Is OSB OK in the rain?
OSB is rated “Exposure 1” and that means that it will withstand normal delays in construction. Normal delays and the rain you indicated will not affect the structural properties of the panels. Certainly it would have been better to have covered the roof with a tarp or roofing felt before it rained.
Will OSB dry out?
OSB's other moisture challenge has to do with dimensional stability - in other words, OSB can irreversibly swell, especially at the edges, when it gets too wet. It is important to note that OSB is not extremely sensitive to small amounts of water, and it absorbs water slowly. However, it is also slow to dry out.
How long can roof sheathing be exposed?Can OSB be stored outside?
Exterior-rated materials (exterior plywood, OSB, etc.) can be safely stored outside, but they should be covered – remember that most exterior-grade materials are rated for intermittent moisture exposure, not constant direct wetting.
How long will OSB board last outside?
For exterior applications, if you are not painting the OSB directly after installing it, be aware of how long you have before the material begins to be affected by the elements. For example, Weyerhaeuser Edge Gold OSB panels are warranted for 200 days against edge swell caused by water absorption.
Will OSB stand up to weather?
Building products such as OSB sheathing and wood framing are not designed to be exposed to the weather unprotected for lengthy periods of time.
How long can OSB get wet?
It only took about 30 minutes to do an average subfloor. The water repellant prevented swelling of plywood and untreated OSB. Once your house is under roof and there's little chance of the lumber getting wet, you may want to do some first aid and preventative care.
