I have a shake roof (looks like the original from 1952!) with skip sheathing. Then an asphalt shingle re-roof over that (that makes 2 roofs in 60 years, thanks previous owners!). I have repairs and upgrades to make now and potentially would like to put a whole new roof on eventually.
Can I just strip shingles and shake, then put new decking ON-TOP of the skip decking (considering it is in good shape)? Or should I also rip out all the decking wood down to the rafters?
If I do put ply/osb over the skip deck, I'm guessing I should use longer nails and still try and fasten to the rafters? What is the advice there?