osb exposured to moisture

[dbags]

I am working on a residential house in which the 3/4" t&g osb subfloor was exposed to excessive moisture due to delays in roof construction (approx. 2 months worth). The subfloor is supported by 2x10 floor joists @ 16"oc. Overall, based on a limited visual inspection, some minor delamination is apparent with some isolated soft spots. The building inspector would like a recommendation from an engineer to determine the structural adequacy of the subfloor. From my point of view, structurally it appears adequate if the isolated soft spots are cutout and replaced with new osb, but I was considering recommending a 3/8" plywood overlay for the entire floor because of possible unseen damage due to the moisture exposure. Any recommendations?

 

[boo1]

Your approach sould appropreate. Thickness swell and its differentiation in adjacent OSB elements is worse at cut edges. Damage due to differential swelling also can be offset by the overlayment (I would use 1/2 inch) and sanding. Inshure NOFMA approved fasteners must be used and placed not more than 8" on center (I like screws and glue).

Additionally consider what is the finish flooring, wood and tile will need a differnent treatment and moisture checks. If mold is present recommend treatment before covering it.

 

[boo1]

Should have typed:
Your approach sounds appropriate.