Stone-Coated Steel Roofing: How It Compares to Tile and Shingles

Stone-coated steel roofing is made of formed steel panels finished with bonded stone granules so the roof reads as tile, shake or shingles from the street. Whether it beats concrete tile or asphalt shingles on your house comes down to three documents: its impact listing, its wind listing and its weight per square foot, plus a plan for matching panels when one needs replacing.

Standing seam and exposed-fastener panels are covered in metal roofing types, and options beyond metal, tile and shingles in the full roofing materials comparison.

What Stone-Coated Steel Is

Each panel starts as a sheet of steel pressed into a tile, shake or shingle profile. A coating protects the steel, and a layer of stone granules held in a binder gives the surface its texture and color. Steel thickness, the metallic coating, the binder and the granules all vary by maker, and none of them can be judged by eye. Ask for a data sheet that states each one, and ask whether the warranty treats the stone finish and the steel panel separately.

Because the panels are steel, they share metal’s strengths and its weak points: they do not crack the way tile can, but they can dent, and the steel needs its coating intact to resist corrosion.

InterNACHI’s life expectancy chart, which gives guideline ranges for other roof materials, has no row for stone-coated steel. Read the warranty’s separate terms for the steel and the stone finish as the maker’s promise, not as a lifespan.

Compare the three options on the same documents:

Fire classes run from Class A (severe test exposure) through B and C (moderate and light) under ASTM E108, and the class belongs to the tested assembly, so ask for the listing that matches what will be installed.

Weight Compared With Tile and Shingles

Stone-coated steel comes up next to tile because it promises a tile look without tile weight, so the weight claim is the first one to check. Measure it against the ASCE 7-16 dead loads in Boise Cascade’s material-weight reference: 12 pounds per square foot (psf) for concrete roof tile, 6 to 19 psf for clay tile depending on type, and 2 psf for asphalt shingles. The table has no stone-coated steel entry, so the product’s own data sheet is the only number to use.

Apply it in two directions:

• Replacing tile. If the stone-coated product’s data-sheet weight is lower than your current tile, framing load goes down; the questions shift to the deck and how the panels are fastened.
• Replacing shingles. Compare the data-sheet weight with the 2 psf reference for asphalt. If it is heavier than what is on the roof now, the house needs the same framing check any heavier covering would.

If the seller says “lighter than tile” but cannot show a data sheet, treat the claim as unverified.

Hail and Wind: Read the Listing, Not the Brochure

Hail claims are where the sales wording deserves the closest reading. No listing makes a roof hail-proof. A listing tells you the product passed a defined test with a defined projectile.

The two impact tests you will see work differently. UL 2218 drops steel balls on the most vulnerable points of a test assembly, up to a 2.00-inch ball for Class 4 (IBHS lists the sizes in its summary of UL 2218 impact tests). FM Approvals uses ice balls, and in September 2022 it updated FM 4475 for steep-slope roof covers to add Very Severe Hail testing with a 2-inch ice ball. Ask which test the exact panel passed, which class or rating it earned, and get the listing document, not a line from the brochure. Then check that the product name and version on the listing match the product named in your contract, because a maker’s other lines may carry different results.

Hail can still dent steel and knock granules loose without failing a test, and some insurance policies treat dents that change only appearance as cosmetic damage. How dents and cosmetic exclusions work on metal is covered in metal roof facts versus fears.

Wind resistance comes from attachment. FEMA’s Hurricane Ike recovery advisory on metal roof systems in high-wind regions (February 2009) recommends practices for designing and installing metal roofs where wind is severe, and FEMA’s P-499 Fact Sheet 7.6 covers the same subject. Shingle wind classes do not apply to these panels, so ask the maker which uplift test the panel system was listed under, with which fasteners and spacing, and confirm the bid’s attachment matches that listing at eaves, rakes and ridges, where uplift is highest.

