The Roof Replacement Process: Step by Step

A roof replacement is a significant investment — typically $10,000–$18,000 for a standard residential home. Understanding exactly what happens at each stage helps you evaluate contractor quality, recognize when something is being skipped, and have informed conversations throughout the process. Here's the complete process, in order.

Phase 1: Inspection and Estimate

Step 1: Professional Roof Inspection

A thorough pre-replacement inspection assesses the full scope of work needed — not just the shingle surface but the condition of the deck, all flashings, pipe boots, ventilation, fascia, and gutters. This inspection determines:

• Number of existing shingle layers (affects tear-off scope)
• Estimated percentage of decking that needs replacement
• Flashing condition — what can be reused vs. replaced
• Ventilation adequacy — whether upgrades are needed to meet code or manufacturer warranty requirements
• Accurate square footage measurement

Step 2: Written Estimate with Full Scope

A complete estimate specifies:

• Exact shingle product (brand, model name, color) with UL and wind rating noted
• Underlayment specification (felt or synthetic; IWS at eaves and valleys)
• Tear-off scope (one or two layers; includes disposal)
• Decking replacement price (per sheet, with an estimate of expected replacement area)
• All flashing details — which are new vs. reused
• Pipe boot replacement (yes/no; product type)
• Drip edge (new drip edge should always be included)
• Ridge cap specification
• Permit (yes/no; who pulls it)
• Warranty terms — manufacturer product warranty and contractor workmanship warranty
• Payment schedule

Phase 2: Contract and Scheduling

Step 3: Contract Review and Signing

Review every line of the written contract against the estimate. Discrepancies between the verbal estimate/quote and the written contract are a red flag. Confirm: payment schedule (no more than 30% deposit), start date, timeline, and warranty terms are all in the written document.

Step 4: Permit Application

In most jurisdictions, the contractor pulls the permit. This triggers the local building department's inspection process — an independent inspection of the installed work. Permit inspections catch installation errors before they're covered up. Never agree to skip the permit.

Step 5: Material Order and Delivery

Materials are ordered after contract signing and typically delivered 1–5 days before installation. The shingle delivery is a good quality-check moment: verify the product matches your contract (check the wrapper label for brand, product name, and color) and note any damage from delivery.

Phase 3: Installation Day(s)

Step 6: Site Preparation

The crew protects your property before starting: tarps over landscaping and HVAC equipment adjacent to the work area, and positioning of trailer or dumpster for tear-off debris. Your driveway will be in use — vehicles should be moved.

Step 7: Tear-Off

Existing shingles, underlayment, and (if needed) second layers are removed and disposed of. This exposes the deck for inspection. A thorough tear-off includes removing all old flashings — pipe boots, drip edge, and accessible step/counter flashings — not just the shingles.

Step 8: Deck Inspection and Repair

With the deck exposed, the crew inspects every section for soft spots, rot, delamination, or damage. This is the only opportunity in the project cycle to repair the deck without removing new material. Affected sections are cut out and replaced with new OSB or plywood to match the existing thickness. The per-sheet price should be in your contract — budget for 5–15% replacement on most homes, more on older homes with any known leak history.

Step 9: Ice and Water Shield Installation

Before any other material goes on, IWS is installed at all eaves (minimum 3–4 feet, more in cold climates) and all valleys (full length). This is your last opportunity to verify IWS is being installed before it's covered. It's worth watching this step if you're home.

Step 10: Underlayment Installation

Synthetic or felt underlayment covers the remaining deck area not covered by IWS. This provides secondary protection during installation (if rain interrupts the job) and as a backup barrier behind finished shingles. Synthetic is preferred for its durability and water resistance.

Step 11: Drip Edge Installation

New drip edge is installed at eaves and rakes. The installation sequence matters: at eaves, drip edge installs under the underlayment (water runs off drip edge into gutter, not behind it); at rakes, drip edge installs over the underlayment. Incorrect sequence is a common installation error.

Step 12: Flashing Installation

All flashings are installed before or concurrent with shingle installation in the relevant areas: step flashing at walls and dormers (integrated course-by-course with shingle installation), valley metal or flashing in valleys, and chimney base flashing. Counter flashing at chimneys is often done after shingles if it involves masonry work.

Step 13: Starter Strip Installation

Pre-adhesived starter strip is installed at eaves and rakes before the first course of shingles. This provides the adhesive seal for the bottom edge of the first shingle course — the most wind-vulnerable edge of the roof. Skipping starter strip or using cut shingles instead is a quality-cut shortcut.

Step 14: Shingle Installation

Shingles are installed from the eave upward in overlapping courses. Key installation quality points:

• Nails placed in the manufacturer's specified nailing zone (not above or below)
• Nail depth: flush with the shingle surface, not overdriven or underdriven
• Exposure (the visible face dimension) consistent with manufacturer specification
• Staggered butt joints between courses (no vertical seam alignment)
• Four or six nails per shingle per specification (high-wind markets: six)

Step 15: Pipe Boot and Penetration Flashing

New pipe boots are installed around all vent pipe penetrations as shingle courses reach each pipe. New rubber-collar boots are specified; confirm lead or aluminum boots if available as they outlast EPDM rubber collars significantly.

Step 16: Ridge Cap Installation

Ridge cap shingles are installed along the ridge and all hip lines. Proper ridge cap has the correct nailing depth and is sealed at the end cap. Hip-and-ridge shingles (purpose-made bent pieces) are correct; cut three-tab shingles used as ridge cap is an inferior substitution.

Step 17: Final Cleanup

A thorough cleanup includes:

• All debris removed from roof surface, gutters, and ground
• Magnetic sweeps of the driveway, walkways, and lawn for fallen nails
• Removal of all protection tarps and equipment
• Final walk-around with homeowner

Phase 4: Post-Installation

Step 18: Permit Inspection

The local building inspector visits to inspect the completed installation against code requirements. This is independent verification that the work meets local standards. Ask your contractor to notify you when the inspection is scheduled and what the result was.

Step 19: Manufacturer Warranty Registration

Register the manufacturer warranty within the specified window (typically 30–60 days of installation). Most manufacturers require online registration; your contractor should provide you with the product information needed to complete this. Don't skip this step — an unregistered warranty has reduced coverage.

Step 20: Insurance Premium Discount Submission

If you installed Class 4 IR shingles, submit the UL 2218 certification sheet and installation documentation to your insurer to activate the premium discount. Do this within 30 days of completion. This step is often forgotten — it represents hundreds of dollars per year in premium savings.

Ready to start? Get a free inspection and written estimate with full step-by-step scope documentation. (800) 555-0100.