Capital Hardwood Flooring Recommendations

• Appropriate subfloor panels are referred to as oriented standard board (OSB). According to Capital Hardwood Flooring, the recommended minimum thickness of OSB is 3/4 inches, over joists spaces 19 inches or less apart. You also must pay close attention to the edges of your OSB. They must be dry and adequately glued or screwed to the joist to control noise in your new floor.
  
  

National Wood Flooring Association Recommendations

• The subfloor must meet minimum thickness requirements for a successful installation. According to the National Wood Flooring Association (NWFA), the subfloor should be 3/4-inch plywood or OSB for joists spaced up to 19.2 inches on center, and 7/8-inch plywood or OSB for spacing up to 24 inches on center. Its minimum requirement is 5/8-inch plywood for joists spaced at no more than 16 inches on center.
  
  

Builders Use

• Modern builders use both regular plywood and OSB for subfloors. They are both acceptable by hardwood flooring manufacturers and have been tested to be equal.
  Because of the testing and comparison, 3/4-inch plywood or OSB are acceptable for hardwood flooring subfloor as long as they are in good condition.
  
  

Remodeling

• If hardwood floors are installed or replaced during a remodeling, the subfloor must be inspected to ensure strength and thickness. If any areas are weak due to water or construction damage, these issues must be dealt with. Adding a layer of 1/2-inch plywood may be all you need to fix the problem.
  
  

Subfloor Too Thin

• If your subfloor is thinner than recommended, add a layer of 1/2-inch plywood across the existing subfloor to achieve the best results.