusses. Less bowing means a more secure surface for roofing material, improving the longevity of your roof.


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