How To Look At A House
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What's the average lifespan of a roof?
Thursday, June 28, 2018
The life expectancy of a roof varies between different roof materials. Here’s the averages, and click on any roof type in the list for more info about it:
Asbestos Cement Shingle - 40 to 60 years, average 50
Asphalt Shingles, 3-tab - 16 to 22 years, average 20
Asphalt Shingles, Architectural/Dimensional - 24 to 30 years, average 27
Built-up - 17 to 25 years, average 20
Built-up and Gravel - 20 to 30 years, average 25
Concrete/Clay Tile - 40 to 60 years, average 50
Corrugated Asphalt Panels - 9 to 13 years, average 11
EPDM (Ethylene Propylene Dyene Monomer) - 20 to 30 years, average 23
Metal (Galvalume) - 30 to 50 years, average 40
Modified Bitumen - 10 to 17 years, average 15
Patio Cover - 20 to 30 years, average 25
PVC - 20 to 30 years, average 25
SPF (Spray Polyurethane Foam) - 20 to 50 years, average 30
TPO (Thermoplastic PolyOlefin) - 20 - 30 years, average 23
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, thicker shingles last longer.
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.
Also, see our blog posts Should I buy a house that needs a new roof? and How can I tell if the house needs a new roof?
Go to our blog post What is the average lifespan of the parts of a house? for rating of other house components. To understand the basis, potential use, and limitations of lifespan ratings, see our blog post ”How accurate are the average life expectancy ratings of home components? Are they actually useful?”
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To learn more about roofs and attics, see these other blog posts:
• Why is my roof sheathing sagging between the trusses?
• Are H-clips required by the building code for roof sheathing?
• What would cause a home inspector and roofing contractor to disagree on the remaining life left in a roof?
• Why is granule loss a problem for an asphalt shingle roof?
• What are the mistakes to avoid when doing attic improvements?
• What causes roof shingles to curl up at corners?
• What causes shingles to buckle along a line on the roof?
• What causes leaks at a fake roof dormer?
• What causes a sagging roof ridge line?
• What causes bubble-like blisters in a built-up and gravel roof?
• Why does it cost so much more to replace a steep roof than a low slope roof?
• What is "ponding" on a flat roof?
• Is an attic required to have a light by the building code?
• How can I inspect my roof for hurricane damage?
• Why is premature curl of roof shingles a problem?
• How can I tell if a roof has more than one layer of shingles?
• What are the common problems with attic insulation?
• What is the life expectancy of an asbestos cement shingle roof?
• Why is it a mistake to replace a roof and not replace its flashings?
• Why is there no attic access hatch in the house?
• What is the building code requirement for an attic access hatch, scuttle, or door?
• Does a roof with multiple layers of shingles last longer?
• What can I do to prevent roof leaks?
• Are roof trusses better than roof rafters (stick framing)?
• Why is a popped nail in a shingle roof a problem? How do I fix it?
• What are the most common problems with wood roof trusses?
• What causes a lump or dip in the roof?
• If my roof is not leaking, why does it need to be replaced?
• Is a ridge board/beam required for a roof framed with rafters?
• Does it cost more to roof a hip roof than a gable roof?
• How can I be sure my roofing contractor got a permit?
• How many layers of roofing are allowed on a home?
• What are the dark lines running parallel to shingles on my roof?
• Can metal roofing be used on a low slope/pitch roof?
• How can I make my roof last longer?
• What are the warning signs of a dangerous attic pull-down ladder?
• How can I find out the age of a roof?
• Should I buy a house with an old roof?
• What are those metal boxes on the roof?
• What does "lack of tab adhesion" in an asphalt shingle roof mean?
• Why do roof edges start leaking?
• Why do my dormer windows leak?
• Do home inspectors go on the roof? Do they get in the attic?
• Should I put gutters on the house?
• What's the difference between a roof inspection and a roofing estimate?
• How much of a roof truss can I cut out to make a storage platform in the attic?
• What's the difference between an "architectural" and a regular shingle roof?
• I'm buying a '50s modern house with a "gravel" roof. Is the roof going to be a problem?
• What does a home inspector look for when examining a roof?
• Do stains on the ceiling mean the roof is leaking?
• Why does my homeowner's insurance want a roof inspection?
• What are the hazards to avoid when going into an attic?
• What is a roof certification letter/report?
Visit our ROOF AND ATTIC and LIFE EXPECTANCY pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.
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