What should I do when nail in shingle hits sheathing's crack?

[DJW]

I am applying three tab Owens corning as to their nailing instructions with a hammer by placing the nail below the seal strip and above the split that forms the tabs. What should I do if my nail hits nothing? It is old plank sheathing 1940s vintage and when by chance the nail area is over the crack between boards I have found that one to three (or worst case all four) nails just go in fast and hit nothing. I have then at least been putting two more nails above the seal strip. I can figure no other option. I assume I should not pull the bad nails because of the hole created by them. I am concerned down the road that they may pop up a bit and effect the shingle over them. But what else could be done. When a nail goes in without hitting anything I try to adjust the next one over sometime with success and some times with the same no hit results. I start to use profanity when the next two or more do the same.

[Mike Hammer]

You HAVE to go above or below the crack. How wide ARE those cracks? Better to go high than too low. IF you have plenty of time, pull out the nail and remove the shingle. Put some cement over the nail hole and then replace the shingle. Others put the nail back in after cementing it. Still others just leave it alone. I wouldn't worry about the nail working its way back out. You shouldn't have any problems until the tabs become old and buckle.

[Alan]

With lumber prices as low as they are, you made a mistake in not resheathing the whole roof with OSB. I have plank sheathing, and layered OSB right over it, which is acceptable by code and provides a real firm roof deck. Plank sheathing is OK for wood shingles, but not so good for roll roofing and asphalt shingles. Before I reroofed, the leaks I had in my garage were between the planks where roll roofing had sagged and cracked. Generally though, the nails driven go all the way through the sheathing, so they really hold by mechanical leverage, not so much by friction. Definetly nail through the nail strip because the asphalt glue from the next shingle adheres to this. It's OK to put a nail above the nail strip if you want, but when you lay down the next row of shingles, you'll be doing that anyway. Each shingle then has two rows of nails, and the asphalt glue does a lot to keep the wind from blowing the shingles off. If it makes you feel any better, smear in some asphalt roof patch to hold the shingles together even more. Indeed, the warranty of the shingle in terms of its wind resistance is based as much or more on the thin line of asphalt glue than on the nail. It takes a few days of warm sun for the asphalt to stick firm for the long run though. Good luck.