Metal Roof vs. Asphalt Shingles
in North Carolina

How long each one actually lasts

The Metal Construction Association inspected in-service standing seam roofs made from 55% Al-Zn alloy coated steel and concluded that an equivalent roof built today, using best practices, can be expected to last in excess of 60 years [1]. That study looked at unpainted, low-slope roofs, so it is a floor rather than a ceiling for a painted residential roof — but it is a measured figure rather than a marketing one.

For asphalt, the National Roofing Contractors Association is blunt: most new roofs are designed for about 20 years of useful service [2]. Real-world life varies with ventilation, slope, colour and how hard the sun hits the plane in question.

The practical consequence for a homeowner in Burke, Catawba or Caldwell County is that the two products are not really competing over the same period. A shingle roof is a repeat purchase. A metal roof is closer to a one-time one.

Wind: two different measuring systems

This is where most comparisons go wrong. Shingles are rated in miles per hour, under ASTM D3161 and ASTM D7158; D7158 Class D, G and H correspond to ultimate design wind speeds of 115, 150 and 190 mph [4]. Metal panel systems are rated in uplift pressure — pounds per square foot — under UL 580, UL 1897, ASTM E1592 and FM 4471 [3].

You cannot convert one to the other on the back of an envelope, because uplift depends on building height, roof zone and exposure as well as wind speed. What you can do is ask any contractor for the tested assembly they intend to install, and check that the fasteners, clips and panel gauge match the one that was tested. We will put that in writing on request.

Hail, and what a dent actually means

UL 2218 Class 4 — the top class — means a two-inch steel ball dropped from twenty feet does not penetrate the material [9]. Both Class 4 shingles and metal panels over a solid substrate can reach it. The difference is in what failure looks like: a hail-struck metal panel may be dented while the water barrier is intact, whereas a hail-struck shingle can lose granules and shorten its remaining life without looking dramatic from the ground [8].

That distinction matters when you file a claim. In North Carolina, whether a carrier pays actual cash value or replacement cost is set by your policy, not by state law; if you and the carrier agree the loss is covered but disagree on the amount, the appraisal process in N.C.G.S. §58-44-16 is the statutory mechanism for settling it [15]. The state also publishes consumer guidance on homeowners policies [16].

Snow and ice in the higher elevations

If your home is in Boone, Banner Elk, Blowing Rock or anywhere else with real snow load, metal changes the problem rather than removing it. The Metal Construction Association notes that pitched roofs with a slippery surface can pose sliding snow and ice hazards below the eaves, and that snow retention systems are installed on these roofs to reduce the risk of a sudden release and to protect the discharge area below [17]. Budget for snow guards over doorways, walkways and driveways when you price a metal roof at elevation.

Energy and end of life

The Department of Energy and Oak Ridge National Laboratory publish a Roof Savings Calculator that models roughly 10–25% cooling savings for reflective roofing in climate zones 1–3 [12]. Much of North Carolina sits at the cooler edge of that range, so treat it as an upper bound rather than a promise.

At the end of its life a metal roof is 100% recyclable and starts with a minimum of 25% recycled content [13]. Asphalt shingle scrap runs to roughly 11 million tons a year in the United States, and the asphalt roofing industry has set a target of cutting landfill disposal in half by 2035 [14].

Where shingles are the right answer

We install both, so we have no reason to pretend otherwise. Architectural shingles make sense when the roof has many small planes, dormers and penetrations that make metal detailing expensive; when a homeowners association or historic district restricts the finish; when the house is being sold shortly and the buyer will not pay for the difference; or when the budget simply is not there this year and the roof needs to be watertight now. A properly installed shingle roof from a major manufacturer, nailed to the published pattern, is a perfectly respectable roof.

Read more on standing seam, corrugated and ag panel, architectural shingles and metal roof replacement.

One North Carolina rule worth knowing

North Carolina requires a licensed general contractor once a project’s value passes the threshold set by the state licensing board [18]. Foothills Metal Roofing operates under Catawba Valley Builders, LLC, NC General Contractor License L.102552. Ask any roofer you are considering for their number, and look it up.