Metal Roof Installation: Complete Step-by-Step Guide (2026)

Before diving into installation, it's essential to understand the main types of metal roofing systems. Each has different installation requirements:

Standing Seam Metal Roofing

Corrugated Metal Roofing

Metal Shingles

R-Panel / PBR Panel

Metal roofing comes in several material options, each with different properties, lifespans, and price points:

Paint/Coating Systems

The coating system protects the metal and determines color longevity:

• PVDF (Kynar 500/Hylar 5000): Premium coating, 30-40 year color warranty, best UV and chalk resistance
• SMP (Silicone-Modified Polyester): Mid-range, 20-25 year warranty, good value
• Polyester: Budget option, 10-15 year warranty, fades faster

Proper preparation is critical for a successful metal roof installation. Here's what needs to happen before the first panel goes up:

Step 1: Roof Deck Inspection and Repair

The roof deck (typically plywood or OSB sheathing) must be:

• Structurally sound: No rot, delamination, or soft spots
• Flat: Warped or uneven areas will telegraph through metal panels
• Properly nailed: Loose sheathing must be resecured
• Correct thickness: Minimum 7/16" OSB or 15/32" plywood recommended

Step 2: Remove Existing Roofing (If Applicable)

Metal roofing can sometimes be installed over existing shingles, but removal is often better:

Step 3: Install Underlayment

Underlayment provides a secondary water barrier and prevents direct metal-to-deck contact:

• Synthetic underlayment: Required for most metal roof installations (30# felt is NOT recommended)
• High-temp synthetic: For metal roofing, use underlayment rated for 240°F+ (metal gets hot)
• Ice & water shield: Required at eaves, valleys, and penetrations in cold climates
• Slip sheet: Some metal roofs require a slip sheet between underlayment and metal

Step 4: Install Drip Edge and Starter Trim

Metal-specific trim components go on before panels:

• Eave trim/drip edge: Channels water into gutters
• Gable trim/rake edge: Finishes roof edges
• Valley flashing: Pre-formed or fabricated for valley areas
• Ridge cap base: Some systems require pre-installed components

Metal roof installation requires specialized tools beyond standard roofing equipment. Here's what you'll need:

Essential Tools

Materials Checklist

• Metal panels: Order 10-15% extra for cuts and waste
• Trim pieces: Eave, gable, ridge, transition, valley
• Fasteners: Panel screws, trim screws, pop rivets
• Sealant: Use manufacturer-approved sealant only
• Underlayment: High-temp synthetic (30# felt NOT recommended)
• Butyl tape: For sealing trim to panels
• Pipe boots: Sized for plumbing vents
• Touch-up paint: Matches panel color for scratches

With preparation complete, here's the actual panel installation process:

Step 1: Establish Starting Point

Metal roofing installation starts at one end of the roof and works across:

• Wind direction: Start on the side opposite prevailing winds so overlaps face away from wind
• Square check: Measure diagonals to ensure roof is square—adjust if necessary
• Reference line: Snap a chalk line parallel to the eave, set back 1-2" for overhang
• Panel orientation: First panel overlapping edge faces away from starting corner

Step 2: Install First Panel

Step 3: Continue Panel Installation

Work across the roof, overlapping panels:

• Overlap direction: Each panel overlaps the previous one (usually one rib)
• Seam sealing: Apply sealant in overlapping seam per manufacturer instructions
• Alignment check: Every 3-4 panels, verify alignment with eave
• Fastener pattern: Follow manufacturer's recommended spacing (typically 12-24" on center)
• Thermal expansion: Don't over-drive fasteners—allow slight panel movement

Step 4: Cut Final Panels to Fit

The last panel in each row usually needs cutting:

• Measure carefully—account for trim overlap
• Use electric shears or nibblers for clean cuts
• File any sharp edges
• Apply touch-up paint to cut edges to prevent rust

Step 5: Install Flashing and Transitions

Flashing is critical for waterproofing transitions:

Step 6: Install Ridge Cap

Ridge cap is the final step, covering the roof peak:

• Install ridge vent if required for ventilation
• Apply closure strips or foam sealant at panel-to-ridge transition
• Install ridge cap starting opposite prevailing wind
• Overlap ridge cap sections 6"+ with sealant in overlaps
• Fasten through caps into structural framing when possible

Standing seam metal roofing has a different installation process than exposed-fastener panels. Here's what's unique:

Clip Attachment System

Standing seam panels attach via clips, not screws through the panel:

• Fixed clips: Used at eaves and ridge—lock panel in place
• Floating clips: Used mid-panel—allow thermal expansion/contraction
• Clip spacing: Typically 12-24" on center per manufacturer specs
• Fasteners: Clips attach to deck with screws—panels never get screwed

Seaming Process

Standing seam panels connect via interlocking seams that get crimped together:

Specialized Equipment Required

• Electric seamer: For field-locked seams (specialized expensive equipment)
• Hand seamers: For detail work around penetrations and edges
• Panel notcher: For cutting panel ends
• Hem tool: For creating panel end hems
• Portable panel former: Some contractors form panels on-site

In our experience, the single biggest source of metal roof leaks is not the panels themselves — it's where the panels meet penetrations. Every pipe, chimney, skylight, and vent that passes through your roof creates a potential leak point that demands meticulous flashing work. I've been called out to fix more "leaky metal roofs" caused by bad flashing than any other issue.

