All manufacturers of siding products I contacted agree that osb and plywood are equals. Kevin Chung, Engineer with Western Wood Products Association in Seattle assures us, There have been no problems reported from the field. Nail-holding and racking resistance are the same. Chung has noticed some concern about the use of osb among builders, but is quick to add, There is no reason for any concern. Both products serve equally well as a nailbase.
Roof sheathing is a mixed bag.
Warranties on shingles are extended to both substrates, but manufactures feel more comfortable with plywood. Mark Graham, NRCA s associate director of technical services says, We hear a lot of complaints related to dimensional stability. And a disproportionate number are related to osb. So we are a little bit cautious. Grahm also acknowledges that APA, an organization he clearly respects, is standing firmly behind the osb product.