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How Thick Should Plywood Sheathing Be? (Explained)

People use different materials to attach to the roof. One of the lightest but strong materials are plywood. P

lywood is a mixture of different organic elements. Plywood sheathing is the layer of plywood that is attached to the rooftop. This is used to construct a sub-floor under the main rooftop.

Plywood sheathing thickness

Plywood sheathing thickness is written under the building code requirement, where a typical plywood panel should be 0.95 cm or 3/8 inches thick. This is the usual thickness that is vital. It is suggested to provide a little more thickness to the sheathing which is 1.2 cm or 15/32 inches for plywood.

But not all are the same. Let’s find out more about them.

Exterior plywood sheathing:

Plywood is lightweight also it is strong enough to hold strong wind or different weather. When you are using plywood sheathing for the exterior, you are ensuring that the building will be cool when the weather outside is hot.

And when the weather will be cool the relative temperature of the room will be hot. So, there are lots of good things on going about exterior plywood sheathing.

Exterior plywood sheathing is so strong that, it can stay strong in hurricane-prone regions as well. So, for hurricane-prone regions, people should install that type of sheathing.

The minimum appropriate thickness for plywood sheathing panels is 7/16 inches. Along with that, you should ensure the walls should have lateral stability at each story of the building. You can use a braced wall or shear wall from story to story.

For better aerodynamic shape and exterior, you can use plywood sheathing. The surface of the plywood is quite smooth. It is easy to pass the air easily.

So, building with plywood sheathing is strong against any powerful wind, such as hurricanes and other natural calamities. If you cannot do it yourselves, then you can have professionals for a relatively better price as well.

Interior plywood sheathing:

Interior plywood sheathing is quite common, as it is durable but not costlier than any other material. It is a great alternative to drywall. You can change the wall easily but if you put drywall, you have to break it to change it.

Interior plywood sheathing wall is widely used in the parking area. Drywall is not good with moisture or if you push anything against the plywood, then there is a problem as well.

It is even easier to insulate with insulating materials such as fiberglass insulators and then cover it up with a thick plywood sheathing.

Moreover, plywood sheathing is a good insulator of heat and cold temperature. As plywood is highly flexible to use, you can easily put screws, hooks, or anything as per your liking.

For the interior, you may need to have a half-inch (1/2 inch) plywood generally for a standard wall. But as per the residential code, you only need to have 3/8 inches wall sheathing when the studs are about 16 inches apart.

This basic formula is recommended when you are sheathing the inside of your house using plywood. Plywood is highly reliable, and you can have varieties of plywood to choose from.

What is code for plywood wall sheathing?

There are different regional and international codes or standards that need to be maintained to build a house. When you are building a house out of a plywood wall using sheathing, here is some rules and regulations as well.

The IRC or International Residential Code specifies that 3/8 inches plywood for sheathing walls is required, along with your need to have 16 inches of space in between studs.

Here another prerequisite is that the siding should be nailed to the studs through the plywood sheathing. Or you need to have a minimum of ½ inches thick plywood when the nails can penetrate only the plywood sheathing leaving the studs behind.

Basically, the margin of safety here is ½ inch thickness of the plywood. There you can use different sheathing materials as well, such as OSB, which is also widely used. For OSB, according to IRC, a 7/16 inches thickness is perfect.

What is the thickest plywood sheathing?

Plywood sheathing can come in different thicknesses. You can usually get ¾ inches thick plywood in the store, but the manufacturing facilities produce 1 inch to 1 and ¼ inches thick plywood as well which is the thickest.

Here you can make your own or customize your plywood as well. Plywood is used widely. Because the flexibility and the cost associated with using plywood are low.

To build an apartment, you need to stick to a particular code, here you have to maintain ¾ inches thick sheathing. But, if you want to increase the thickness of your plywood sheathing, then you can increase it as much as you want.

1 inch to 1 and ¼ inches is enough and recommended for proper plywood sheathing. If you increase more thickness of the sheathing, then you are adding more weight to the building thus, it will contain more temperature and cause your house to be a natural oven.

Three factors that determine plywood sheathing thickness

There are many things that determine the thickness. Let’s get to know them.


You cannot build a plywood sheathing or wooden house in between concrete apartments.

The surroundings of the building are one of the most important things. Plywood sheathing is more nature friendly than setting a building using cement and other material that remains as it is in a place for a longer time.

Though if you don’t want to change the building after a certain time, you may want to build something strong. Also, plywood sheathing should be used for framing, beams, or just flooring. It will reduce the overall weight of the building.

Weather of the Area:

If the place you are living is highly prone to hurricanes, tornados, etc. you should use plywood sheathing for your house. Nowadays, due to global warming, the amount of hurricanes or any natural calamities has increased.

During the past fifty years, according to WMO or World Meteorological Organization, the amount o natural calamities and their damaging capabilities have increased. The losses are projected to be 202 million dollars.

So, if you inject more money into your house, but it is in the area where hurricane yearly visits, then you are dumping all your money.

Building your house using plywood sheathing will increase the durability against any sort of natural calamities and it won’t cost you more.

Cost Associated with Building Plywood Sheathing:

Building a house using plywood sheathing is cost-effective. You can use OSB sheathing as well or drywall, both of them are usually costlier than plywood sheathing. Moreover, plywood sheathings are strong and durable enough to stay sturdy for a longer period.

Along with that, you can be creative with plywood. You can give any sort of shape to your plywood sheathing. Though plywood sheathing is not as energy efficient as ZIP sheathing.

The thermal and air resistance is well enough to cover all the seasons. The cost of plywood sheathing is less because it is more traditional than newer sheathing methods. And it is widely used.

What kind of plywood is used for sheathing?

Let’s get to know what plywood should you us for sheathing.

Softwood Plywood:

Softwood plywood is the best choice to make while you are using it for sheathing. It is not too thick not too thin. Two layers of smooth plywood sheet along with an internal core to it.

This plywood is both used for commercial spaces and for residential spaces. You can use softwood plywood for sheathing, and any other constructions such as sub-flooring, and framing.

Softwood plywood is made using different trees, such as spruce, pine, cedar, etc.

Structural Plywood:

Structural plywood is literally produced to give a proper structure to a building. That’s why this plywood is also known as sheathing plywood.

The strength of this plywood is quite high. Though these are not as smooth looking, or smooth to touch. You will get an unfinished vibe from the structural plywood.

Structural plywood is made using low-cost, C and D-grade woods, so the price level also is not as high as any other plywood. This is the best-performing plywood for sheathing.

Exterior Plywood:

The best thing about exterior plywood is that it is water-resistant. These are highly durable and can stand strong against high wind, snowfall, and any surprising weather conditions.

And this exterior plywood also stays safe for several years without any sort of damage. The exterior plywood is quite sturdy, and you can use them by gluing two or three pieces of plywood together.

You can use exterior plywood for framing and sometimes you can use them for sheathing.

Final Thoughts

Plywood sheathing is a more traditional approach. It is cheaper than any other sheathing technique. It is highly durable and natural calamities resistant. Also, there are IRC guidelines to ensure at least 0.95 cm or 3/8 inches thickness to 1 inches thickness. Plywood is light material for sheathing.