Roofing Installation Order of Operations: Step-by-Step Guide

Replacing or installing a roof requires a clear, methodical sequence to ensure safety, longevity, and warranty compliance. This guide outlines the typical roofing order of operations used by professionals, breaking each phase into actionable steps, common checks, and quality-control points to help homeowners, contractors, and project managers plan and inspect roofing work effectively.

Phase	Key Tasks	Purpose
Pre-Installation	Inspection, measurements, permits	Assess condition & secure approvals
Preparation	Remove old roofing, deck repair	Create a sound substrate
Underlayment & Flashing	Install felt/synthetic, flashing	Waterproof critical areas
Shingle/Panel Installation	Lay roofing material, ridge work	Provide final weather barrier
Finishing	Cleanup, inspection, warranty	Ensure performance & compliance

Pre-Installation Assessment And Planning

Before any physical work begins, a thorough inspection and planning phase is essential. Inspect the existing roof structure, attic ventilation, and deck condition to identify rot, insulation issues, or structural concerns that affect scope and cost.

Accurate measurements and material takeoffs determine quantities and help avoid delays. Confirm roof pitch, square footage, valleys, penetrations, and eave lengths to select appropriate materials and flashing types.

Check local building codes and HOA rules, and obtain necessary permits. Permits and code compliance protect the homeowner and prevent costly rework later.

Site Preparation And Safety Setup

Proper site preparation reduces hazards and protects property. Install safety anchorage, guardrails, and ensure fall protection gear is ready. Establish a debris-drop zone and protect landscaping with tarps and plywood.

Coordinate delivery staging for shingles, underlayment rolls, and equipment. Position dumpsters and material piles to minimize lifting distances and reduce trip hazards.

Removal Of Existing Roofing (Tear-Off)

Tear-off can be single or multi-layer depending on local codes and substrate condition. Remove shingles, underlayment, and flashing down to the deck. Inspect and mark deck areas needing repair during tear-off.

Segregate and dispose of materials per local regulations. Document the process with photos to support warranty or insurance claims.

Deck Repair And Structural Corrections

After tear-off, assess the roof deck for rot, missing sheathing, or structural issues. Replace damaged plywood or OSB sections and reinforce framing if necessary. Maintain a smooth, continuous substrate free of protruding nails or gaps.

Verify that roof framing meets load and fastening requirements. Address sagging areas or rafter issues before continuing to underlayment.

Underlayment Installation

Underlayment acts as the secondary water barrier and affects shingle performance. Choose between asphalt-saturated felt or synthetic underlayment based on manufacturer recommendations and climate. Install underlayment horizontally from the eave to the ridge with proper overlaps.

Use ice and water shield in eaves, valleys, and around penetrations for enhanced protection. Apply a self-adhering membrane at vulnerable areas to prevent infiltration during ice dams or wind-driven rain.

Flashing Installation And Penetration Sealing

Flashing is critical to waterproof transitions and penetrations. Install step flashing at roof-to-wall interfaces, continuous flashing at chimneys, and base flashing at skylights. Ensure flashing integrates underlayment and siding to create a shingled water-shedding pattern.

Seal pipe boots, roof vents, and skylight junctions with compatible materials. Use metal flashing for long-term durability at chimneys and valleys.

Starter Strips, Drip Edge, And Eave Work

Install drip edge along eaves and rakes before underlayment where required, or over underlayment per local practice. Apply starter strips to the eave to lock first course shingles and reduce blow-off risk. Proper eave termination prevents water infiltration under the first shingles.

Shingle Or Roofing Material Installation

Follow the manufacturer’s pattern and fastening schedule closely for the chosen roofing material. For asphalt shingles, work from the eave toward the ridge, aligning courses and maintaining consistent exposure. Use correct nail type, placement, and count to meet wind warranties.

For metal panels, tiles, or membrane systems, adhere to specific overlap, fastener, and expansion joint requirements. Verify thermal movement and secure panels accordingly.

Valleys, Ridges, And Hip Treatments

Valleys require special attention: open vs. closed valley details differ by material and aesthetic. Install valley flashing and seat shingles or metal appropriately to channel water away. Ensure continuous, watertight valley assembly.

Ridge caps and hip shingles should be installed to allow ventilation where ridge vents are used. Confirm ridge ventilation is adequate for attic performance and that caps are fastened per manufacturer guidance.

Ventilation And Attic Considerations

Effective attic ventilation balances intake at the soffit with exhaust at the ridge or turbines to control moisture and heat. Calculate net free vent area based on attic square footage and insulation levels.

Address bathroom or kitchen exhaust fans and ensure they terminate outside the attic. Blocked or inadequate ventilation shortens roof life and increases energy costs.

Gutters, Downspouts, And Flashing Integration

Coordinate gutter and downspout installation with eave detail to prevent water backup. Install gutter guards or leaf protection where appropriate. Ensure flashing directs water into gutters without bypassing the eave edge.

Confirm downspout discharge points protect foundations and landscaping. Extend downspouts or install splash blocks to manage roof runoff.

Final Inspection And Quality Control

Perform a systematic inspection covering fastener placement, flashing terminations, underlayment overlaps, and ventilation. Use a checklist that mirrors manufacturer and code requirements to ensure no critical items are missed.

Document completion with photos and provide the homeowner with care instructions, warranty paperwork, and contact information for follow-up. Verify that all roof penetrations and flashings are watertight before crew demobilization.

Cleanup, Waste Disposal, And Post-Job Communication

Remove all debris, nails, and leftover materials from the property and surrounding areas. Check gutters, landscaping, and driveway for stray nails using a magnetic sweeper. Proper cleanup reduces liability and increases customer satisfaction.

Conduct a final walkthrough with the homeowner or property manager to explain the work performed and maintenance tips. Provide clear documentation on warranty terms and routine inspections.

Common Problems And How The Order Prevents Them

Improper sequence leads to leaks, premature failure, or voided warranties. For example, installing shingles before proper flashing can cause persistent leaks. Following the established order mitigates the most common failure modes.

Skipping deck repairs or underlayment upgrades often shortens roof life. Address substrate and ventilation issues early to avoid costly callbacks.

Checklist For Homeowners And Inspectors

Homeowners and inspectors can use a concise checklist to verify critical steps were completed: permit presence, tear-off depth, deck repairs, underlayment type, flashing locations, fastener count, ventilation, and cleanup. Request photographic documentation for each major phase.

• Pre-Installation: Inspection report and permit copies
• Tear-Off: Photos of deck condition
• Underlayment & Flashing: Product documentation and installation photos
• Final: Punch-list completion and warranty packet

Costs, Timelines, And Weather Considerations

Project costs depend on material choice, roof complexity, and repairs; tear-off and decking replacement increase labor and disposal fees. Obtain multiple bids and detailed scopes to compare apples-to-apples.

Weather impacts scheduling and material performance; avoid installation during high humidity or immediate storms. Plan for buffer days to accommodate weather delays and protect the structure with tarps if work is interrupted.

How To Use This Guide With Contractors

Share the order-of-operations checklist with contractors to set expectations and contract terms. Include milestones and inspection points in the contract to verify compliance. Require contractor proof of licensing, insurance, and product warranties.

Consider retaining a third-party inspector for high-value or complex projects. Independent inspection can catch overlooked defects before final payment.

Additional Resources And Manufacturer Requirements

Consult shingle, membrane, and metal manufacturers for installation bulletins and warranty conditions that may alter the sequence. Manufacturer guidelines trump generic sequences when securing product warranties.

Local building departments and professional associations (e.g., NRCA) provide code and best-practice resources. Use trusted sources for the most current recommendations.