For homeowners

Types of subfloor: which panel or board fits your floor?

Choose Plywood for glued tongue-and-groove joints, even where some wetting is expected; Oriented strand board (OSB) for sheathing or single-layer subflooring (it is usually marketed to a product standard for these uses); Particleboard for flooring systems, manufactured houses and use as underlayment (it can be used in each).

The right choice depends on how much wetting the floor may see, whether fasteners go near panel edges, and what underlayment the finish flooring needs.

How we know: By InstaBids editorial team with AI research agents. · Sources read: 17 October 2026 · Updated 27 October 2026

USDA Forest Service Wood Handbook (2021): "Floor sheathing, or subflooring, is used over the floor framing to provide a working platform and a base for the finish flooring."
Type	Best for	Main advantages	Main drawbacks
Plywood	glued tongue-and-groove joints, even where some wetting is expected	undergoes minimal irreversible thickness swelling if wetted; excellent dimensional stability along its length and across its width; its alternating grain resists splitting, so fasteners can be placed very near the edges of a panel	internal knotholes and voids may pose a problem in some uses (a solid core can be ordered); plywood outside the rated underlayment grades, such as luan, may lack exterior glue and may be susceptible to deterioration from moisture (HUD, 1999)
Oriented strand board (OSB)	sheathing or single-layer subflooring (it is usually marketed to a product standard for these uses)	greater bending strength and stiffness in the direction its strands are aligned; as makers learned to control strand size and orientation, its performance became similar to that of structural plywood	in a water-soak study of OSB flooring panels (USDA Forest Service record, 2005), thickness swelling at the edge exceeded swelling 1 inch in from the edge
Board (lumber) subfloor	no official source names one	boards acted as a diaphragm stiffening the floor structure and transferring lateral wind loads through the floor (HUD, 1999)	plywood and OSB panels are quicker to install and give improved structural resistance to wind and earthquake loadings, compared with boards; as solid wood, its strength and stiffness differ along versus across the grain much more than a plywood panel's do; where boards also served as the finished floor, shrinkage opened cracks between boards unless they were tongue-and-grooved (HUD, 1999); industry association guidance reported by HUD calls for a minimum of 11/32-inch underlayment over lumber subflooring to provide a uniform surface (HUD, 1999)
Particleboard	flooring systems, manufactured houses and use as underlayment (it can be used in each)	no official source names one	usually made with a UF resin; PF and MF resins are sometimes used where more moisture resistance is needed; early particleboard did not perform well in high moisture situations (HUD, 1999)

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Priority	Choose
glued tongue-and-groove joints where some wetting is expected	Plywood
fasteners placed very near panel edges	Plywood

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Sources for the facts on this page

USDA Forest Service, Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), chapter 11: Wood-Based Composite Materials, government, read 17 October 2026.
U.S. Department of Housing and Urban Development (HUD), The Rehab Guide, Volume 5: Partitions, Ceilings, Floors and Stairs (1999), government, read 22 October 2026.
USDA Forest Service, Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021), chapter 17: Use of Wood in Buildings and Bridges, government, read 22 October 2026.
USDA Forest Service research record (Treesearch 23123): comparison study of thickness swell of commercial oriented strandboard flooring products (2005), government, read 22 October 2026.