The Roof Replacement Process, Step by Step: What Happens and When

The roof replacement process follows the same basic order on most homes. Materials arrive, and the work site gets set up before anything else. Then the old roof comes off one section at a time, and the wood deck gets checked and repaired. Next come the water barrier layers, the flashing and the new shingles or metal panels. The job ends with ridge caps, vents, a full cleanup and a final look at the finished roof.

How long each stage takes depends on your roof, your house and the weather. A large roof, a steep pitch or two old layers of shingles adds tear-off time and labor. Rotted or gappy deck boards add repair work that stays hidden until the old roof is off. Summer storms can pause work for a few hours or even a few days. In Florida, many reroof jobs also stop for a county inspection partway through the work.

Below, we start with what happens before the first old shingle comes off your roof. Then we walk through tear-off and the order in which the new layers go on. Next, we cover what living at home during the job is like, and what can come up mid-job. Last, we explain the final steps and what to check once the crew is done.

Preparing for a New Roof Before Tear-Off Day

Most jobs start with a delivery a day or two before the roofing crew arrives. Many suppliers use a boom truck with a long arm that sets bundles right on the roof. A dumpster or trailer often goes on the driveway to catch the old roofing as it comes off. Crews commonly lay tarps over plants and patios and cover outdoor AC units. Those steps keep falling nails and old shingle grit out of beds and equipment.

Your color choices need to be locked in well before delivery day. That means the shingle color and also the drip edge, vents and any trim metal that shows. Changing your mind after the order ships can push back the start of work. Driveway space, gate widths and soft ground in the yard also shape where trucks and the dumpster can go. Talk through those details with your roofer early, so delivery day goes smoothly.

Check the Color Code on Every Bundle

Shingles of the same color name can vary a little from one batch to the next. GAF says every bundle on a job should carry the same color code. The code is printed on each bundle's wrapper and on the back of each shingle. Mixed codes can show up as patchy, uneven color across a slope once the roof is finished.

• Get the shingle, drip edge and vent color names written on your contract or order.
• Mark sprinkler heads, septic lids and soft spots where trucks should not drive.
• Note where the dumpster can sit without blocking cars, the garage or the mailbox.
• Ask where extra bundles will be stored if they do not all fit on the roof.

How the Old Roof Comes Off and the New Layers Go On

Tear-off strips the old shingles, nails and underlayment down to the wood deck. Many crews work one section at a time, so only part of the roof is open at once. With the deck bare, any loose boards get nailed back down and soft or rotted wood gets cut out. The roof then gets its first water barrier layers, called the dry-in. Many crews strip only as much roof as they can dry in that same day.

The order of the new layers matters as much as the layers themselves. The Asphalt Roofing Manufacturers Association says drip edge goes under the underlayment at the eaves. At the rakes, the sloped side edges of the roof, it goes on top of the underlayment. A sticky, self-sealing leak barrier covers the eaves, the valleys and the areas around openings. Each row of underlayment overlaps the row below it, so water always runs down and off.

• Drip edge along the eaves goes first, set right on the bare wood deck
• Self-sealing leak barrier at the eaves, in valleys and around pipes and chimneys
• Underlayment rolled out from the bottom up, with each new row lapped over the last
• Drip edge on the rakes over the underlayment, then flashing and shingles

What to Expect When Replacing a Roof While You Live There

You can usually stay home during a roof replacement, but it is loud. Tear-off and nailing make steady banging, and the house can shake a little. Dust and old shingle grit can sift into the attic, mostly on older homes with board decks. Keep kids and pets well away from the dumpster area, since debris falls there all day. Parking on the street during the job keeps your cars clear of falling debris and the work zone.

In Florida, a reroof often gets a county inspection partway through the job. Seminole County, for example, lists an in-progress reroof inspection after the old roof is off. The inspector checks deck nailing, flashing and underlayment before they get covered. Osceola County notes that a roof may have to be opened at the end if that inspection was missed. Rules vary by county and state, so ask your roofer who handles the permit and inspections.

When the Old Roof Has Board Decking

Many older homes have decks made of wood planks instead of plywood sheets. IIBEC, a group of building envelope consultants, notes that the boards shrink over the years and gaps open. Those gaps give the new roofing nails less solid wood to grip. Shingle makers commonly call for plywood or OSB sheets over gappy boards, and the framing gets checked for the weight.

• Ask your roofer for photos of the bare deck after tear-off and before dry-in.
• Ask how deck repairs and any board decking overlay will be counted on the bill.
• In Florida, ask when the inspection falls, so you know why work may pause that day.

Final Roof Replacement Steps and Your Walk-Around Check

The last roof replacement steps are the ridge caps, the ridge vent and a check of every flashing. Then the crew hauls off debris, clears the gutters and sweeps for loose nails. Many crews roll a magnet across the yard and driveway to pick nails up. Once they are done, walk around the house with your roofer if you can. Look for straight shingle rows, a neat ridge line and flashing that sits tight at walls and chimneys.

A roof replacement goes smoother when you know the order of the work. Lock in colors early, plan the driveway and expect noise while the crew is on the roof. Ask about the deck once it is bare, and know when an inspection may pause work. At the end, keep the invoice, product names, color code and install date in one folder. GAF says new owners must notify GAF within a set time to transfer its warranty after a home sale.