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Plywood Sheathing – What Is It And Why Use It

Numerous steps in the building process, like installing new flooring and performing other structural modifications, need choosing a sheathing selection. Plywood sheathing is widely recommended for use in construction, even for something as straightforward as a shed. You must first be familiar with it before deciding whether or not to pursue it.

Sheathing a surface in plywood prevents heat loss and internal damage. When used for support, it is thin and strong, but when used to moderate temperature, it thickens and becomes pliable. Sheathing plywood does not adhere to any sort of industry standard.

Read on to find more about the two distinct kinds of plywood sheathing, as well as some of the benefits and drawbacks of each. The post’s conclusion will help you decide if plywood is necessary for your sheathing project. In addition, you’ll have a better idea of what kind of plywood to purchase and how to avoid common pitfalls. To begin, though, we’ll examine the two primary categories of sheathing used in building.

Typical plywood sheathing used on exterior walls before cladding

Sheathing: A Brief Overview

Putting something between two surfaces protects them from each other. The term “sheathing” can also be applied to the material that is utilized in this process. Plywood, OSB, gypsum board, cement board, and glass mat are all used as structural sheathing in construction.

It follows that the sheath connecting Surfaces A and B must be sturdy if they are. It is important that Surface B doesn’t take the full force of a blow on Surface A. Impact protection is provided by structural sheathing.

Sheathing can seem unnecessary if surfaces A and B are rarely damaged. Sheathing may not be crucial for structural integrity, but it is necessary to prevent brittleness in any case.

Framing in Myrtle Beach, South Carolina by @MBFramingLLC
Sheathing a building with plywood has two purposes: it prevents water damage by acting as a moisture barrier and it reinforces the frame by providing a shear surface.
Myrtle Beach, South Carolina, framing, plywood, OSB, framing, framing Fridays, construction https://t.co/1LLu7N8U5s https://t.co/1bKdomFh8Z
1:26 PM · Jan 17, 2020
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The insulation used for temperature control is often rather thick, which prevents heat from escaping via any gaps in the sheathing. If you put some thick plywood between the outside and inside of a wall, the sun’s heat won’t be able to penetrate the room as quickly. Similar to how artificial heating inside the room will not quickly escape by direct conduction during the winter months.

Structural sheathing is prioritized over insulating sheathing. This is due to the fact that insulation coating can be applied over sheathing to provide additional insulation. As a result, I shall shorten “structural sheathing plywood” to “plywood sheathing” for the rest of this entry. While a temperature controlling layer isn’t usually an inherent part of the building, structural sheathing often serves that purpose.

View a video demonstration of proper wall sheathing installation here:

The Georgia-Pacific Approach to Wall Sheathing Installation
Demonstration of sheathing interior walls on video

Is Sheathing the Same as Plywood?

It’s important to note that sheathing and plywood sheathing are not synonymous. Sheathing is a substance used to insulate and protect the walls from damage. There are various sheathing options besides plywood, but plywood is the most common.

You can expand your options and increase the likelihood of making a good decision by realizing that plywood sheathing isn’t your only choice. The most common types of wall sheathing are plywood and OSB. Plywood isn’t technically sheathing, but it doesn’t stop people from using it for that purpose. The plywood used for sheathing is often thicker. It’s multilayered design is supposed to provide more insulation.

Plywood sheathing is acceptable in the areas listed below, whereas those that are not are not.

Location/Aspect

OSB Floors and Roof Sheathing Are Recommendations

Beams framed in plywood sheathing Plywood sheathing

Walls lined with plywood

OSB Sheathing Table: When to Use It and When Not to

Is Sheathing Plywood Waterproof?

The plywood used for sheathing is not waterproof, but marine-grade plywood is nearly impervious to water. The plywood can be protected from moisture by being varnished with waterproofing agent, but the sheathing is unnecessary because it will be covered over.

This holds true even in places where there is a lot of moisture, such as the walls of a kitchen or bathroom. The exposed surface, not the insulation in between, should bear the brunt of waterproofing efforts.

https://twitter.com/SchwabStrong/status/1390114614797500416?s=20&t=2Ga FQpXIAgMak0Wr-hHSg

Can You Use Sheathing Plywood Outside?

Plywood sheathing can be used in the outdoors, but it must be properly waterproofed before being installed. Unlike furniture plywood, structural plywood is not treated, so it will deteriorate quickly in damp environments.

Plasterboard can be protected from water with Rust-Oleum Urethane Water Based Finish. This finish can be used on exposed wood even though it is water-based. Plywood used for sheathing is already resistant to water, so if it can waterproof exposed wood, it can do the same for plywood.

