What Happens During a Roof Replacement (Hour by Hour)

The night before a roof replacement, most homeowners have no idea what is about to happen except that it will be loud and expensive. Here is the whole day, hour by hour, the way it actually runs on a typical one-day asphalt job, so nothing that happens tomorrow surprises you.

The short version: materials and dumpster land around 6:30 am, tear-off starts around 7, the deck gets inspected and any bad wood replaced by mid-morning, the roof is dried in with underlayment by lunch, shingles run through the afternoon, details and cleanup finish by early evening. If you want to sanity-check what you are paying for that day, the roof replacement cost estimator shows how size, pitch, and material set the number.

What happens before the crew even arrives?

Around 6:30 am, sometimes the evening before, two deliveries show up. A boom truck places the shingles, often directly onto the roof to save the crew a thousand ladder trips. A roll-off dumpster gets spotted on your driveway, ideally on boards to protect the concrete, close enough to the house that tear-off debris can go more or less straight in.

This is why your cars need to be on the street the night before. Once a dumpster and a material drop block the driveway, a trapped car stays trapped until evening, and I have watched that exact mistake make someone miss a flight.

What does tear-off actually look like?

The crew rolls in around 7 am, and the foreman should walk the job with you for five minutes before the noise starts (your questions for that walkthrough are below). Then tarps go up over landscaping and siding, plywood or mesh goes over windows and AC units in the line of fire, and the crew starts stripping the old roof with tear-off forks and shovels.

This is the loudest, messiest part of the whole project. A competent crew strips a typical house in 2 to 3 hours, working slope by slope so the exposed deck is never bigger than what they can dry in fast if weather moves. Inside, it sounds like the house is being demolished. It is not. But take the pictures off the upstairs walls, because the vibration is real.

What is the mid-morning decking moment?

With the shingles off, the roof deck sits in daylight for the first time in decades, and this is the honest fork in the day: some of that wood may be rotten, delaminated, or soft, especially around old leaks, chimneys, and poorly vented attic areas. No contractor can see through shingles, so no honest bid includes an exact decking number. What it should include is a per-sheet replacement price agreed in writing before the job started.

In many markets that runs somewhere around $80 to $150 per sheet installed, and your contract should state your number. A typical house needs zero to a handful of sheets. A neglected roof can need a lot more. Ask the foreman to photograph every sheet they replace, before and after, and to tell you the running count as it happens rather than presenting a surprise total at dinner time.

What goes on the roof before the shingles?

Late morning is the dry-in, and it is the part of the job your leaks actually care about:

• Drip edge along the eaves, so water leaves the roof into the gutters instead of behind them.
• Ice and water shield, a self-adhering membrane, in the valleys and around penetrations, and along the eaves where codes require it in colder regions. Local code sets the minimum here, so where it goes varies by where you live.
• Synthetic underlayment over the whole deck, the secondary water barrier under the shingles.

By lunch, a one-day job should be fully dried in. That matters because an experienced foreman watches radar all day, and a dried-in roof can take a surprise thunderstorm without your living room finding out.

When do the shingles actually go on?

Early afternoon is when the roof starts looking like a roof. Starter strip goes on at the eaves and rakes, then the field shingles run in overlapping courses, nailed to the manufacturer's pattern. A production crew moves fast here, and fast is fine in the open field of the roof. The middle of a slope is honest work with no secrets.

Where you learn what kind of crew you hired is the slow parts: valleys, chimneys, skylights, walls. Watch whether they slow down there. Speed in the field, patience at the details is the signature of a crew that does not generate callbacks.

What detail work finishes the roof?

Late afternoon goes to the pieces that cause most future leaks, which is why the good crews put their best people on them:

• Step and counterflashing at chimneys and sidewalls.
• New pipe boots on every plumbing penetration (reusing old boots on a new roof is a corner cut you should not accept).
• Ridge vent cut in at the peak, or existing vents replaced, so the attic can breathe. Ventilation is its own silent failure mode, and we wrote up exactly what bad attic ventilation does to a roof.
• Ridge cap shingles to finish the peaks and hips.

While that finishes, the rest of the crew starts cleanup: tarps gathered, gutters cleaned of debris, lawn and beds picked by hand, and the rolling magnet walked over grass, driveway, and street for nails. By 5 or 6 pm on a normal one-day job, the dumpster is full and the crew is gone.

What stretches the job to 2 or 3 days?

• Size and cut-up rooflines. Big roofs and complicated ones (lots of hips, valleys, dormers) carry more surface and slower detail work. You can gauge yours with the roof area calculator.
• Steepness. Past about an 8/12 pitch, everything needs harnesses, toe boards, and more careful movement. Steep work is slower and priced accordingly.
• Multiple tear-off layers. Two layers of old shingles is nearly twice the tear-off and dumpster weight.
• Weather. A dried-in roof waits out rain just fine, but shingling stops. A weather delay mid-job is an inconvenience, not an emergency.
• Decking repairs. A dozen bad sheets adds hours.
• Material. Everything above describes asphalt. Metal and tile are multi-day systems by design, often a week or more, and that is normal, not slow.

How should you prep the house the night before?

• Cars out of the driveway and onto the street.
• Pictures, mirrors, and shelf items off upstairs walls; the hammering shakes them.
• Pets boarded or kept inside in a quiet room; the noise genuinely rattles them, and an open gate plus a scared dog is a bad combination.
• Kids briefed: the yard is off limits until the magnet sweep is done.
• Old sheets or plastic over anything stored in the attic, because tear-off rains dust and grit through every deck gap.
• Flag sprinkler heads, drip lines, pond edges, and fragile plants with marker flags or bright tape so tarps and ladders miss them.
• Leave gates open, and point out the septic tank or drain field location if you have one, so nobody parks a dumpster over it.

What should you ask the foreman at the morning walkthrough?

Five questions, two minutes each:

1. Who is the site lead all day, and what is their cell number?
2. What is the per-sheet decking price, and will you photograph and count replaced sheets with me?
3. Where will materials, the dumpster, and ladders sit, and what gets tarped?
4. What happens if weather moves in mid-job?
5. When do we do the final walkthrough, and will you have photos of the flashing and detail work?

A foreman who answers those five easily is running a real job site. One who bristles at them is telling you something too. If you have not signed yet, the vetting list in how to hire a roofer without getting burned comes first.

What should the final inspection cover?

Do the walkthrough before the crew leaves if daylight allows, with the punch list in hand: straight courses and ridge lines from the street, flashing photos from the roof (you should not climb; their photos are the record), new boots on every pipe, gutters cleaned, tarps gone, magnet sweep done including a second pass where kids and tires go, dumpster hauled or scheduled, and any dinged siding, gutter, or landscaping written down with a fix date. Then the paperwork: your warranty documents (both the manufacturer's and the workmanship warranty in writing), the permit inspection scheduled if your jurisdiction requires one, and the final invoice matching the contract plus any agreed decking sheets.

What to do next

If your job is scheduled: do the prep list the night before, be present for the two walkthroughs, and let the crew work in between. If you are still in the estimate stage, get your independent numbers first (the cost estimator takes two minutes) so the bids have something honest to be compared against, and read the estimate guide before you sign anything. A one-day roof replacement run by a good crew is a loud, controlled, surprisingly boring event. That is exactly what you want.