Plywood versus OSB in Commercial and Residential Framing

Plywood versus OSB

Plywood and OSB Cost on last lumber bid - 7-15-2008:

Qty:	Type	Cost per Sheet
1056	CDX plywood 15/32" Struct 1 Exposure 1 4x8 32/16" span rating	$13.90
600	OSB 15/32" Struct 1 Exposure 1 4x8 32/16" span rating	$13.10
600	CDX plywood 15/32" Struct 2 5-ply Exposure 1 4x8 32/16" span rating	$12.75
600	OSB 1/2" Struct 2 Exposure 1 4x8 32/16" span rating	$7.85

There's no price savings at all using Struct 1 OSB versus Struct 1 CDX plywood , but there's a big difference in the price for CDX 5 ply plywood versus OSB Struct 2.

SBE Builders will only use CDX plywood or OSB that has a APA rated sheathing stamp with a EXPOSURE 1 stamp. This APA stamp guarantees that waterproof resins and glues were used to bond the CDX plywood or OSB to the wood fibers. EXPOSURE 1 CDX plywood and OSB are made to withstand repeated rainfall with little or no damage during a normal time frame construction project. However, the creep - edge swelling of OSB does pose problems when OSB is used for subfloors that receive ceramic title as a finished floor. Acorrding to Georgia Pacific they have test results stating CDX plywood is stiffer than OSB. This may be true for 3/4" CDX plywood, but when we use 1-1/8" OSB Gold Bond subfloor on our custom homes we've seen excellent results and a very stiff floor, ideal for cermica tile and other heavy surfaces.

Georgia Pacific article on plywood versus OSB Versatility, Stiffness, Creep - edge swell. This page is in favor of CDX plywood.
Plywood and Oriented Strand Board (OSB) for Roofs
Stiffness.19/32" plywood is 220% stiffer than 7/16" OSB.
Nail withdrawal strength. 19/32" plywood holds roofing fasteners 46% to 76% better than 7/16" OSB.

Georgia Pacific article on plywood versus OSB Versatility, Stiffness, Creep - edge swell. This page is in favor of CDX plywood.
Plywood and Oriented Strand Board (OSB) for Floors

Article on plywood versus OSB at The Family Handyman. This page has a really good photo of OSB panel edge swelling. This page is in favor of CDX plywood.
OSB is equal to plywood in strength, is slightly cheaper, but is more vulnerable to water damage

Oriented Strand Board Vs. Plywood . This page is in favor of OSB.
WHAT'S THE DIFFERENCE?

Oriented Strand Board Performance at OSB Guide. This page is in favor of OSB.
OSB In Wood Frame Construction Technical Manual

An excellent article comparing Plywood to OSB is available from the University of Massachusetts website. Recently we’ve heard that walls in many Southeastern homes covered with the Exterior Finish and Insulation System (EIFS) were rotting. Rigid foam insulation was applied over osb and coated with a stucco-like covering. When the exterior foam boards were removed, wet, rotted, crumbling osb was exposed. Osb was slammed in the press. The problem really isn’t osb’s fault. All cases I’m familiar with were caused by improper installation of flashing or protective coverings. .
University of Massachusetts