Pipe Boot Flashing

Plumbing vents are the most common roof penetration. For metal roofs, standard asphalt-roof pipe boots won't work — you need boots designed for metal:

• Material: Use EPDM rubber or silicone pipe boots rated for metal roofing temperatures (up to 400°F on dark panels in South Carolina sun)
• Sizing: The boot must fit snugly around the pipe — a 3" pipe needs a 3" boot, not a 4" with sealant filling the gap
• Installation: Cut the metal panel to fit around the pipe with 1/2" clearance, slide the boot over the pipe, and seal the base flange to the panel with butyl tape and screws
• Common mistake: Using a universal boot trimmed to size — these degrade faster than purpose-molded boots

Chimney Flashing: Step and Counter Flashing

Chimneys are the most complex penetration to flash properly on a metal roof. You need two layers of protection:

Skylight Flashing

Skylights on metal roofs need custom-fabricated curb flashing kits. What I see on every job where a skylight leaks:

• Uphill side: A diverter (mini cricket) above the skylight curb to channel water around it
• Sides: Step flashing running the full length of the curb, with panels cut to follow the curb line
• Downhill side: An apron flashing that extends at least 8 inches past the curb onto the panels below
• Sealant: Butyl tape under all flashing-to-metal joints, plus a bead of polyurethane sealant on top as a secondary barrier

Valley Flashing

Valleys concentrate water flow, making them high-risk leak areas. Two methods are used:

One of the most overlooked aspects of metal roof installation is ventilation. I can't tell you how many times we've been called to a "leaking" metal roof only to find the real problem is condensation from inadequate ventilation. Here in the Myrtle Beach area, where humidity regularly exceeds 80%, proper ventilation isn't optional — it's critical.

Why Metal Roofs Need Ventilation

Metal is a thermal conductor, which means it heats up fast and cools down fast. When warm, moisture-laden air from inside your home hits the cool underside of a metal roof, condensation forms — just like water droplets on a cold glass. Without ventilation to carry that moisture away, you get:

• Deck rot: Persistent moisture breaks down OSB and plywood sheathing from above
• Mold growth: Dark, moist spaces under the roof become mold breeding grounds
• Insulation damage: Wet insulation loses R-value and can compress permanently
• Fastener corrosion: Condensation on fastener points can cause premature rust, even on coated screws
• Ice damming (in cold climates): Though less of a concern in SC, uneven roof temperatures cause ice buildup

Types of Ventilation for Metal Roofs

Code Requirements: IRC R806

The International Residential Code (IRC) Section R806 governs attic ventilation and applies to metal roofs in South Carolina:

Coastal Humidity: Myrtle Beach Considerations

In Myrtle Beach and the Grand Strand, ventilation is especially critical. Our average relative humidity hovers around 73% year-round, with summer months regularly exceeding 85%. What I recommend for every coastal metal roof installation:

• Exceed code minimums: I recommend 1:100 ventilation ratio in coastal SC rather than code-minimum 1:150 — the extra airflow handles our humidity
• Continuous soffit vents: Individual soffit vents can't keep up. Use continuous perforated soffit panels for maximum intake
• Above-deck ventilation gap: A 1" airspace between metal panels and underlayment using battens or ventilation strips reduces condensation dramatically
• Vapor barriers: In our climate zone, install a vapor retarder on the conditioned (warm) side of ceiling insulation to prevent interior moisture from reaching the attic

Ventilation and Energy Efficiency

Proper ventilation works hand-in-hand with metal roofing's energy benefits:

• Summer cooling: Ridge and soffit ventilation moves hot air out of the attic, reducing cooling loads by up to 30% when combined with metal's reflective properties
• Radiant barrier synergy: Metal roofing plus a radiant barrier in the attic plus proper ventilation is the most efficient roof assembly for South Carolina's climate
• Lifespan extension: Ventilated metal roofs experience less thermal cycling stress on fasteners and sealants, extending the functional life of every component

One of the most common questions homeowners ask me is whether they can install metal roofing directly over their existing asphalt shingles. The short answer: sometimes yes, sometimes absolutely not. Getting this decision wrong can cost you thousands and void your warranty. Here's how to decide.

When Overlay Installation Works

Metal-over-shingle installations can work well under the right conditions:

When Tear-Off Is Required

Overlay vs. Tear-Off: Comparison

The Moisture Trap Problem

This is the risk that concerns me most with overlay installations. Here's what happens:

Our Recommendation

In our experience working across the Myrtle Beach area, we recommend tear-off for about 80% of residential metal roof installations. The additional cost is modest compared to the total project investment, and the peace of mind of knowing your deck is sound and your warranty is intact is worth it. The only overlay installations we feel confident about are homes with verified single-layer shingles in excellent condition, a sound deck confirmed by attic inspection, and a proper batten system for ventilation. When in doubt, tear it off. Call us at (843) 877-5539 and we'll inspect your existing roof and tell you honestly whether overlay is viable for your home.

