Steel Roofing Panels

Steel is the most common metal roofing material, offering high strength at moderate cost. Roofing steel comes in gauges from 22 (thickest, premium) to 29 (thinnest, economy), with 26-gauge being the residential standard. All roofing steel has a protective coating — either galvanized (zinc), Galvalume (aluminum-zinc alloy), or a combination — topped with a paint system for color and UV protection.

Gauge Selection

Thicker gauges resist denting, span wider purlin spacing, and handle higher wind loads. 24-gauge is premium residential and light commercial — it withstands foot traffic and hail better than thinner options. 26-gauge is standard residential, suitable for most applications. 29-gauge is the minimum acceptable thickness, used mainly for agricultural buildings and budget projects. Avoid 29-gauge for homes — it dents visibly and has limited wind resistance.

Panel Calculations

Measure roof length to determine panel length (panels typically run eave to ridge in one piece, up to 40+ feet). Count panels by dividing roof width by coverage width (36-inch panel with 2-inch overlap = 34 inches of coverage). Add trim pieces separately: ridge cap, eave drip, gable rake, valley flashing, and transition pieces. Trim is sold in 10-foot sections.

Coating and Finish

Paint systems determine how long the color and surface hold up. SMP (silicone modified polyester) is the standard residential paint with a 25-30 year color warranty. PVDF (Kynar/Hylar) is the premium option used on commercial and high-end residential, warranting 35-40 years of color retention. The coating matters more for long-term value than the steel gauge in most climates.