[quote=“Chill77”]Thanks for the input.
Apart from two small areas still with cedar shakes, the majority of the home does in fact have asphalt shingles on already.
I don’t believe there are any smaller boards used on top of the planks…and the planks are pretty tight (probably less then 1’’ apart).
Since the asphalt is already on…does that mean it’s probably safe for me to go the same route while re-roofing? Or were the previous owners just lazy?
I did not mean to imply that the smaller boards would be “On Top” of the existing planks. The thinner boards would have possibly been used to “Fill In” the gaps between the old planks.
It sounds like, from your description, that the gaps are small enough to be able to remove the old roof and apply new composition shingles directly on top of the existing decking, without having to overlay the old decking plank boards with new plywood sheathing.
You might want to see if a local building inspector could come out prior to beginning the contract and verify if he feels that new sheathing overlay is required.
I prefer to tear off the old shingles. If you are thinking of Re-Roofing over the top of the existing ones, that is a very poor choice and will come back to bite you in the azz in a short time. Reroofs do not last as long, typically, as a proper new installation does, due to heat sumps trapped in between the multiple layers of shingles. This trapped heat and moisture decays the new surface shingles prematurely and also is not typically covered under the fine print of the shingle manufacturers warranty exclusions.