Weyerhaeuser is occasionally asked if our OSB floor sheathing panels such as EdgeTM or Edge GoldTM are warranted for use in premanufactured garden sheds. And as a secondary question, do we have any coating recommendations to ‘seal’ the top surface against contaminants (from stored equipment gas/oil leakage since there are no finish surfaces on top of the OSB deck).
Weyerhaeuser OSB panels are warranted against delamination when properly installed in a home. As a result, this application is outside the scope of the Weyerhaeuser Warranty.
Functionally, the panels perform the same whether installed on residential floor joists or garden shed floor joists. Environmentally, however, the applications can be radically different.
Residential building codes generally require a minimum clear distance between the floor structure and the ground surface below. If that clear distance cannot be maintained, then preservative treated framing material must be used to prevent decay due to long term exposure in high moisture conditions near the soil.
Garden/utility sheds have few requirements regarding placement or support. They are often minimally supported with the floor framing a few inches above the ground surface. This type of environmental condition may lead to decay and compromised structural integrity long before the 25 to 50 year warranty period for the Weyerhaeuser panel expires.
As for what coating may be effective in preventing/limiting absorption of various utility shed chemicals, Weyerhaeuser has no experience with such and can offer no recommendations. Note that the top surface of the uncovered OSB panels could possibly develop ‘strand pops’ over time and has voids that could trap organic material which could promote decay.