Roof Decking Materials: Plywood vs. OSB - Which is Right for Your Roof?

When it comes to roofing, one of the most critical components is the decking material. Roof decking provides the structural base for the roofing system, supporting the weight of shingles, tiles, or other roofing materials while also providing a flat surface for installation. Two common choices for roof decking are plywood and oriented strand board (OSB). In this article, we'll explore the differences between plywood and OSB to help you determine which material is best suited for your roofing project.

Plywood: Time-Tested Durability

Plywood has been a staple in construction for decades, prized for its strength, durability, and reliability. Made from thin layers of wood veneer glued together in alternating grain patterns, plywood boasts excellent structural integrity and resistance to warping or splitting. Here are some key features of plywood as a roofing decking material:

  1. Strength and Stability: Plywood's cross-grain construction provides superior strength and stability, making it ideal for supporting heavy roofing materials and withstanding structural loads.
  2. Moisture Resistance: Exterior-grade plywood is manufactured with waterproof adhesives and can withstand exposure to moisture without delaminating or deteriorating.
  3. Ease of Installation: Plywood's uniform composition and smooth surface make it easy to install, ensuring a flat and even base for roofing materials.
  4. Longevity: When properly installed and maintained, plywood roof decking can last for decades, providing lasting protection and stability.

OSB: Cost-Effective Performance

Oriented strand board, or OSB, has gained popularity as an alternative to plywood in recent years due to its affordability and availability. OSB is composed of compressed wood strands bonded together with adhesive under high pressure, resulting in a strong and uniform panel. Here's what you need to know about OSB as a roofing decking material:

  1. Affordability: OSB is typically more budget-friendly than plywood, making it an attractive option for cost-conscious homeowners and contractors.
  2. Structural Strength: While OSB may not have the same inherent strength as plywood, it still provides sufficient structural support for most roofing applications, especially when properly installed.
  3. Moisture Resistance: Although OSB is susceptible to moisture absorption and swelling compared to plywood, advancements in manufacturing have led to moisture-resistant OSB options suitable for roofing applications.
  4. Availability: OSB is widely available at most lumberyards and home improvement stores, making it a convenient choice for roofing projects.

Choosing the Right Material for Your Roof

When deciding between plywood and OSB for your roof decking, several factors should be considered, including:

  • Budget: If cost is a primary concern, OSB may be the more economical choice. However, consider the long-term value and durability of plywood.
  • Climate: In regions with high humidity or frequent precipitation, plywood's superior moisture resistance may be advantageous.
  • Roofing Material: Certain roofing materials may require specific decking substrates for optimal performance. Consult with your roofing contractor or manufacturer for recommendations.
  • Local Building Codes: Check local building codes and regulations to ensure compliance with requirements regarding roof decking materials.


In conclusion, both plywood and OSB are viable options for roof decking, each offering its own set of advantages and considerations. While plywood is renowned for its strength and longevity, OSB provides a cost-effective alternative without compromising performance. Ultimately, the choice between plywood and OSB will depend on your specific needs, budget, and preferences. Consult with a qualified roofing contractor or professional to determine the best decking material for your roofing project. With the right material and proper installation, you can ensure a sturdy and reliable roof that will protect your home for years to come.

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