Roofing Plywood Thickness: A Guide to Choosing the Right

As a homeowner who recently started a roofing project, I can attest to the important role that roofing plywood thickness plays in the roof’s overall strength and durability.

Throughout my research, conversations with experts, and personal experience, I have gained valuable insights that I believe will be useful to those considering roof upgrades.

One of the first factors to consider when choosing the right thickness of roofing plywood is the distance between the rafters supporting the roof.

It is very important to match the thickness of the plywood to the distance between the rafters to ensure optimal load-bearing capacity.

Experts recommend using ⅜ inch-thick plywood for rafters that are 16 inches centered, while ½ inch-thick plywood is suitable for rafters that are 24 inches centered.

This prevents the plywood from sagging and provides a stable surface for the roofing material.

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Understanding Roofing Plywood Thickness

Roofing Plywood Thicknes

When it comes to roofing plywood, the most common thicknesses available in the market are 5/8 inches, 3/4 inches, and 1/2 inch. Each thickness has its own set of advantages and is suitable for specific roofing scenarios.

5/8 Inches Roofing Plywood

5/8 inches roofing plywood

5/8 inches of roofing plywood is the most widely used thickness for roofing projects.

It boasts sufficient strength to support the weight of most roofing materials and can withstand moderate snow and wind loads.

This makes it an ideal choice for roofs in areas with mild to moderate weather conditions.

3/4 Inches Roofing Plywood

3/4 inches roofing plywood

If your roof is prone to heavy snow or wind loads, or you intend to use heavier roofing materials like metal roofing, opting for 3/4 inches roofing plywood is a wise decision.

This thicker plywood offers enhanced durability and can better withstand the additional stresses posed by harsh weather conditions and heavier roofing materials.

1/2 Inch Roofing Plywood

1/2 inches roofing plywood

1/2 inch is the thinnest plywood typically used for roofing. While it may not possess the same strength as its thicker counterparts, it can be a suitable choice for roofs in regions with low snow and wind loads.

For areas prone to severe weather conditions, 1/2 inch plywood may not provide adequate support.

The Impact of Plywood Grade on Roofing

In addition to thickness, the grade of plywood also plays a crucial role in determining its strength and suitability for roofing applications. For roofing projects, it is essential to use structural grades of plywood, such as CDX or OSB.

CDX Plywood

CDX plywood is one of the most commonly used structural grades for roofing. The ‘C’ stands for the face veneer grade, which may have visible knots and imperfections. The ‘D’ represents the back veneer grade, which can also have knots but is still structurally sound.

CDX plywood offers a good balance of strength and affordability, making it a popular choice for many roofing projects.

OSB Plywood

Oriented Strand Board (OSB) is another widely used structural grade plywood for roofing. It is composed of wood strands that are layered and compressed to form a sturdy panel.

OSB plywood is strong, durable, and less susceptible to water damage than traditional plywood. Its popularity has grown significantly in recent years due to its cost-effectiveness and overall performance.

Roof Rafter or Truss Spacing Considerations

The spacing between your roof rafters or trusses also affects the thickness of plywood required. If your rafters or trusses are spaced more than 16 inches apart, you will need to use thicker plywood to ensure sufficient support across the larger spans.

Consulting with Roofing Experts

While understanding the various factors that influence roofing plywood thickness is crucial, it is always best to seek advice from professionals. Consulting with a reputable roofing contractor or engineer is highly recommended.

They possess the expertise and experience to assess all the relevant factors, such as the roofing material, roof slope, climate conditions, and structural requirements of your specific project.

Their insights will help you make an informed decision and ensure that your roof remains sturdy and durable for years to come.


Choosing the right roofing plywood thickness is vital for the long-term structural integrity of your roof.

It depends on various factors such as the type of roofing material, local climate conditions, and the spacing of roof rafters or trusses.

Opting for the appropriate plywood thickness, along with the right grade, will provide your roof with the strength and durability it needs to withstand the challenges of the elements.

When in doubt, always seek guidance from roofing professionals to ensure the success of your roofing project.

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As an expert in the field of garage walls, I have extensive knowledge and experience in enhancing the aesthetic appeal and functionality of these spaces through color and decoration. I specialize in creating visually appealing and practical designs that transform garages into inviting and organized environments.

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