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We will start installing the overhead door tomorrow, and the FRP plywood and plastic wall sheathing will be finished by then. Tags: #ShopBuild #SoWhiteInHere https://t.co/iz39IFujX2
6:08 PM · Mar 14, 2019 16 \s0
Plywood sheathing can be covered entirely, or just the sheathing that will be visible in the kitchen and bathroom. Is there a need for this? But only if the sheathing is never exposed. However, it is still a good option for the material that will be used to cover the plywood sheathing.

If you have any leftover finish from waterproofing plywood, you can use it to give your furniture a new shine and prevent yellowing. The product has over 1,200 reviews and ratings that average a 4.5-star rating on a 5-star scale. Given that 87% of buyers rated it four or five stars, it’s safe to say you won’t be disappointed.

This finish is designed for use on publicly visible surfaces, as it resists fading over time. It may be excessive to use it on something that few people actually notice. However, this finish should only be chosen if it is financially feasible. As opposed to standard waterproof plywood, this option is more affordable.

How Strong Is Sheathing Plywood?

Plywood used for sheathing can withstand 22 lbf/ft2 of weight. Some plywood types can support up to 164 pounds. You can choose a sheathing material based on its thickness (and consequent strength) or on how well it fits into your design.

Plywood with a thickness of 3/8 inches is adequate for wall sheathing but cannot withstand significant impact. Plywood with a thickness of 1 inch would be too thick for this application despite its ability to sustain virtually any form of impact. Plywood sheathing with a thickness of 3/8 inch is the industry standard because it provides adequate insulation while still being relatively flexible.

Be sure to read my piece, “Everything Plywood,” which is a wealth of information about plywood densities and strengths.

Plywood is quite hard, so if your sheathing can withstand more pressure than the surface, the latter will crack. Consider the price tag as well. Currently, the price of plywood exceeds that of OSB of the same width.

Options for Sheathing a Frame (and Their Prices): OSB, Plywood, ZIP, and ZIP-R
A video demonstrating the versatility and durability of plywood sheathing.
Plywood sheathing might be one of the more expensive options for walls, especially if you choose with a broader plank and must pay to have it waterproofed. Based on my observations, the benefits it provides are not sufficient to warrant the price.

Roofing by Achten’s Roofing @AchtensRoofing
This task is ideal for demonstrating how the roofing process progresses.
First, we’ll be replacing the plywood sheathing.
Phase 2: Underlayment Application
Third, we install shingles on top of everything. If you have any questions about our roofing systems, feel free to give us a call at 1-800-ROOFTOP. https://t.co/qqydr9pkvZ
2:00 PM · Jun 20, 2022
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What Types of Plywood Are Used for Sheathing?

For sheathing, we utilize softwood plywood because too much stiffness will crack the overlay. The plywood comes from several trees, such as spruce, cedar, fir, redwood, and pine. Plywood derived from softwood and at least 3/8 of an inch thick can be used for wall sheathing.

Hardwood plywood, on the other hand, is superior for sheathing beams and pressure-bearing sections because to its greater durability, which results in superior impact insulation and support. This is reflected in the fact that hardwood sources are rarely used in the regularly used sheathing plywood choices. However, this may be because hardwood plywood is less typical.

Modular Construction at an Affordable Price! @Econofab
This 12′ x 30′ x 12′ pole building has an enclosed lean-too that is 10’x20’x8′ and has a steeped roof at the main building, as well as an overhead door that is 10’x10′, slider windows that are 6’x3′ and 3’x3′, a walk-in door, an overhang of 18″, and sheathing made from 1/2″ cdx plywood. https://t.co/yOTZ5stDGS
12:56 PM · Oct 14, 2021 0 \s0
However, it is still a good idea to verify the plywood’s composition. The aforementioned softwoods and waterproof adhesives are your best bets.

Plywood Sheathing vs. Plywood

Wooden Sheathing and Plywood Plywood and other similar materials are related but not the same. Using regular plywood for insulation and thinking of it as sheathing plywood is the most common blunder.

Plywood planks can serve as an ineffective sheath, at best. However, in the worst-case scenario, the walls would collapse due to the impact and the lack of insulation provided by the hard, thin plywood sheets.

The absence of any discernible insulation is by far the most typical result. Wall sheathing isn’t there to provide structural insulation because walls are rarely struck. It’s possible to use substandard plywood and still have sturdy, crack-free walls.

The Southampton Building – SH Building Corp.
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12:10 PM · Mar 10, 2014 0 \s0
On the other hand, if the plywood utilized isn’t thick enough, it won’t do anything to stop the flow of heat through the walls.

If you understand what makes plywood a good sheathing material, you can prevent this oversight. Some things to keep in mind are as follows.

