Shingle Roof Installation
Two crews, one pallet of shingles, two very different roofs. Almost everything that separates them happens between the tear-off and the final sweep, under material nobody will ever see again. Here is that sequence, in the order it happens.
The deck sets the ceiling on everything
With the old roof stripped, the sheathing gets inspected board by board: soft spots, delaminated plywood, water-stained sections around old leaks, gaps at the seams. Nothing fastens properly to rotten wood and no underlayment bridges a bad deck. This is also the only moment in twenty years that anyone sees your roof structure, which is the main argument against laying new shingles over an old roof — that shortcut skips this step entirely.
Drip edge, underlayment, starter
Drip edge goes on at eaves and rakes so water lands in the gutter instead of behind it. Underlayment covers the deck as the secondary barrier for the day wind-driven rain gets past the surface. Where snowmelt refreezes at a cold eave and pushes water back beneath the courses, a self-adhered ice-and-water membrane at the eaves and in the valleys is what keeps that water off your ceiling. Then a starter course is bonded around the perimeter, giving the edge a continuous seal with no seams for wind to open.
The nailing zone
Every shingle carries a narrow band printed across it, and fasteners belong in that band and nowhere else. A nail driven above it misses the top of the shingle below and holds one layer instead of two. Driven too deep it cuts the mat; left proud it holds the next course off the roof. High nailing is behind a large share of the wind failures anyone in this trade gets called out to.
Six nails, not four
Four nails per shingle satisfies a standard installation. The manufacturer's highest wind warranty — usually 130 mph — generally requires six, plus that bonded starter. The published wind classes under ASTM D7158 (Class D at 90 mph, G at 120, H at 150) all describe samples fastened exactly to instruction, so a shingle installed with four nails is rated for a storm it has not actually been prepared for. The extra two nails cost labor and no material at all. Ask which pattern your quote assumes; the National Roofing Contractors Association publishes guidance if you want a second opinion in writing.
Airflow before the shingles go down
The code baseline is one square foot of net free ventilating area per 150 square feet of vented attic. The 1:300 figure everyone quotes is an exception you earn, generally by placing 40 to 50 percent of the required area within three feet of the ridge and the balance at the eaves. Intake and exhaust have to match. Adding exhaust over blocked soffits leaves the roof pulling makeup air out of the house. The cheapest hour to fix any of this is while the deck is open.
Flashing and finishing
New step flashing at walls rather than reused metal; pipe boots replaced, not resealed; valleys built to the method the shingle manufacturer specifies. Then the permit inspection, and a debris sweep and magnet pass across the yard and driveway before the trucks leave. On most houses the whole tear-off and reroof runs from early morning to done in a single day.
