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Roofing Sheathing Thickness Ultimate Guide

Roofing Sheathing Thickness Here's What You Need To Know

The roof protects us from the different environmental changes. However, with all the rain, heat, and snow it deals with, the roof also gets damaged from it. Sheathing the roof strengthens the roof by providing additional support for the roof system.

In this article, you will know more about roofing sheathing, the types of roofing sheathing, and the ideal roofing sheathing thickness for your roof.

Knowing how to make your roof sturdier will give you and your family a safer place to stay. This will also prevent you from further damaging your roof, which would cost more than what roofing sheathing would cost you.

What Is Roof Sheathing? (Roofing Sheathing Thickness)

Roofing sheathing, or roof decking, is a strong layer of wood boards that are placed on the trusses and joists of the roof. Roof sheathing is usually composed of 4-by-8-foot sheets that are installed perpendicularly to the roof frame.

Sheathing, on the minimum, is 19/32-inch thick. Roofing sheathing is done by attaching shingles to the planks of wood.

Roof sheathing is made of either oriented strand board (OSB), and in some cases, plywood. Although both are made of wood, OSB is preferred because of its lightweight and cheaper material.

Although plywood is durable, it tends to be heavier and more expensive. This is the reason why most construction professionals prefer OBS.

The primary purpose of roof sheathing is to strengthen the roof. It offers a sturdy support system that supports the rest of the roof system.

Thus, it is overall a good choice for providing additional support and protection to your roof.

Benefits Of Roof Sheathing

Roof sheathing helps distribute the weight of the entire roof evenly. Due to the sheathing boards attached to the roof system, it makes sure that heavy rain and snow do not cause sagging or bowing.

Since most sheathing boards are weatherproofed, having roofing sheathing helps prolong the lifespan of the roof and is safe from water leaking.

Asphalt shingles are commonly weatherproofing treatments and adding sheathing to this gives them an additional layer of protection.

When a massive snowstorm or typhoon goes near your home, roof seething assures your roof of no sagging or bowing.

Roof sheathing also has a fire-retardant treatment that helps prevent attic fires.  Attic fires are prone to homes that are heat-insulated and exposed to extreme heat during the day. 

If a roof has also passed its time of prime, it will be prone to breakage and damage from environmental changes.

For homeowners who opt to seldomly check up on their roof, roof sheathing will be a sustainable solution to secure the roof system in your home.

Roofing Sheathing Thickness

Types Of Roof Sheathing

Roof sheathing is the surface protection that roofing materials attach to. There are three common types of roof sheathing: OBS, plywood, and wood board. These materials can be bought with the advice of a professional roofer depending on the budget and durability status of your roof.

Strand board (OSB)

This type of roof sheathing is the preferred option in the present. This is due to the fact that it is cheaper and relatively durable.

Over 50% of new home construction in the United States includes this type of roof sheathing. OSB is a synthetic material that is made from wood fragments.

All of the fragments are held together by a specialized adhesive. The integration of the wood sheathing to this type gives the result of sturdy and strong roofing support.


Aside from OSB, plywood is also made from sheets of intertwined wood. The multiple sheets create thick sheathing which helps reduce warping and shrinking over the long term.

Plywood is also a dense material. As it is dense, moisture has a difficult time entering the wood and causing damage and rotting to your home and to the roof. 

Compared to other wood-based sheathing materials such as OSB, this type also has the same features such as strength and durability.

Wood Board

This type of roof sheathing was installed in homes in the 20th century and earlier. Wood board is also a wood-based sheathing, like OBS and plywood.

They were used to support roofing shingles and wood shakes. In order to speed up the drying process, shakes and shingles were placed over this wood-based sheathing.

Certain gaps are left between each board to encourage airflow in the roof. After the original wood shingles and shakes failed, they were replaced with roofing shingles made of asphalt.

However, the downside of asphalt shingles is it requires homes to have durable and solid sheathing.

Roofing Sheathing Thickness

What Is The Ideal Roof Sheathing Thickness?

On average, the thickness range for sheathing is 3/8 to 3/4 inches. The choice of roof sheathing thicknesses varies depending on what store you shop at and what is advised by a roofer.

However, when it comes to choosing a sheathing thickness, it is preferred to choose one that is thicker. A thicker sheathing means would secure a stronger roof deck and fewer possibilities of sagging.


It is important that when your home or commercial building is in need of roof sheathing, you hire experienced roofing contractors. These professionals know the best type of sheathing for your roof or structure, as well as the more efficient and durable materials, clips, and fasteners that should be used.

You want to be assured that your roof will avoid structural failure due to weather-related sheathing loss.

While DIY is appropriate for some projects, it can be a catastrophe for others. Replacing your own roof is at the top of the list of home improvement jobs you should leave to the pros.

Roofing Sheathing Thickness