Metal Roofing (Standing Seam & Corrugated)
Metal roofing encompasses standing seam panels, corrugated sheets, and metal shingle profiles made from steel, aluminum, copper, or zinc. Known for 40–70+ year lifespans, energy efficiency, and superior wind/fire resistance.
Fast Facts
- What Is It?
- Roof covering made from formed metal panels or sheets. Standing seam has concealed fasteners; exposed-fastener profiles include corrugated, R-panel, and 5-V crimp.
- Common Uses
- Residential roofing (all slopes ≥ 3:12), agricultural buildings, commercial/industrial. Low-slope standing seam works down to 1:12.
- Cost Range
- Corrugated/R-panel: $150–$250/square; Standing seam steel: $350–$700/square; Standing seam copper/zinc: $800–$1,500/square installed.
- Durability
- Steel: 40–60 years. Aluminum: 50–75 years. Copper/zinc: 80–100+ years. Warranties vary by coating system.
Specifications
| Property | Value |
|---|---|
| Materials | Galvalume steel (55% Al-Zn), galvanized steel, aluminum (0.032"–0.040"), copper (16–20 oz) |
| Gauge | Residential: 24–26 ga steel; Commercial: 22–24 ga; Premium: 22 ga |
| Panel Width | Standing seam: 12"–18" coverage; Corrugated: 26"–36" coverage |
| Wind Rating | Standing seam: UL 580 Class 90 (up to 160+ mph tested); ASTM E1592 |
| Fire Rating | Class A over approved deck |
| Weight | 50–150 lbs/square (lightest roofing option — 1/4 the weight of asphalt) |
| Coating | PVDF (Kynar 500/Hylar 5000) for premium fade resistance; SMP for economy |
Standing Seam vs. Exposed Fastener
Standing seam panels interlock and clip to the deck, hiding all fasteners. This eliminates exposed screw holes as a leak source and allows thermal expansion without stress. Exposed-fastener panels (corrugated, R-panel) cost 40–60% less but rely on neoprene washers under each screw that can degrade in 15–20 years, requiring re-screwing.
Coating Systems and Color
PVDF coatings (known by brand names Kynar 500 and Hylar 5000) are the gold standard — they resist chalking, fading, and chemical attack for 30–40 years. SMP (silicone-modified polyester) coatings cost less but fade faster, typically warranted for 25 years. Color choice affects energy performance: lighter colors reflect up to 70% of solar heat (Cool Roof rated by ENERGY STAR).
Installation Considerations
Metal roofing can install over existing asphalt shingles with furring strips (check local code). Proper underlayment is critical — high-temperature synthetic underlayment is recommended over standard felt because metal amplifies heat. Ensure adequate ventilation to prevent condensation on the underside of metal panels.
Frequently Asked Questions
Is metal roofing louder in rain?
Modern metal roofing installed over solid sheathing with underlayment produces noise levels comparable to asphalt shingles. The solid deck and underlayment provide sound dampening. Metal installed over purlins (open framing) without sheathing is noticeably louder.
Does metal roofing attract lightning?
No. Metal roofing does not increase the risk of lightning strikes. Metal is non-combustible, so if lightning does strike, a metal roof is actually safer — it disperses the charge over a wide area rather than concentrating it. Insurance companies typically view metal roofs favorably.
Can you walk on a metal roof?
Yes, with caution. Walk in the flat areas between ribs/seams, never on raised seams or ribs. Wear soft-soled shoes. Standing seam is designed for foot traffic during installation and maintenance. Corrugated can dent if you step on the flats. Always follow manufacturer guidelines.
Comparisons Featuring This Material
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