Roofing is Hard
Work by others: (Shingles bridge the gap between framing and trim)(floppy tails)…
The roofing contractor starts late, often on sub-par DESIGN, ARCHITECTURE, & FRAMING work, that happens after they price their work, possibly “by the square”, and its like standing in line to get whooped. Many building contractors reinforce this fault by prioritizing price and failing to consider quality, their clients referred to the roofing contractor, who can point finger at the roofing products, and even at the builder for being cheap. If a roof fails to last as long as it should, the framing and trim sequencing are often the culpritYou see, over the years layers of trim are added, and the roof decking falls way short. There is no way to fix this “NEW ROOF” other than ripping it off and re-decking the entire perimeter so that it overhangs the rafter edges and tails generously.
The most common installation in NC is the “half-tab offset” even for nicer “architectural shingles”, because it is the easiest and fastest method for installation. Often the installation of half-tab-offset and the “short decking epidemic” means that half of the roofing material within 6″ of the gable-end is nothing more than half-tabs with one nail in them each, and that nails is over 3″ from the edge of the shingle. With “short-decking” there is always an increased likelihood of leaks around the perimeter of the roof allowing for wind-driven rain to get under the shingle, long before the shingles themselves begin to fail. Flopping and flapping related to short-decking has been known to reduce the lifespan of shingles too. Short-decking also causes the gable end shingles to be inclined on the edge and depressed 3″ in from the edge, essentially causing the water to run down a slight valley where there is no decking or tar-paper beneath it.