To attach regular or film faced plywood to eaves, we recommend pre-drilling countersink pilot holes. This keeps the number of splinters to an absolute minimum. Splinters can cause injuries and may damage the roof seal in the long run. Of course, that is not what you want. The countersink pilot holes make sure that the screw locks into the sheet surface perfectly. And they look very neat, too! Safety and efficiency make for good progress.
THE SOLID JOHN POLYMER
Bonding building materials together in damp conditions is par for the course