If your eave is one straight length then pick an end and work to the other.
How to roof overlapping gables.
Start at the bottom side of the gable and overlap the sections of drip edge a few inches as you work your way up the roof see figure a.
Start by applying the drip edge to the eaves of your roof.
As you near the edges of the roof or any points where the roof has gables you may need to cut the sheets to custom fit the space.
If you align the shingle.
Put one shingle across the valley from the left the next row overlapping from the right for instance.
Then nail shingles on the new roof and exposed areas of the old roof.
Tips on how to install shingles on a straight gable roof.
Start by overlapping a starter from both sides of the valley at the bottom.
Installing asphalt shingles on a basic gable roof is one of the most straight forward of all roofing projects.
Finish your gable roof addition tie in by installing siding to match the existing house and fascia and trim boards at eaves and edges.
The majority of the metal sheets will go onto the roof whole and intact.
Fold new shingles over the new valley onto the old roof overlapping by at least a foot.
Measure and cut the metal sheet panels as necessary before installing them on the roof.
Weave and cut the valley on the highest side of the roof.
Use cap shingles or 12 inch shingle pieces to overlap the peaks.
Staple roofing paper on both gables with a construction stapler and install shingles.
Install the drip edge on the gable ends of the roof after you finish installing your underlayment.
Use a tin snips to cut the drip edge to size.
Then your first shingle goes on the side you are going to cut.