How long roofing materials last

InterNACHI, the International Association of Certified Home Inspectors, estimates that an architectural asphalt shingle roof lasts about 30 years, a metal roof 40 to 80 years and a slate roof 60 to 150 years. For low-slope roofs it gives 15 to 25 years for EPDM rubber and 7 to 20 years for TPO. The trade groups for metal and EPDM roofing publish longer figures for their own products. InterNACHI says its numbers assume regular maintenance and normal wear, and it tells readers to use them only as guidelines.

Estimates by material

The Metal Roofing Alliance speaks for the metal roofing industry, and the EPDM Roofing Association represents the companies that make EPDM membranes and their suppliers. Figures checked October 3, 2026.

Asphalt shingles

Three-tab shingles are single-layer strips cut into three tabs along the bottom edge. Architectural shingles are thicker and laminated. InterNACHI puts the first at 20 years and the second at 30. The Metal Roofing Alliance, which promotes metal as the alternative, says the average asphalt roof lasts 12 to 20 years and that the pitch of the roof and the local climate can shorten that.

InterNACHI lists the conditions that cut asphalt shingle life. It says hot climates drastically reduce it, and roofs in areas with hail and other severe weather may wear out sooner or take isolated damage that needs repair before it spreads to the surrounding shingles. The felt underlayment under the shingles, which the chart calls black paper, carries its own estimate of 15 to 30 years.

The National Roofing Contractors Association (NRCA) says curling or splitting shingles are evidence that an asphalt roof is deteriorating. It says dislodged or missing tabs should be repaired to keep the roof weathertight.

In Conshohocken Borough, a new asphalt roof can go over an old one only in limited cases. The borough’s re-roofing addendum allows no more than two asphalt, fiberglass or low-slope roofing systems, and it requires the old covering to come off when the roof already has two or more layers or is not a sound base. The roofing permits guide covers the permit and the addendum in detail.

Slate

The National Park Service’s Preservation Brief 29, written by architectural conservator Jeffrey S. Levine, ties a slate roof’s life to the quarry the stone came from. It gives Pennsylvania soft-vein slate more than 60 years and Pennsylvania hard-vein slate roughly 100 years. Peach Bottom slate from York County lasts at least 200 years. The brief notes that neither hard-vein nor Peach Bottom slate is still quarried. Vermont and New York slates last about 125 years and Buckingham, Virginia slates 175 years or more. The brief says these spans are a general guide to whether an existing roof is nearing the end of its life.

Slate wears slowly. Paper-thin layers flake off along the stone’s cleavage planes, the natural splitting lines, until the slate turns soft. The brief traces most of this to mineral impurities that react with water through wet and dry, hot and cold cycles to form gypsum. It says slate’s low porosity limits the damage frost does to the stone itself. Pennsylvania ribbon slate, which has bands of impurities, weathers faster than clear slate, according to the brief.

Flashing, the metal that seals joints at valleys, chimneys and walls, often fails first. The brief calls flashings the weakest point in any roof and says metal flashings often wear out before the slate does. It recommends 16-ounce copper as the minimum weight for flashing and heavier copper for gutters and valleys. It also advises using one metal throughout, since mixing metals leads to galvanic corrosion, where one metal corrodes faster when it touches another.

On the choice between repair and replacement, the brief suggests evaluating a roof for repair when fewer than about 20% of the slates are damaged or missing and the roof is otherwise in good shape. Slates sliding out of position can mean the iron nails have corroded while the slates are still sound. The brief says those slates can be salvaged and laid again. Conshohocken’s addendum does not allow a new roof to be installed over slate.

Metal

InterNACHI gives metal roofs 40 to 80 years and copper roofs 70 years or more. The Metal Roofing Alliance tells homeowners to count on 30 to 50 years or more, partly because a metal roof can often be repainted instead of replaced. It says most metal roofs come with a 30 to 50 year warranty. The alliance also says there is little difference between metal and other roofing materials in the noise from rain or hail.

The Park Service’s advice on flashing applies to metal roofs as well. The brief says to use one type of metal for flashings, gutters, downspouts and metal roofs, to avoid galvanic corrosion.

Low-slope roofs

Low-slope roofs, often called flat roofs, are covered with a membrane instead of shingles. EPDM is a synthetic rubber membrane. TPO, short for thermoplastic polyolefin, is a single-ply plastic membrane. InterNACHI gives EPDM 15 to 25 years, TPO 7 to 20 years, modified bitumen 20 years and built-up roofing 30 years.

The EPDM Roofing Association has announced an expected service life of 38 years for EPDM membranes that are properly designed, installed and maintained. It based that on field studies, lab testing and a 2025 survey of 569 roofing professionals, who reported expected lives from about 25 years to more than 40, depending on the thickness of the membrane and how it is attached. For TPO, InterNACHI’s chart is the only service-life figure among this guide’s sources.

Some low-slope roofs are torch-down roofs, where the roofer heats modified bitumen with a flame to bond it. Conshohocken’s addendum requires a separate operational permit for hot work, with a $75 fee, and a call to the borough Fire Marshal’s office before the work starts.

Warranties and service life

A manufacturer’s warranty term is a different number from a service-life estimate. Mark S. Graham, NRCA’s associate executive director of technical services, wrote that long residential warranties do not necessarily ensure a roof performs, because they often limit the manufacturer’s liability and most require the roof to be properly maintained. NRCA recommends inspecting a roof at least twice a year, and this site’s roof inspection checklist follows that advice.

Attic ventilation affects the warranty as well. Conshohocken’s re-roofing addendum asks whether the owner was told that inadequate ventilation may void the manufacturer’s warranty, and it sets the borough’s minimum ventilation ratio.

Matching the roof to what goes on it

InterNACHI rates solar panels at 20 to 30 years, about the same as asphalt shingles. If panels go on a roof with less life left than the panels, they will have to come off when the roof is replaced. The guide to rooftop solar with PECO covers the rules for connecting a system, and the weather guide covers the freeze-thaw days, rain, wind and hail that wear a roof here.