Roof Replacement Process: Step-by-Step Guide (2026)

How Roof Replacement Actually Works

The average roof replacement takes 1 to 3 days for a standard residential home. But the full process, from first measurement to final inspection, follows a specific sequence that every homeowner should understand before signing a contract. An estimated 5 million homes in the US get a new roof every year, and yet most homeowners go in blind.

This guide walks you through each phase so nothing catches you off guard. If you want to understand your costs first, get your instant estimate before reading on.

Step 1: Roof Measurement and Estimate

Every roof replacement starts with measuring the roof. Traditional contractors send someone to your house, climb on the roof, and hand-measure. This takes 1 to 2 hours and introduces human error. SquareDash uses satellite imagery to measure your roof remotely with 98.5% accuracy in under 30 seconds.

The measurement determines how many roofing squares your project requires. One roofing square is 100 square feet. The average US home has 20 to 25 squares.

Step 2: Material Selection

Once the measurement is done, you choose your materials. The most common options are:

• Architectural shingles (chosen by 80%+ of homeowners) - see our architectural vs 3-tab comparison
• 3-tab shingles (budget option, 25-30 year lifespan)
• Impact-resistant shingles (Class 4, ideal for hail-prone regions)
• Metal roofing - see our metal vs shingles guide

SquareDash uses Owens Corning materials exclusively as a Platinum Preferred contractor. This guarantees consistent quality across every job.

Step 3: Permits and Scheduling

Most municipalities require a roofing permit before work begins. The average permit costs $150 to $500 depending on your location. SquareDash handles all permitting as part of the all-inclusive price. Traditional contractors sometimes skip permits, which can create problems when you sell the home.

Step 4: Tear-Off

On installation day, the crew starts by stripping the old roofing material down to the decking. This process is called tear-off. For a detailed comparison of tear-off versus overlay, see our overlay vs tear-off guide. Full tear-off is the industry best practice because it exposes the decking for inspection.

Step 5: Deck Inspection and Repair

With the old shingles removed, the crew inspects every sheet of plywood decking. According to industry data, approximately 15% of roof replacements reveal decking damage that needs repair. Rotted or soft plywood is replaced before anything new goes on top. SquareDash includes a decking repair allowance in every quote.

Step 6: Underlayment and Ice Shield

Synthetic underlayment is rolled over the entire deck as a secondary water barrier. In cold climates, ice and water shield is applied along eaves and valleys to prevent ice dam leaks. This layer is critical and should never be skipped.

Step 7: Shingle Installation

Shingles are installed from the bottom of the roof up, overlapping in courses. Starter strips go on first, then field shingles, then ridge caps at the peak. Proper nailing patterns (4 to 6 nails per shingle, depending on wind zone) are essential to meeting warranty requirements.

Step 8: Flashing, Vents, and Trim

New flashing is installed around chimneys, skylights, and wall junctions. Drip edge goes along every roof edge. Ridge vents and ventilation components are installed or replaced as needed.

Step 9: Cleanup and Final Inspection

The crew runs magnetic sweeps across the yard and driveway to pick up stray nails. All debris is loaded into dumpsters. A final walkthrough confirms every detail meets specifications. Many municipalities also require a post-installation inspection before closing the permit.