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Typical wear due to age on an organic base asphalt shingle roof. Causes of Wear or Leaks in Asphalt Shingle Roofs

This document describes most of the factors which determine the life expectancy of an asphalt shingle roof - "roofing shingle wear factors". These wear factors affect most asphalt roof shingle types, whether organic felt based or fiberglass fabric based, and whether the shingle type is "cutout" or three-tab, strip-type, or a laminate-type roof shingle.

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SHINGLE LIFE / WEAR FACTORS for Asphalt Shingle Roofing Products

Fishmouthed roof shingle fail(C) Daniel FriedmanThis article is part of our series on inspecting, diagnosing, installing and repairing Asphalt Roof Shingles which tells readers how to identify & explain the most-common asphalt roof shingle failures.

[Click to enlarge any photo or image]

By listing common causes of asphalt roof shingle failures and how to recognize them, building owners and roofing contractors may also be able to reduce the occurrence of asphalt roof shingle storage, handling, and installation errors that affect roof life. Readers are also invited contribute roof failure information to the web author for research purposes.

While the historical cost-performance of this product has been good in most cases, durability issues and wear-out or material failures occur earlier than expected in some situations. The expected life of a roof covering depends on many variables including:

Improperly stored asphalt shingle absorbs water (C) Daniel Friedman

Building factors affecting asphalt shingle roof life:

Cost Effectiveness of Asphalt Shingles:

Other roofing materials also are affected by thermal loading. Cash calculates that the life cycle cost of steep-slope roofing shows that asphalt shingles still provide the most economical performance for the home owner! ("Asphalt Shingle Performance," - - Carl Cash.)

Given these variables, it is not likely that a "20-year" shingle will expire exactly twenty years after it is installed. When a roof lasts longer than its promised life no one complains. If a roof needs replacement substantially sooner than its anticipated life, consumers are understandably concerned.

Asphalt Roof Shingle Wear Factors Research Citations

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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-12-05 4 - by (mod) -

at the lower roof pitches where the quantity of water is greatest and in the cutouts between the shingle tabs

On 2020-12-05 by Curtie

Three tap asphalt roofs are most likely to wear at what location first.

On 2017-07-06 by Barbara Beardsley Brandt

pine branches on the 1940s barn/garage roof. Neighbor's tree. Problem. lots of moss on shingles and seems related to branches. Afraid to use baking soda in he event rmoving moss would cause deterioration and leaks. Or perhaps some way to put composite panels over the existing roof with roofing company to avoid this.

Cost for a roof quoted at $2000 plus with removing shingles for new. Insurance pays for the new roof but deductible determines when I can undertake the new roof or fixed roof.

On 2016-07-05 - by (mod) -

Anon I can't imagine; Start at the roof: what is it made-of, what coatings, flashings, mastics, cements were applied where?

On 2016-07-05 by Anonymous

Why is my new roof leaking brown sticky slime all around my patio driveway etc

On 2016-04-20 by Anonymous

Jahn,

I would not rely on paint to stop roof leaks. Look for the actual point of water entry, have the roof surface inspected carefully from above for nailing errors, damaged shingles, improper flashing, missing flashing at a ridge vent etc.

On 2016-04-20 by jahn

Can asphalt shingle roof be painted in water based acrylic.

What is the best way to stop water leaking in the ridge areas

On 2013-02-10 by Petro

Thanks for the info, it is useful in making decision to buy.

On 2013-01-25 by Anonymous

I see some sort of shiny stuff, or lines, at the left and right edges of numerous shingles on the upper south side of our house roof. Facing southerly, steep roof. So...are they shrinking (put in about 1996) so an adhesive is showing, or ?? Houston, Texas area.

On 2012-04-05 by Cheryle

I just purchased a 61-yr old Cape style home in Randolph, MA. The roof is multi shingled--2 layers of asphalt shingles. The top shingles are less than 8 yrs old. My HO insurance was just cancelled because shingles are lifting. Home inspector indicates lifting is caused by lack of appropriate venting.

I am having 2 12" mushroom vents installed. The question my insurance co is asking is, with proper venting will the lifting shingles settle down?

On 2011-11-02 by Anonymous

Thank you so much-I'll keep you posted

On 2011-11-02 - by (mod) -

Anon:

ALSO you are welcome to send me some sharp up close photos as well as general photos of the field of the roof - for comment. Use the CONTACT link found on our pages.

On 2011-11-02 - by (mod) -

Anon:

Certainly it's possible for foot traffic as well as falling masonry debris to damage a roof surface. Possible damage that can be spotted by careful visual inspection includes at least:

Mineral granule loss that reduces the remaining roof life

Punctures in the roof covering caused by falling debris

Disturbed flashing that leaves lifts, bends, tears, cuts that may leak

Even torn or broken shingles if this is an a asphalt shingle roof.

To demonstrate that such damage has occurred you'll need a competent on-roof inspection by a neutral professional who will photograph and document his or her findings. Key in placing responsibility would be being able to show that the damage observed is

Recent

Occurs only in the area where work took place

and to be unimpeachible you'd need to claim if not actually demonstrate that no one else had been on the roof in the area of damage and that the damage was not pre-existing.

I'd prefer that the roof be inspected before it is rinsed or treated in any way since rinsing off the roof may remove useful evidence such as an area of loose, disturbed granules not found elsewhere, and worse, if the roof was damaged it may leak.

If the wear from foot traffic is quite modest and there are no actual shingle areas (assuming we're talking about mineral granule coated shingles or roll roofing or a similar product) that show the shingle substrate, that is, if there is remaining at least some mineral granule coating all over the shingles, then the impact on remaining roof life may not be measurable.

Keep us posted on how things are resolved - what you learn will help other readers.

On 2011-11-02 by Anonymous

I need some answers from an unbiased but knowledgeable source. Workers came to my house to remove a brick chimney but believing no one was home, got on the roof to do this job and in addition to standing on the roof they allowed the broken protions of chimney (6-10 brick sheets) to fall on the roof. I stopped their work but now their company head says the roof isn't damaged just needs to be rinsed.

I think that brick and the two workers on the roof had to have caused damage, even if it isn't obvious. What is likely, damaged or not? If damaged, how do I prove it. Thanks in advance!

On 2011-06-16 - by (mod) -

Sticky asphalt roof shingles:
Yes indeed, if you leave asphalt shingles on a roof for long in the hot sun there is a real risk that they will stick together. You can reduce the risk by storing them in shade or covering them with a light colored tarp.

On 2011-06-14 by Anonymous

if i leave asphalt shingles on roof will they stick together


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