Noise and What Sits Under the Panels

The Metal Roofing Alliance, an industry group, says in its myth-busting post that a correctly installed metal roof is as quiet as an asphalt roof. That statement covers metal roofs generally and comes from the industry, so ask the panel maker for any independent noise test on stone-coated panels before you rely on it.

Indoor rain noise depends on what lies between the panel and your ceiling. Ask the installer in writing what goes directly under the panels: the deck, the underlayment, any air space, and whether an insulated attic sits below. A solid deck and insulated attic damp sound; panels over open framing do not. Ask too how the attachment lets the steel expand and contract with temperature, because panels that cannot move freely can tick or creak as they heat and cool through the day.

Repairs: Granule Loss, Scratches, and Foot Traffic

Plan for repairs before you buy, because a stone-coated roof is repaired panel by panel and the new panel has to match.

• Granule loss. Granules can wear or be knocked off over time and after hail, exposing the coating beneath. Ask what the warranty says about granule loss and whether the maker supplies a touch-up material for the stone finish.
• Scratches and cut edges. Where the coating is scratched through or cut, bare steel can rust. Ask how cut edges are treated during installation; finding and treating scratches later is covered in caring for a metal roof’s finish.
• Foot traffic. Panels can dent or lose granules under careless feet. Homeowners should stay off the roof; ask the installer how other trades, such as chimney sweeps, gutter installers or solar crews, should cross it.
• Matching panels. Profile and color can change between production runs. Ask the installer to leave spare panels from the same run, and ask the maker how long it supplies replacements for a discontinued color.

At completion, keep the product name, color name and any lot numbers from the panel packaging, and photograph each roof plane from the ground. Those records make matching easier for a future repair and give you a baseline if you ever need to show storm damage.

Stone-Coated Steel, Concrete Tile, or Shingles?

Work through the conditions that apply to your house:

• If you want a tile look and the framing cannot carry tile, stone-coated steel is a candidate, provided its data-sheet weight fits your framing; judge the tile look from a full-size sample outdoors and an installed roof seen from the street, not from brochure photos. If the framing can carry tile, compare it with clay and concrete tile on the same documents.
• In hail country, compare impact listings under the same test, and ask your insurer in writing how dents to a metal roof would be treated under your policy.
• If wind is your main hazard, keep only the bids that name the uplift listing and the attachment method for every edge.
• If you live near salt water, steel depends on its coating and fasteners. FEMA’s Coastal Building Materials fact sheet (No. 1.7) covers corrosion resistance in material choice, and roofing near the coast applies it to fasteners and metals.
• If your HOA controls appearance, get written approval for the exact profile and color before signing.
• If none of those conditions point to metal or tile, architectural shingles with the wind and impact classes your area needs may be the simpler choice.

Before signing, request five things in writing: the impact-class listing, the wind listing with its attachment method, the data-sheet weight, the fire class of the tested assembly, and the spare-panel and touch-up terms. Leave any bid that cannot supply all five out of the comparison until it does.

This guide is general information for U.S. homeowners, not legal, insurance, tax, or engineering advice. Codes, laws, and policy terms vary by location and change over time; confirm details with your local building department, your insurer, or a licensed professional.

Sources

• Weights of Building Materials (Tech Note GE-1), Boise Cascade Wood Products
• Relative Impact Resistance of Asphalt Shingles: Summary of UL 2218 Impact Tests, Insurance Institute for Business & Home Safety
• Updated Standard: FM 4475, Steep Slope Roof Covers Now Includes Very Severe Hail (VSH) Testing, FM Approvals
• Metal Roof Systems in High-Wind Regions: Hurricane Ike Recovery Advisory, FEMA (listing on DOE Building America Solution Center)
• Facts About Metal Roofing for My Home: Top 10 Myths Busted by MRA, Metal Roofing Alliance
• Coastal Building Materials, FEMA Technical Fact Sheet No. 1.7, FEMA (listing on DOE Building America Solution Center)