Causes of Wear or Leaks in Asphalt Shingle Roofs

...

Effects of Climate On Asphalt Shingles:

Carl Cash asserts that the mean durability of "20-year" shingles is less than 20 years everywhere in the U.S. except Alaska.

Variations in climate permit calculation of a wear-acceleration factor for various cities. Higher thermal load (hotter climates) means shorter life.

Yuma, AZ mean durability was calculated at 12.6 years, for example, and Ft. Meyer FL 14.1 years while Chicago at 19.7 years and Erie, PA at 20.7 years showed longer life in cooler climates.

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

• Also see key citations found at the end of this article atReferences or Citations
• Bailey, David M. Roofer: Steep Roofing Inventory Procedures and Inspection and Distress Manual for Asphalt Shingle Roofs. No. CERL-TR-99/100. CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL, 1999.
• Dunlop, Carson. Essentials of Home Inspection: Home Reference Book. Dearborn Real Estate, 2003.
• Dunlop, Carson. Principles of Home Inspection: Roofing. Vol. 5. Dearborn Real Estate, 2003.
• Dunlop, Carson. Principles of Home Inspection: Systems & standards. Review questions & answers. Vol. 15. Dearborn Trade Publishing, 2003.
• Krivit, Dan, "Shingles, Recycling Tear-Off Asphalt. "Best Practices Guide."" [PDF] Construction Materials 21 (2007), Dan Krivit & Assoc., St. Paul MN, DKrivit@bitstream.net, Tel: 651-489-4990, Construction Materials Recycling Association (CMRA), Email: info@cdrecycling.org, Tel: 630-585-7530, retrieved 8/8/2014, original source: https://www.shinglerecycling.org/sites/www.shinglerecycling.org/files/shingle_PDF/ShingleBPG%2010-07.pdf
• Fry, Lloyd A. "Method of treating asphalt shingles and composition therefor." U.S. Patent 2,000,226, issued May 7, 1935.
• Marshall, Timothy P., Richard F. Herzog, and Scott J. Morrison. "Hail Damage to Asphalt Roof Shingles." In 22nd Conference on Severe Local Storms. 2004.
• Turos, Mugurel I., Augusto Cannone Falchetto, Gabriele Tebaldi, and Mihai O. Marasteanu. "The Flexural Strength of Asphalt Mixtures Using the Bending Beam Rheometer." In 7th RILEM International Conference on Cracking in Pavements, pp. 11-20. Springer Netherlands, 2012.
• Taunton Press. Roofing. Taunton Press, 1997.
• Verwimp, Jo, Marleen Rombouts, Eric Geerinckx, and Filip Motmans. "Applications of laser cladded WC-based wear resistant coatings." Physics procedia 12 (2011): 330-337.
• Weiss, John Morris. "Asphalt Shingles." Industrial & Engineering Chemistry 23, no. 2 (1931): 168-170.

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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

...

Continue reading at ASPHALT SHINGLE FAILURE TYPES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• ASPHALT ROOF SHINGLES - home
• ASPHALT SHINGLE INSTALLATION
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• ASPHALT SHINGLE LIFE / WEAR FACTORS
• ASPHALT SHINGLES on LOW SLOPE ROOFS
• ATTIC MOLD ROOF TEAROFF
• ROOF LEAK DIAGNOSIS & REPAIR
• ROOFING MATERIALS, AGE, TYPES
• ROOFING MATERIAL AGE vs BUILDING AGE
• ROOF SHINGLE STORAGE - improper storage can damage shingles & reduce their on-roof life
• SHINGLE EXPOSURE AMOUNT
• WARRANTIES for ROOF SHINGLES
• WIND DAMAGE to ROOFS

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Citations & References

In addition to any citations in the article above, a full list is available on request.