When starting a construction or renovation project, one of the important choices you’ll need to make is selecting the right wood paneling. Two common options are Oriented Strand Board (OSB) and plywood. While both are frequently used, they have unique characteristics that make them more suitable for different types of projects.
OSB is made from compressed wood strands, while plywood is made from thin layers of wood veneer, giving plywood better moisture resistance.
In this article, we will compare OSB and plywood, breaking down their properties, benefits, and drawbacks, so you can make an informed decision for your next project.
What is OSB?
Oriented Strand Board (OSB) is a type of engineered wood made from strands or flakes of wood that are compressed and bonded together with adhesives. The strands are arranged in layers, with each layer oriented at a right angle to the one below it, giving OSB its strength.
This material has gained popularity due to its affordability and versatility. It’s used in a variety of construction projects, including subflooring, sheathing, and roofing.
What is Plywood?
Plywood is another type of engineered wood, but it’s made by gluing together thin layers of wood veneer. These layers, or “plies,” are placed at right angles to each other to enhance strength and reduce the likelihood of warping.
Plywood has been around for much longer than OSB and is commonly used for flooring, walls, and roofing in both residential and commercial construction.
How OSB is Made
OSB is produced by combining wood strands with resins and waxes. The wood is cut into long, thin strands and then layered in a cross-oriented pattern. These layers are then pressed under high pressure and heat to form strong, dense panels. The resin used in OSB helps to bind the strands together and adds moisture resistance.
Because OSB is made from smaller wood pieces, it can be produced using fast-growing, often lower-quality trees, making it a more sustainable choice for some applications.
How Plywood is Made
Plywood is created by peeling thin layers from logs, which are then glued together. The grains of adjacent layers are oriented at right angles to one another, giving plywood its strength and resistance to warping.
The process of making plywood is more labor-intensive compared to OSB, as it requires high-quality wood veneer for the outer layers, especially for higher-grade plywoods used in visible applications.
OSB vs Plywood: Strength and Durability
When it comes to strength, both OSB and plywood have excellent structural properties. However, there are some differences:
- OSB is generally denser than plywood, which can make it stronger in certain situations, such as when used for shear walls.
- Plywood tends to perform better in terms of impact resistance and stiffness, which means it is less likely to bend or sag over time.
Both materials are strong enough for common construction tasks, but the specific application and environmental conditions will determine which is the better choice.
Moisture Resistance: OSB vs Plywood
Moisture resistance is a critical factor when choosing between OSB and plywood, especially for outdoor applications or in areas with high humidity.
- Plywood generally handles moisture better than OSB. It dries faster when wet and is less likely to swell or degrade after being exposed to water.
- OSB, on the other hand, tends to absorb and hold moisture more readily, which can lead to swelling and delamination, particularly around the edges.
For projects where moisture exposure is a concern, such as roofing or siding, plywood may be the safer bet. However, OSB manufacturers are continually improving their products to enhance moisture resistance.
Cost Comparison: OSB vs Plywood
One of the biggest advantages of OSB is its cost. On average, OSB is about 20% to 30% cheaper than plywood, making it a budget-friendly option for large-scale projects like sheathing and subflooring.
Plywood, while more expensive, offers better durability and moisture resistance, which can make it a better investment in the long term, particularly for projects in challenging environments.
Environmental Impact: Which is More Eco-Friendly?
Both OSB and plywood have environmental pros and cons:
- OSB is often considered more eco-friendly because it can be made from smaller, fast-growing trees and uses more of the wood, reducing waste.
- Plywood requires higher-quality logs, and its production process can generate more waste. However, some plywood manufacturers use sustainable harvesting practices to mitigate environmental impact.
In terms of sustainability, OSB has a slight edge, but both materials can be environmentally responsible when sourced from certified producers.
Applications of OSB
OSB is commonly used in the following applications:
- Wall sheathing
- Subflooring
- Roof decking
- Structural sheathing
- Packaging and crates
Its affordability makes it an excellent choice for large areas that need coverage without breaking the bank.
Applications of Plywood
Plywood is widely used in:
- Flooring underlayment
- Roofing and wall sheathing
- Cabinetry and furniture making
- Decorative finishes
- Boat building (marine-grade plywood)
Plywood is preferred in applications where strength, durability, and appearance are important.
Installation Process: OSB vs Plywood
The installation process for both materials is relatively similar, but there are a few key differences:
- OSB tends to be heavier and slightly more flexible, which can make it more challenging to handle during installation.
- Plywood is lighter and stiffer, making it easier to work with, particularly for overhead applications like roofing.
Both materials can be cut with standard woodworking tools, and their installation follows similar procedures in terms of fastening and joining.
Weight Differences Between OSB and Plywood
OSB tends to be heavier than plywood of the same thickness. This can be a consideration when working on projects where weight is a factor, such as when building a roof or carrying panels onto a job site.
Aesthetics: Does Appearance Matter?
For structural applications, aesthetics are rarely a concern. However, if the panel will be visible, plywood is the clear winner. Plywood’s smooth, wood-grain surface is more attractive and can be stained or painted to match the surrounding decor. OSB, with its rough, flake-like appearance, is not typically used for visible applications unless covered.
Which is Better for Roofing: OSB or Plywood?
Both OSB and plywood are commonly used for roof decking, but each has its advantages:
- Plywood tends to be preferred for roofing because of its superior moisture resistance and lighter weight.
- OSB, while cheaper, may require more maintenance or protective measures in areas with high rainfall or humidity.
If budget is a primary concern, OSB is a viable option, but for longevity and performance, plywood is often the better choice.
Conclusion
Choosing between OSB and plywood ultimately depends on your specific project needs. If cost is your primary concern and you’re working on a large-scale project like wall sheathing, OSB is a solid choice. However, for areas prone to moisture or where aesthetics are important, plywood is often the better option.
Both materials offer distinct advantages, so it’s essential to weigh factors like moisture resistance, strength, and budget before making your decision.
FAQs
Is OSB stronger than plywood?
OSB is denser, which can make it stronger in certain applications, but plywood generally offers better impact resistance and stiffness.
Can OSB be used for roofing?
Yes, OSB can be used for roofing, though plywood is often preferred due to its better moisture resistance.
Is plywood waterproof?
Plywood is not completely waterproof, but it handles moisture better than OSB, especially exterior-grade or marine plywood.
Which is more eco-friendly, OSB or plywood?
OSB is often considered more eco-friendly because it uses smaller, fast-growing trees and more of the wood from each log.
What is the main difference between OSB and plywood?
The main difference is how they are made: OSB uses wood strands, while plywood is made from layers of veneer. This gives them different strengths and weaknesses, particularly regarding moisture resistance and appearance.