I just started pulling up shingles to reroof a 1989 house only to discover the plywood sheathing was installed without gaps. As a result, there is a lot of 1/4 inch buckling, especially on the unsupported seams.
Can I run a circular saw on all the seams set to the depth of the plywood to add spacing? Will the buckles ever lay flat or do I need to replace all the panels with buckling? can I put 2x4 pieces underneath in the attic and screw through the sheathing to try to level it out?