Before the crew arrives
A roofing contractor typically pulls the local building permit before work starts, orders material to match the measured roof area in squares (a square equals 100 square feet), and schedules delivery so bundles land in the driveway or get hoisted straight onto the roof. Expect tarps over landscaping, plywood over windows near the work area, and a plan for sweeping stray nails out of the yard at the end of each day.
Before any of that, the contractor should already know from a roof inspection how many layers of material are already up there, since the building code caps a roof at two layers total once new material goes on. That number decides whether the job ahead is a recover or a full tear-off.[1]
Tear-off and deck inspection
On a tear-off job, the crew strips every layer of old material down to the bare wood deck. Fixr's roofing cost data prices that stripping-and-disposal step at about $50 to $150 per square, with the high end reflecting heavier materials and a second or third layer to haul away.[2]
With the deck exposed, the crew walks the whole surface looking for soft, delaminated, or water-stained plywood. Fixr puts deck sheet replacement at roughly $2 to $8 per square foot, so finding a handful of bad sheets usually adds a modest line item rather than blowing up the budget.[2]
A full tear-off also gives the crew a rare chance to check the underside of the deck from the attic once the old covering is gone, spotting daylight gaps, rot, or old leak stains that a recover would leave covered up.
Underlayment, flashing, and drip edge
A water-resistant synthetic underlayment goes across the entire deck first. At eaves, valleys, and anywhere a slow leak would be hard to trace later, crews add a self-adhering ice-and-water barrier on top of that, which Fixr prices at around $50 per square.[2]
New metal flashing goes in wherever the roof meets something else: step flashing along sidewalls, counter-flashing at chimneys, and boots around vent pipes. A drip edge runs the full length of the eaves and rakes so runoff clears the fascia instead of running in behind it.
Field material and ridge
The field material goes down last, following the manufacturer's nailing pattern and starting-course instructions, which is also what keeps a wind or manufacturer warranty valid. Ridge cap covers the peak, often paired with a ridge vent that ties into the attic's ventilation.
Final walk and permit close-out
A finished job typically ends with a magnetic sweep of the yard, driveway, and any planting beds for dropped nails, plus a haul-away of the old material and packaging.
Where the job needed a permit, the local building department still has to sign off with a final inspection before the job is officially closed. Keep that paperwork with your warranty documents; a home sale or a future insurance claim may ask for it.