Plywood used for sheathing is substantial without being overwhelmingly so; plywood that is too thin won’t provide enough insulation for the walls. A material’s price and malleability can go up if it’s too thick.
Plywood sheathing should be flexible so that it can absorb impact without damaging the overlying material.
Using plywood for wall sheathing is a cost-effective option; however, if the price of the plywood seems unusually high, you should look elsewhere. Plywood with a veneer overlay and manufactured from exotic hardwoods is more expensive. As a sheathing material, it is the worst possible choice.
We just have plywood sheathing, which is unfinished. Plywood sheathing isn’t waterproof, so if it will be exposed to water in any way, shape, or form, you need coat it with waterproof varnish.

What Is Plywood Sheathing Used For?

Plywood sheathing is preferred over wall sheathing for load-bearing components such as flooring and beams because of its structural endurance and ability to more effectively insulate these components from the elements. OSB sheathing, on the other hand, is optimal for use in wall heat insulation and cannot be employed for this purpose.

One common misconception is that OSB and plywood can be used in place of one another in sheathing. As a result of its lower price per square foot, OSB is frequently chosen as wall sheathing instead of plywood.

@aschroofing John Asch
We found many rotten rafters, some pine rake, and some plywood sheathing. Before putting on a new low-pitch roof on this Parlin, Elm Terrace home, we replaced any and all rotten wood. Our warranty is the longest in the industry for low-slope roofs. Roof repair for a low-pitched roof. https://t.co/NFn6gDvYu5
6:34 PM · Jan 26, 2021 0 \s0
It still cannot be utilized in places where plywood underlayment is required. OSB isn’t sturdy enough for use as floor or beam sheathing. On top of that, OSB is useless for anything requiring bracing or framing. In both cases, plywood is a superior material.

Both oriented strand board (OSB) and plywood are commonly used as sheathing materials, therefore the misconception that they are equivalent persists. Sheathing, on the other hand, is a two-pronged endeavor. It can be installed to make a building last longer or to make sure it doesn’t get too hot or cold.

Contrast OSB with plywood, which is entirely different. See my article for a detailed explanation of the advantages of each option for use in an attic or under a floor.

Compared to other types of plywood, OSB is not as strong due to its thick fibers/flakes. Even a sturdy board can be broken with enough force from a single blow. However, OSB is much more manageable due of its thickness, which prevents heat transfer. Similar thicknesses of plywood are available, albeit at a higher price. The added cost of plywood sheathing is not justified if the surface will not be struck regularly.

However, in any situation where OSB would be appropriate as sheathing, you can get away with utilizing thick plywood boards instead. On the other hand, the inverse is not true. Since OSB easily cracks and gives way under weight, it cannot be used for structural sheathing activities.

Should You Use OSB or Plywood for Sheathing?

Plywood is superior than OSB in every way except thickness and should be used wherever possible for sheathing if money is no object. And the thickness can be adjusted to your liking (though you pay more for it). In most cases, hybrid solutions are chosen by home builders.

God of the Egg and Phoenix, King @king colorblind
Contrary Opinion: 3/8 x 4/8 x 8 Edition Plywood Sheathing https://t.co/CtwBblLIAQ
1:33 PM · Mar 17, 2019 27 \s1
Strong support beams and floors get the more expensive plywood planks. Beams and a busy floor are examples. Plywood sheathing is used as an underlayment in the latter.

Anywhere the primary function of the sheathing is thermal regulation, OSB is the way to go. OSB is not a good option for sheathing since it cannot absorb much shock.

As with plywood in general, the reputation of plywood sheathing can be tainted by common misconceptions. Plywood sheathing is often incorrectly assumed to be the same as cabinet-grade plywood because of common misconceptions about the two. That’s why they consider plywood subpar in terms of durability. Plywood, with the correct glue or adhesive, may be an excellent insulating material.

With an eye on savings, this video compares OSB with plywood.
When it comes to framing, what are the advantages and disadvantages of plywood and OSB?
Examining the Key Distinctions Between OSB and Plywood

Where Do You Get Sheathing Plywood?

Sheathing plywood can be purchased from any hardware or building supply store. When you go to a hardware store, you can ask for “structural plywood” or “sheathing ply,” and the employees will help you find the correct plywood sheets. Don’t use laminated or veneered boards, and stay away from finished plywood. You’ll need unfinished wood planks.

Final Thoughts

Plywood sheathing is robust plywood that is used to protect walls, floors, beams, and frames from the weather and high temperatures. To prevent water damage, it must be coated or covered.

You can use OSB for the ceiling and the roof, and sheathing ply for the floor and the beams if you’re on a low budget.

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