I followed the instructions to a "T" when I did this in 1996.....But in talking to a roofer, he asked if I "face-nailed" the roll roof. I had to ask him what he meant, and he explained that was when bare nail heads were left exposed.
Well, yes, I did, although I covered each nail with that black roofing tar stuff.
Anyway, as mentioned I followed the instructions on the roll roofing and they showed face-nailing, but didn't mention the tar, that was my own idea.
The roofer laughed and said, "yeah, they do say to face-nail don't they."
He then said if I hadn't face-nailed, I might have gotten another five to seven years. Since he wants $700 to three-tab the roof, I thought I'd go back to the $40 roll roofing job and do it myself.
But, If I don't face-nail, how DO I do this. I looked in the roofing books at the local library, but they don't seem to cover roll roofing.