# Stainless Steel Roofing

> Stainless steel roofing uses chromium-alloyed steel sheet, either bare or tin-coated, for long-life standing seam, seamed or shingle roofs.

- URL: https://roof.wiki/stainless-steel-roofing/
- Topic: Roofing Materials
- Also known as: stainless steel roof; inox roofing
- Regions: Global
- First published: 2026-11-02 · Last reviewed: 2026-11-02
- Cite as: "Stainless Steel Roofing." roof.wiki. https://roof.wiki/stainless-steel-roofing/

## Key facts

- **Defining alloy content:** At least 10.5% chromium
- **Typical grades in roofing:** 439 (inland), 316L (coastal), 304/300-series fasteners
- **Thermal expansion (304):** About 17.3 x 10^-6/K (9.6 x 10^-6/F)

Stainless steel is iron alloyed with 10.5% or more chromium. The chromium forms a thin, self-healing passive film, so the metal does not need a zinc or paint coating to resist rust. In roofing it is used for roll-formed standing seam panels, traditional hand-seamed roofs, individual shingles, gutters and flashings, and very widely for fasteners and concealed cleats.

## Grades and finishes

Different grades suit different exposures. For tin-coated (terne-coated) stainless roofing, ferritic grade 439 is used in normal environments and the molybdenum-bearing austenitic grade 316L near the coast, where chlorides are a concern. Tin-coated versions weather to a soft matte grey.

## Behaviour on the roof

- **Thermal movement**: austenitic grades such as 304 expand about 17 x 10^-6 per degree C (about 9.6 x 10^-6 per degree F), noticeably more than carbon steel, so long panels need clips that allow sliding.
- **Galvanic position**: stainless is close to copper on the galvanic scale, so 300-series stainless fasteners are the usual choice with copper roofing, but stainless will accelerate corrosion of zinc, galvanized steel or aluminium in contact with it in wet conditions.

## Use in restoration

Stainless is also the base metal of terne-coated stainless, the common replacement for historic terne roofs.

## Sources

1. Terneplate — Wikipedia. https://en.wikipedia.org/wiki/Terneplate
2. Busting 5 Metal Roofing Myths — RoofersCoffeeShop. https://www.rooferscoffeeshop.com/post/busting-5-metal-roofing-myths-2
3. Coefficients of Linear Thermal Expansion — The Engineering ToolBox. https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html
4. Galvanic corrosion — Wikipedia. https://en.wikipedia.org/wiki/Galvanic_corrosion
5. Stainless steel — Wikipedia. https://en.wikipedia.org/wiki/Stainless_steel