Can a roofer put Norbord 7/16 on my roof when I have real wood on it too?
Dona Bruce, Powell, TN
Thank you for the e-mail and question Dona. I suggest you check with your local building department to make sure there are no building code regulations regarding this. Ideally the boards would be removed but that certainly would add to the cost. Many roofers have installed OSB over roof boards if the boards are in good condition. If the boards are cupped or in bad condition you may want to consider replacing the ones with issues or sanding down any places where the edge of the boards are not even.
Any variations that exist currently in the roof (i.e. rafters that are out of alignment) will still be there even when overlaid with OSB. The flatter and smoother the surface, before installing the new OSB, the better the finished job will be. You must have a good solid nailing base for the panels and your new roofing material. As with any roof please make sure you have proper attic ventilation and the roofer spaces all the edges of the OSB 1/8″ to allow for expansion due to changes in moisture conditions.