Tear-off, not overlay
Laying new shingles over old is allowed in some cases and it is nearly always a mistake. It hides decking problems, adds weight, shortens the new shingles' life because they cannot lie flat, and complicates the next replacement. We tear off to the deck on every job so the decking can be inspected and any rotten sheets replaced.
On older Clarksville homes the deck is often plank boards with gaps, which may need overlaying with plywood to give the nails something to hold.
The layers that go on
Drip edge at the eaves, then ice-and-water membrane along the eaves and in every valley, then synthetic underlayment over the rest of the deck, then drip edge at the rakes over the underlayment. Starter strip along the eaves and rakes so the first course seals against wind. Then the shingles, then step and counter flashing at walls and chimneys, then ridge vent and caps.
Each of those layers is there to handle a specific failure. Skipping one saves an hour and costs the roof years.
Architectural shingles and wind ratings
Architectural, or dimensional, shingles are the standard here for good reason. They are thicker than three-tab, carry higher wind ratings and hide the unevenness of an older deck. Most carry a wind rating that covers what a Middle Tennessee storm front delivers, provided they are nailed in the right zone with the right number of nails, which is where a lot of installations fall short.
Impact-rated shingles are worth discussing on roofs that have been hit by hail more than once.
Ventilation is part of the roof
A replacement is the moment to fix attic ventilation. Continuous ridge vent paired with clear soffit intake moves air through the attic, drops the summer attic temperature and keeps winter condensation off the decking. Old box vents and gable vents are removed or sealed so the system draws properly.
Timeline and weather
A typical single-family roof is stripped, dried-in and shingled in one to two days. We never strip more than can be dried-in the same day. During spring storm season the schedule is built around the forecast and can shift by a day or two, and you hear about it before the crew is due.
What you receive at the end
The photo record from tear-off through completion, the shingle manufacturer's warranty registration, and a note on the ventilation and flashing details. Magnet sweep of the yard and driveway is the last task before we leave.