Which is Better: 1/2 or 5/8 Roof Sheathing?

If you’re in the market for new roofing, you may be wondering which type of sheathing to choose.

Two of the most common options are 1/2″ and 5/8″ roof sheathing, and each has its pros and cons.

While 1/2″ sheathing is lighter and less expensive, 5/8″ sheathing is thicker and more durable, making it a better choice for greater loads.

In this blog post, we’ll dive into the differences between these two types of sheathing to help you make an educated decision that serves your project requirements and budget.

So whether you’re a homeowner or contractor, keep reading to learn more about which is better: 1/2 or 5/8 roof sheathing.

Comparison Factors Between ½ and ⅝ Roof Sheathing

When it comes to selecting the right roof sheathing for your project, there are several factors to consider, including thickness, price, installation cost, rafter space, wood type, weight, sound insulation, and thermal insulation. Understanding the pros and cons of each factor can help you make an informed decision that meets your needs and budget.

Thickness

The thickness of roof sheathing is an important consideration when it comes to selecting the right material for your roofing project.

1/2″ roof sheathing is thinner than 5/8″ roof sheathing, which means it is lighter and more flexible.

This can make it easier to work with and install, especially in tight spaces.

However, the thinner material may be weaker than the thicker option, which may concern those living in areas with high winds or heavy snow loads.

Ideal Weather

The ideal weather conditions for using 1/2″ and 5/8″ roof sheathing can vary depending on the specific needs of your project.

For 1/2″ roof sheathing, mild and dry weather conditions are generally preferred.

This is because the thinner material may be more susceptible to damage in harsh weather conditions, such as high winds or heavy rain.

On the other hand, 5/8″ roof sheathing is better suited for moderate to high wind areas, as it provides greater wind resistance due to its thickness and strength.

Price

The price of roof sheathing can vary depending on several factors, including the thickness of the material, the type of wood used, and the specific manufacturer or supplier.

In general, 1/2″ roof sheathing is less expensive than 5/8″ roof sheathing, with prices ranging from $12 to $20 per sheet, while 5/8″ roof sheathing can cost between $18 to $30 per sheet.

However, it’s important to keep in mind that the exact price may vary based on your location and other factors, so be sure to get quotes from multiple suppliers before making a decision.

Installation Cost

The installation cost of the roof sheathing can vary depending on the material’s thickness, the roof’s size, and the project’s complexity.

In general, the installation cost of 1/2″ roof sheathing is lower than that of 5/8″ roof sheathing, with rates ranging from $40 to $60 per hour, while the installation cost of 5/8″ roof sheathing may range from $45 to $75 per hour.

Remember that these rates may also vary based on your location and the specific contractor you choose to work with.

Rafter Space

The rafter space is the distance between the roof rafters, and it is an important consideration when selecting the right thickness of roof sheathing for your project.

In general, 1/2″ roof sheathing is best suited for a rafter spacing of 16 inches in the center, while 5/8″ roof sheathing is better suited for a rafter spacing of 24 inches in the center.

This is because the thicker material is stronger and more rigid, allowing it to span greater distances without sagging or bending.

Best Wood to Use

The best wood to use with 1/2″ and 5/8″ roof sheathing can also vary depending on the specific needs of your project.

For 1/2″ roof sheathing, OSB plywood is generally preferred over CDX plywood due to its cost-effectiveness and strength.

OSB plywood is made from compressed wood strands, which makes it less expensive than CDX plywood while still providing good strength and rigidity for the thinner material.

On the other hand, for 5/8″ roof sheathing, CDX plywood is the preferred option, as it is stronger and more rigid than OSB plywood, providing better support for the thicker material.

Weight

The weight of the roof sheathing can also be an important consideration, particularly if you are concerned about the overall weight of your roofing system.

In general, 1/2″ roof sheathing is lighter than 5/8″ roof sheathing, which means it can be easier to handle and install.

