BuildCompared

Metal Roof vs Shingles

Metal panels can go on much flatter roofs than shingles: the code allows 3:12 for lapped seams without sealant, 1/2:12 with applied lap sealant, 1/4:12 for standing seam, against 2:12 for asphalt shingles.[1] The warranties are built differently. A metal panel warranty covers the steel, for example McElroy's 25 years against rupture, structural failure or perforation, and usually excludes homes near salt water; a shingle warranty covers the shingle, for example GAF's Lifetime limited warranty.[2, 3]

Sources checked How we compare

Metal roof

Standing seam metal roof: long flat panels joined at raised seams
Long panels joined at raised seams

Pick a metal roof if the roof is low-slope (standing seam works from 1/4:12), and the house is outside the coastal distances in the panel warranty.[1, 2, 4]

Asphalt shingles

Architectural shingles: two laminated layers with tabs of different sizes
Laminated asphalt shingles

Pick shingles if the slope is 2:12 or more and you want a warranty that covers wind, algae and manufacturing defects in one document.[1, 3]

At a glance

Metal roofAsphalt shinglesSource
Minimum slope in the code 3:12 for lapped seams without sealant, 1/2:12 with applied lap sealant, 1/4:12 for standing seam 2:12 [1]
Materials in the code Steel galvanized ASTM A653 G90 or aluminum-zinc (Galvalume) ASTM A792 AZ50; aluminum 0.024 inch for roll-formed panels ASTM D3462 [1]
What the warranty covers (examples) McElroy Galvalume: 25 years against rupture, structural failure or perforation GAF: Lifetime; wind 110 mph for 15 years [2, 3]
Coastal limits in the warranty (examples) McElroy: excluded within 1,500 ft of surf, 800 ft of a large bay, 400 ft of marsh; Drexel: at least 2,800 ft from surf, 1,200 ft from a large bay, 600 ft from marshes and canals None in the GAF shingle warranty we read [2, 5]
Fastening Set by the panel system and its evaluation report at least four per strip shingle, or two per individual shingle [1]

Slope

The residential code sets minimum slopes for metal panels by seam type: 3:12 for lapped seams without sealant, 1/2:12 with applied lap sealant, 1/4:12 for standing seam.[1] Asphalt shingles need at least 2:12.[1] So on a low-slope roof, standing seam metal is an option where shingles are not.

Materials

For metal roof panels, the code lists steel with galvanized ASTM A653 G90 or aluminum-zinc (Galvalume) ASTM A792 AZ50, and aluminum of at least 0.024 inch for roll-formed panels.[1] Shingles must meet ASTM D3462.[1]

Warranties, and the coastal fine print

Metal warranties usually cover the metal against perforation for a fixed term: McElroy 25 years against rupture, structural failure or perforation, Drexel 25 years and 6 months against perforation.[2, 5] Both exclude homes close to salt water, with different distances: McElroy excluded within 1,500 ft of surf, 800 ft of a large bay, 400 ft of marsh; Drexel at least 2,800 ft from surf, 1,200 ft from a large bay, 600 ft from marshes and canals. MBCI gives similar guidance for Galvalume, 1,500 ft from surf, 800 ft from a large saltwater bay, 400 ft from saltwater marshes or canals, and 1,000 ft from any body of saltwater for its painted finishes.[2, 4, 5]

GAF's shingle warranty covers manufacturing defects for Lifetime, wind up to 110 mph for 15 years, and algae for 25 years (StainGuard Plus).[3] We found no distance-from-the-coast exclusion in it.

Cost

We are checking the published remodeling cost reports before adding cost figures to this page.

Common questions

Can metal go on a low-slope roof?

Standing seam panels can, from 1/4:12.[1]

Do metal roof warranties apply near the ocean?

Often not. McElroy's Galvalume warranty is excluded within 1,500 ft of surf, 800 ft of a large bay, 400 ft of marsh.[2]

What does a metal roof warranty cover?

Usually the metal itself, for example 25 years against rupture, structural failure or perforation.[2]

Sources

  1. California Building Standards Commission 2025 California Residential Code, Section R905 Requirements for Roof Coverings (effective January 1, 2026). Accessed November 3, 2026.
  2. McElroy Metal Galvalume Limited Warranty (MM602) (Rev. 11/12). Accessed November 3, 2026.
  3. GAF GAF Shingle & Accessory Limited Warranty (RESWT160L) (Form RESWT160L-0426, for installations after January 1, 2025). Accessed November 3, 2026.
  4. MBCI Technical Bulletin 002, Saltwater and Marine Atmospheres (RevB, code 0323). Accessed November 3, 2026.
  5. Drexel Metals DREXLUME 25-Year Limited Warranty (sample) (Revised June 2020). Accessed November 3, 2026.

We did not install or test these products. Everything on this page comes from the documents listed above. If a source changes, numbers here may be out of date until our next check. Spot an error? Email [email protected].