Do not install flooring directly over joist without subflooring.
All structural panels/underlayment must be installed sealed-side down, and provide ¾” perimeter spacing. Square-edged or non tongue and grooved panels used as a subfloor will require a minimum 1/8˝ (3 mm) expansion space between all plywood seams.
Panels must meet minimum CDX grade Exposure 1 and US Voluntary Product Standard PS1-95, PS2-04 or Canadian performance standard CAN/CSA 0325-0-92 for construction sheathing. Check underside of panel for codes. Minimum of 3/8˝panel thickness is recommended when used as an underlayment.
Note that joist spacing determines minimum subfloor thickness.
• Joist spacing 16” on center (oc)
Plywood: Minimum of (5/8˝) Oriented Strand Board (osb): Minimum (3/4˝, 23/32”) Advantech Minimum (3/4˝, 23/32”)
• Joist spacing 16” up to 19.2” (oc)
Plywood: Minimum of (3/4˝, 23/32”) Oriented Strand Board (osb): Minimum of (3/4˝, 23/32”)
• Joist spacing over 19.2”up to maximum 24” (oc)
Plywood: Minimum of (7/8”) Oriented Strand Board (osb): Minimum of (1”)
• Particleboard or Masonite: is not recommended, remove or cover with 3/8” plywood.
•Avoid pressure treated plywood for interior use as these can have elevated moisture content or latent with rot resistant chemicals.
You can find complete installation instructions on the product page by clicking on the specs tab and then clicking on - Installation Guide.pdf
Thank you for your question.
Answered on 1/6/2012 by customer care 2