This can be particularly beneficial if you are working on a project with limited access or are concerned about your roof’s weight-bearing capacity.

Sound Insulation

The thickness of the roof sheathing can also impact the level of sound insulation provided by your roofing system.

In general, 5/8″ roof sheathing provides better sound insulation than 1/2″ roof sheathing due to its increased thickness and density.

If you are concerned about noise levels in your home, particularly if you live in an area with high levels of traffic or other external noise sources, opting for 5/8″ roof sheathing may be a good choice.

Thermal Insulation

In general, 5/8″ roof sheathing provides better thermal insulation than 1/2″ roof sheathing due to its expanded consistency and thickness.

This can help keep your home warmer in the winter and cooler in the summer, reducing energy costs and improving your overall comfort.

When Should You Go For ½ Roof Sheathing?

In the United States, building codes typically specify minimum requirements for roof sheathing based on factors such as the type of roof covering, the slope of the roof, and the expected load on the roof.

For example, the International Residential Code (IRC) requires a minimum of 1/2″ plywood or OSB (oriented strand board) sheathing for roofs with asphalt shingles or other similar roof coverings where the roof slope is 4:12 or greater.

So, if you’re using asphalt shingles or a similar roof covering, and your roof has a slope of 4:12 or greater, you should use 1/2″ roof sheathing to comply with the IRC.

This will ensure that your roof meets the minimum requirements for structural integrity and resistance to wind uplift.

One important factor is the size and spacing of the roof framing members, such as the rafters or trusses.

If the framing members are spaced farther apart, or if they are undersized for the expected load, then thicker roof sheathing may be necessary to provide adequate support and prevent sagging or buckling of the roof deck.

Another consideration is the location and climate of the building. If the building is located in an area with high wind or snow loads, then thicker roof sheathing may be necessary to resist these forces and prevent damage to the roof structure.

Similarly, if the building is located in an area with high humidity or frequent rain, then thicker roof sheathing may be necessary to prevent moisture damage and rot.

It’s also important to consider the type of fasteners and fastening pattern being used to secure the roof sheathing to the framing members.

In general, it’s recommended to use nails rather than screws and to use a fastening pattern that meets or exceeds the requirements of the local building code.

Using an insufficient number of fasteners, or failing to space and stagger them properly, can compromise the strength and stability of the roof deck.

In summary, while 1/2″ roof sheathing may be sufficient for certain types of roofing materials and roof slopes, many factors must be considered when determining the appropriate thickness for a particular construction project. 

When Should You Go For ⅝ Roof Sheathing?

The International Residential Code (IRC) requires a minimum of 5/8″ plywood or OSB (oriented strand board) sheathing for roofs with tile or slate roofing materials, regardless of the roof slope.

If you’re using tile or slate roofing materials, you should use 5/8″ roof sheathing to comply with the IRC.

This will ensure that your roof meets the minimum structural integrity requirements and wind uplift resistance requirements. The thicker sheathing is required for these types of roofing materials due to their weight and the need for additional structural support.

In addition to tile or slate roofing materials, there are other situations where 5/8″ roof sheathing may be necessary.

For example, if the spacing of the roof framing members, such as the rafters or trusses, is greater than 16 inches in the center, thicker sheathing may be necessary to provide adequate support and prevent sagging or buckling of the roof deck.

Another consideration is the location and climate of the building. If the building is located in an area with high wind or snow loads, then thicker roof sheathing may be necessary to resist these forces and prevent damage to the roof structure.

Similarly, if the building is located in an area with high humidity or frequent rain, then thicker roof sheathing may be necessary to prevent moisture damage and rot.

One important factor is the expected load on the roof, which can vary depending on the intended use of the building.

For example, if the building will house heavy equipment or machinery, or if the roof will need to support a rooftop garden or solar panels, then thicker roof sheathing may be necessary to provide adequate support and prevent damage to the roof structure.

