A roof replacement on an average home takes one to three days once work begins — but the full process from first call to final permit spans several weeks. Homeowners who understand what's supposed to happen at each stage are far better positioned to spot corner-cutting, ask informed questions, and verify they received what they paid for. Here's every step.
The 14-Step Roof Replacement Process
Initial Inspection (Pre-Contract)
A thorough contractor inspects both the exterior roof and the attic before writing any estimate. On the roof: shingle condition, granule loss, flashing integrity, ridge and hip condition, penetrations. From the attic: decking condition, ventilation adequacy, signs of existing leaks or moisture damage. Good contractors document this with photos and share the inspection report. If a contractor skips the attic, that's a meaningful gap — attic conditions affect warranty validity and can reveal hidden problems that change the scope significantly.
Estimate and Contract
A legitimate estimate is line-itemized: materials (shingle type, underlayment, ice shield), labor, decking replacement allowance (stated as a per-sheet price if unknown until tear-off), disposal, and permit fees. The payment schedule should not require more than 10–20% upfront; requiring 50% or full payment before starting is a warning sign. Confirm the contract explicitly states who pulls the permit and who is responsible for cleanup.
Permit Application
Your contractor applies for the building permit through the local municipality — typically 1–5 business days. You should receive the permit number before work begins, and the permit card should be posted visibly at the job site during installation. If a contractor tells you a permit isn't required or suggests skipping it to save money, refuse. Without a permit, the city inspector never signs off, which creates complications for insurance claims and future resale.
Material Delivery
Materials arrive 1–2 days before installation begins — pallets of shingles, rolls of underlayment, ice shield, and hardware. Verify the delivered shingles match what's in your contract (manufacturer, line, color, and bundle count). Shingle pallets will sit on your lawn, driveway, or roof. Move any vehicles, cover decorative landscaping, and warn neighbors about delivery trucks. The dumpster, if used, typically arrives the same day as materials.
Day of Installation — Tear-Off
The crew strips all existing roofing down to the bare deck. This is the noisiest phase — expect several hours of prying and hammering. Multiple layers of old roofing must be removed before new installation can begin (layering over is not code-compliant in most jurisdictions and voids manufacturer warranties). The debris is loaded into the dumpster as it comes off. Expect some granule runoff into landscaping and gutters; this is normal.
Deck Inspection
With the deck fully exposed, the contractor walks every square foot checking for soft spots, rot, delamination, or previously repaired damage. This is a critical phase. Any decking that needs replacement should be photographed, documented, and priced before proceeding — and the contractor should call you for approval before replacing any sheet not included in the original contract. Typical rate: $70–$100 per 4×8 sheet of OSB or plywood. Do not let the crew proceed past this step without a clear accounting of any scope changes.
Underlayment and Ice and Water Shield
Ice and water shield (self-adhering membrane) goes down first in the following locations: all eaves (first 3–6 feet depending on climate zone and local code), all valleys, and around all penetrations (pipe boots, skylights, HVAC units). In high-snow climates, eave coverage extends to 24 inches past the interior wall line. Synthetic underlayment then covers the remaining deck above the ice shield.
Drip Edge
Drip edge is L-shaped metal trim that directs water off the roof deck into the gutter. Installation order matters: at the eaves, drip edge installs under the underlayment. At the rakes (sloped sides), drip edge installs over the underlayment. Getting this order wrong causes water infiltration. This is a detail to ask about specifically if you're present during installation.
Starter Strip and Field Shingles
Starter strip (either factory-produced or cut from 3-tab shingles) goes along the eave and rake edges. Field shingles then install from the bottom up in a specific offset pattern, with each course overlapping the one below. Manufacturers specify both the nail count (typically 4–6 nails per shingle) and the nail placement zone printed on each shingle. Nails driven above the nail zone, or at an angle, reduce the shingle's wind resistance rating and are a workmanship issue.
Flashing
Flashing is the metal (typically aluminum or galvanized steel) that seals transitions and penetrations. Step flashing goes at all wall-to-roof intersections, cut in individual pieces interwoven with each shingle course — this is not caulk, it's physical metal. Counter-flashing at the chimney anchors step flashing to the masonry. New pipe boots (rubber or metal) replace old ones around every plumbing vent penetration. Reusing old, degraded flashing is a common shortcut that leads to early leaks.
Ridge Cap
The ridge receives a dedicated ridge cap product — either a special hip and ridge shingle (thicker, pre-cut) or a ventilated ridge vent system topped with cap shingles. If your attic relies on ridge vents for ventilation, a ventilated ridge cap is non-negotiable — replacing it with solid ridge cap would close off your exhaust ventilation entirely and risk voiding your manufacturer warranty.
Cleanup
A professional crew runs a rolling magnetic nail sweeper (and often hand-magnets) across the entire property including lawn, driveway, and landscaping areas. The dumpster is removed. Gutters are cleared of debris. Any damaged landscaping from equipment is typically noted and addressed. Do a personal walk of the property after the crew leaves — check areas behind shrubs, along fences, and under any deck overhang where nails tend to collect.
Final Permit Inspection
The city or county inspector visits to sign off on the permit. The inspector checks visible elements for code compliance — underlayment, ice shield, drip edge, flashing at accessible points. You don't need to be home. When the inspection passes, the contractor should provide you with the signed permit card. This document confirms that an independent official verified code compliance — keep it in your home records alongside the manufacturer warranty registration.
Warranty Registration
Register your manufacturer warranty online within 30–60 days of installation (check your specific manufacturer's requirement). Your contractor may do this for you — confirm with them, and request the registration confirmation email. Store the registration number, your warranty tier document, and the permit card in the same physical or digital file.
Red Flags to Watch For
- Contractor rushes past the deck inspection without documentation or calling you first
- No permit posted at the job site during installation
- Old flashing being reused on an aged chimney or valley
- Starter strips skipped (shingles installed directly at the edge)
- Layering new shingles over old ones instead of full tear-off
- Final invoice includes a large number of decking sheets you weren't called about
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