The roof next door.
How can this happen?
It is easy to explain, really. The actual shingles are the same, but they are applied differently. Most shingles
are nailed higher, where the shingle is only one layer thick, and with less attention to how the nail is laid
down. Did it shoot through the shingle? Is it all the way down flush with the shingle? We also use more
nails per shingle than the average roofer. Spending the extra money on nails is well worth it in the long run.
Another difference in these two roofs is the attention payed to the valleys, or the areas between roof surfaces. We
always use metal in the valleys, and we put enough overlapping of the shingles in the valleys to reach as far back into the
area as possible.