Fastener depth matters as much as location. Nails driven too deeply, left high or installed at an angle can impair holding or interfere with the next shingle
GAF technical bulletin: Improperly driven nails.
What this means for your roof
Fastener depth matters as much as location. Nails driven too deeply, left high or installed at an angle can impair holding or interfere with the next shingle. GAF describes correcting the affected installation rather than accepting a poor fastening pattern.
A useful question for your contractor
Ask how nail-gun pressure and fastener seating are checked during the job.
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin revision: February 1, 2021. This is the date of the manufacturer source, not a claim that this website guide existed on that date.
Read GAF: Improperly driven nails
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.