The life expectancy of a roof varies between different roof materials. Here’s the averages:
Asphalt Shingles, 3-tab - 15 to 18 years
Asphalt Shingles, Architectural - 24 to 30 years
Galvalume (metal) - 30 to 45 years
Concrete Tile - 35 to 50 years
Built-Up or Modified Bitumen - 10 to 16 years
EPDM (rubber) - 10 to 16 years
But average lifespan estimates are based on “average” conditions. Many factors contribute to a longer or shorter life of the roof; so a particular roof’s life can vary—sometimes significantly—from the average. Here’s a list of conditions that affect roof longevity:
Color of roof - A dark roof absorbs more heat, which shortens the lifespan.
Angle of roof slope - Higher pitch roofs tend to last longer.
Orientation of roof surface - A roof slope facing south will get more sunlight, and have a shorter life.
Multiple-layer roof - A roof installed over an existing roof will have a shorter life.
Quality of roof material - “Economy” roof materials have a shorter life.
Installation - Sloppy or improper installation shortens roof life.
Attic ventilation - An unventilated or poorly ventilated attic reduces roof lifespan.
Trees near roof - Tree branches rubbing on a roof or the acidity from the accumulation of leaf debris on a roof shortens its life.
Harsh climate - Severe weather, both harsh winters and hot summers, along with big temperature swings within a 24-hour period, also shorten lifespan because of the expansion and contraction of roof materials.