OSB Vs Plywood: What's the Difference?

What is OSB Board?

OSB (Oriented Strand Board) is a type of engineered wood made from compressed layers of wood chips and strands that are bonded together with wax and resin. These strands are arranged in specific orientations to provide stiffness, structural integrity and load-bearing performance.

Originally introduced as a more affordable alternative to plywood, OSB sheets are widely used in flooring systems, roof decking, wall sheathing and other structural applications. Standard panels come in sizes up to 2.4m x 1.2m, with common thicknesses between 6mm and 18mm.

Advantages of OSB:

• Cost-effective – Made from wood strands instead of veneers, OSB is cheaper to produce than plywood, offering similar performance at a lower price.
• Strong and dependable – Cross-layered strands bonded with resin give OSB reliable strength and stability for load-bearing applications.
• Easy to work with – Cuts cleanly and holds fasteners well using standard tools, making it quick to work with on-site.
• Water resistant – Modern adhesives help OSB resist short-term exposure to damp conditions during construction.
• Sustainable – Uses fast-growing species like aspen and poplar, reducing pressure on hardwoods and minimising waste.

Disadvantages of OSB:

• Not waterproof – Prolonged exposure can cause swelling or warping.
• Less rigid across the width – OSB can flex more than plywood, so it may need additional support in wide-span applications.
• Rough finish – The finish isn’t ideal for exposed or decorative use without additional cladding or covering.
  
• Edge sensitivity Unprotected edges are more prone to chipping during handling or fitting, particularly on-site.

What is Plywood?

Plywood is an engineered wood product made by bonding thin layers of wood veneer in alternating grain directions, forming a cross-laminated panel. This design improves dimensional stability, reduces warping and makes it strong in both directions.

It’s widely used in wall sheathing, wall flooring, furniture and interior joinery. Available in various types such as marine plywood, fire-retardant, hardwood, and softwood panels, plywood offers flexibility across structural and design-led builds.

Advantages of Plywood:

• Strong and rigid – Excellent load-bearing capacity thanks to cross-laminated layers that minimise sagging. 

• Dimensionally stable – Built from cross-laminated layers that balance internal stresses, helping it resist warping and twisting over time, even when exposed to changing humidity or temperature. 

• Attractive finish – Smooth wood veneer surface makes it ideal for visible or decorative applications. 

• Moisture resistance – Performs well in humid areas when properly sealed, especially in interior journey. 

• Wide variety –  Available in structural sheets and decorative grades, offering flexibility across applications.

Disadvantages of Plywood: 

• Higher cost – Plywood sheets are generally more expensive than OSB, due to the use of quality veneers.

• Heavier – Greater density means more weight per sheet, which can slow handling and increase transport costs. 

• Can delaminate – Moisture can break down the glue between layers if not properly sealed. 

• May contain voids – Lower-grade plywood can have hidden gaps,  which may weaken structural integrity or affect appearance. 

OSB vs Plywood: How to Choose the Right Material

When deciding between plywood and OSB, the best choice often comes down to key concerns- be it cost, finish or performance in load-bearing or humid environments: 

• Subfloors – Choose OSB flooring for strength, stability and cost-efficiency. Plywood may squeak unless glued and screwed.
• Wall sheathing – Both materials work well, but OSB board wood is more affordable. Always select a moisture-resistant grade.
• Roof decking – OSB sheets are widely used, though plywood offers better stiffness for longer spans.
• Furniture – Plywood is ideal for cabinets and joinery, thanks to its smooth wood veneer and clean edges.
• Humid areas – In basements, bathrooms or other damp conditions, plywood offers better moisture resistance over time. 
• Structural use – For hidden areas where finish isn’t key, oriented strand board OSB delivers reliable strength and value.

In summary, OSB is a cost-effective choice for structural applications like flooring, roof decking and wall sheathing, where strength and scale matter more than appearance. Plywood is better suited to interior joinery, furniture and projects that require a smooth finish or greater moisture resistance. The right option depends on your project’s needs and priorities.