Emotions get called into the debate over plywood vs. OSB for flooring. I admit to having my own, too. But emotions aside, which one is better?
Defining Plywood and OSB
First, let's get definitions out of the way. Most of us are familiar with the general nature of plywood. But homeowners who don't work with plywood a lot may not know that plywood's great structural strength can partially be attributed to its perpendicular layers of veneer. These veneers are laid back and forth and glued together until a cohesive "sandwich" is formed.
OSB stands for oriented-strand board. OSB looks like large flakes of wood compacted together into a sheet. In fact, that's just what it is: about 50 layers of these "flakes" arranged perpendicularly and sealed together with phenolic resins to make a single sheet.
Compared to plywood, OSB is a relatively new building product. A leading manufacturer of both plywood and OSB, Georgia-Pacific, has been making plywood since 1964, but OSB only since 1982.
How do plywood and OSB stack up in major categories? Let's take a look:
Across equally-spaced joists
, plywood can be up to 10% stiffer than OSB.
OSB can be up to $3 to $5 per panel. For an average-sized home, this can represent up to $700 in savings. At the time of this writing, it is difficult to make an apples-to-apples comparison. However, 7/16 in. x 4 ft x 8 ft. OSB Sheathing Board costs $7.47 at The Home Depot. We also found that 19/32" x 4' x 8' Fir Rated Plywood Sheathing costs $15.97.
OSB has waxes, which can compromise adhesion. Plywood's porous surface is excellent for adhesives.
4. Best Under Ceramic Tile
Plywood works better as a substrate
below tile because of its stiffness. Any type of flex will cause cracking in tile's grout and even in the tile itself.
If huge panels are of a concern, you'll find that OSB offers panels up to 8' by 24'.
OSB's untreated, cut edges do not hold up well against moisture. Some OSB manufacturers even make a point of warranting their OSB for as long as 90 days against edge-swell. But that kind of protection against edge-swell is inherent in plywood.
Panel-weight can be a big issue when you are remodeling by yourself. Even hoisting a 4' x 8' plywood panel can get tiring by the end of the day. But imagine carrying a panel that is 15% heavier: OSB.
Both OSB and plywood are covered up in flooring applications, so appearance of the subfloor does not matter. In a pinch--if the surface had to be exposed--you could say that plywood wins out, due to its true wood grain look vs. OSB's flaky appearance.
9. Green and Eco-Friendly
OSB is chipped out of smaller trees and thus more productively uses timber than plywood.
10. And The Experts Say...
Contractors tend to give higher marks to plywood than OSB in all three applications: flooring, sheathing, and roofing. Even Georgia-Pacific, manufacturer of both OSB and plywood, weighs in on the plywood side of the argument at least for flooring.