Another consideration is the insulation’s type and thickness in the roof assembly. Thicker roof sheathing can provide additional space for insulation, which can improve the energy efficiency of the building and reduce heating and cooling costs.

Additionally, thicker sheathing can help to prevent thermal bridging, which occurs when heat is conducted through the framing members and can reduce the effectiveness of the insulation.

It’s also important to consider the acoustic performance of the roof assembly, especially in buildings where noise from external sources may be a concern.

Thicker roof sheathing can help to reduce sound transmission through the roof, which can improve the comfort and productivity of the occupants.

Finally, it’s worth noting that while 5/8″ roof sheathing may be required for certain types of roof coverings or framing member spacing, using thicker sheathing can provide additional benefits in terms of durability and resistance to damage from moisture, pests, and other environmental factors.

Thicker sheathing can also provide a stiffer, more stable roof deck, which can improve the overall performance of the roof system.

Additional Maintenance Tips For Your Roof Sheathing

By following these tips, you can help ensure the long-term health and durability of your roof sheathing and prevent costly repairs down the line.

• Regularly inspect your roof sheathing for signs of damage or wear, such as cracks, warping, or rot. This will allow you to catch and repair any issues early on before they become more serious and costly to fix.

• Keep your roof clean and clear of debris, such as leaves, branches, and other debris that can accumulate and trap moisture against your roof sheathing. This can lead to rot and other damage over time.

• Ensure proper ventilation in your attic or roof space. Proper ventilation helps regulate temperature and moisture levels, which can prevent moisture buildup and help prevent mold and rot from forming on your roof sheathing. Consider adding additional vents if your roof space is poorly ventilated.

• Check for proper insulation in your attic or roof space. Proper insulation helps regulate temperature and prevent moisture buildup, which can help prevent damage to your roof sheathing.

• Seal any gaps or cracks in your roof sheathing to prevent moisture from seeping in. You can use roofing cement or other sealants to fill any gaps or cracks you find.

• Replace damaged or missing shingles or other roofing materials promptly to prevent water from seeping through to your roof sheathing. This will help prevent rot and other damage from forming.

• Trim back any overhanging tree branches that could potentially fall onto your roof and damage your sheathing or other roofing materials.

• Finally, be sure to always exercise caution when working on your roof. Wear proper safety gear, such as a hard hat and non-slip shoes, and use a sturdy ladder that is properly secured to prevent falls.

Bottom Line

While 5/8 sheathing may offer greater strength and stability, it also comes with a higher price tag and may not be necessary for all regions or for all types of roofs.

At the end of the day, it’s essential to work with a trusted contractor or builder who can help you assess your specific needs and recommend the best course of action for your unique situation.

By doing so, you can ensure that your roof sheathing is strong, durable, and able to withstand the rigors of your local climate and weather conditions.

Whether you opt for 1/2 or 5/8 roof sheathing, it’s important to stay on top of regular maintenance and upkeep to prevent issues such as rot, mold, and water damage.

By inspecting your roof regularly, keeping it clean and clear of debris, and addressing any issues as they arise, you can help ensure the longevity and performance of your roof.

FAQ

What is roof sheathing?

Roof sheathing is a layer of plywood or oriented strand board (OSB) that is installed on top of the roof framing to provide a flat, stable base for the roof covering.

What is the difference between 1/2 and 5/8 roof sheathing?

The main difference between 1/2 and 5/8 roof sheathing is thickness. The 5/8-inch sheathing is thicker and heavier than 1/2-inch sheathing and is often used for roofs with heavier loads or greater spans. However, 1/2-inch sheathing can be suitable for many roofs, depending on local building codes and climate conditions.

Can I use 1/2-inch sheathing for my roof?

The answer depends on your local building codes and the design of your roof. In many cases, 1/2-inch sheathing is suitable for residential roofs with normal load requirements. However, for roofs with heavier loads or greater spans, 5/8-inch sheathing may be necessary.