Metal roofing is unforgiving of mistakes. Here are the most common errors and how to prevent them:

Should you install your metal roof yourself or hire professionals? Here's an honest comparison:

When DIY Might Work

When to Hire Professionals

DIY vs Professional Comparison

Metal roof installation costs vary significantly based on your roof size, material choice, system type, and project complexity. Rather than publishing specific prices that may not reflect your situation, here is what affects your investment:

Relative Cost by Roofing Type

Factors That Affect Cost

What's Included in Professional Installation

• Removal and disposal of existing roofing (if applicable)
• Inspection and repair of roof deck
• Installation of underlayment and ice/water shield
• All trim pieces (eave, gable, ridge, valley)
• Flashing at walls, penetrations, and transitions
• Metal panels and fasteners
• Pipe boots and vent covers
• Cleanup and debris removal
• Workmanship warranty (typically 2-10 years)
• Permit acquisition and final inspection

Understanding the timeline helps you plan around your metal roof installation:

Pre-Installation (1-4 Weeks Before)

• Week 1-2: Initial consultation, roof measurement, estimate
• Week 2-3: Contract signing, deposit, permit application
• Week 3-4: Material ordering (custom colors may take longer)
• Week 4: Materials arrive, scheduling confirmed

Installation Day-by-Day

Average Timeline by Roof Size

Installing metal roofing in Myrtle Beach and the Grand Strand requires special considerations for salt air, hurricanes, and local building codes:

Material Selection for Coastal Areas

Hurricane/Wind Resistance Requirements

South Carolina coastal building codes require metal roofing to meet specific wind ratings:

• Wind speed rating: Minimum 140 mph in most Horry County areas
• Fastener spacing: Closer spacing in high-wind zones (6-12" at edges)
• Edge metal: Continuous edge metal required, properly fastened
• Clip spacing: Standing seam clips spaced 12" maximum in wind zones
• Seam type: Mechanical-lock seams preferred over snap-lock

Salt Air Maintenance

Even aluminum roofing benefits from periodic maintenance in coastal areas:

• Annual rinse: Wash roof with clean water to remove salt deposits
• Bi-annual inspection: Check fasteners, sealant, and trim for corrosion
• Immediate repair: Address any scratches or coating damage promptly
• Gutter maintenance: Keep gutters clear to prevent salt water pooling

Insurance Benefits in Coastal SC

Metal roofing often qualifies for insurance discounts in hurricane-prone areas:

• Wind mitigation discount: Metal roofs meeting 140+ mph rating can qualify
• Impact resistance: Some metal roofs are Class 4 impact rated
• Fortified certification: Additional discounts with IBHS Fortified designation
• Typical savings: 10-30% reduction in wind/hurricane coverage premium

One of the biggest selling points of metal roofing is its longevity — 40 to 70 years depending on the material. But "low maintenance" does not mean "no maintenance." In our experience, the homeowners who get the full lifespan out of their metal roof are the ones who do basic inspections and upkeep on a predictable schedule. Here's the maintenance plan I give every customer after we complete their installation.

Annual Inspection Checklist

Once a year — ideally in late fall before winter storms in the Grand Strand — walk around your home and check for:

Seasonal Maintenance for Coastal South Carolina

Long-Term Replacement Schedule

While the metal panels themselves can last 50+ years, some components have shorter lifespans. Plan for these replacements:

• Sealant and caulk (8-12 years): All sealant at joints, penetrations, and overlaps needs periodic replacement. Budget for a professional re-seal every decade
• Rubber pipe boots (15-20 years): EPDM boots degrade in UV and coastal conditions. Silicone boots last longer but still need monitoring
• Closure strips (15-20 years): Foam closure strips at ridge and eave compress and deteriorate over time, potentially allowing pests and moisture
• Exposed fastener washers (20-25 years): The EPDM washers on exposed screws dry out and crack. Plan for a fastener re-drive and washer replacement at this interval
• Touch-up paint (as needed): Address scratches and exposed metal promptly. Manufacturer touch-up paint costs very little but prevents localized corrosion
• Coating refresh (25-40 years): PVDF coatings last 30-40 years, but you may want to refresh color with a specialty metal roof coating system

Signs Your Metal Roof Needs Professional Attention

Metal roofing installation requires specialized skills different from general roofing. Here's how to find the right contractor:

Must-Have Qualifications

• Metal roofing experience: At least 5 years installing metal, not just "roofing"
• Manufacturer certification: Certified by the panel manufacturer (e.g., Sheffield Metals, McElroy, ATAS)
• Proper licensing: SC residential/commercial roofing license (verify at llr.sc.gov)
• Insurance: Workers' comp and liability coverage (get certificates)
• Local references: Metal roofs they installed 5+ years ago still performing

Questions to Ask Contractors

Red Flags to Watch For