Asphalt Shingle Cupping & Clawing, Signs of Roof Shingle Wear
CUPPING ASPHALT SHINGLES - CONTENTS: Asphalt roof shingle cupping description, definition, diagnostic photographs. Types & photographs of cupped organic felt asphalt roof shingle defects & failures. What questions to ask your roofing manufacturer if you believe you have a shingle warranty claim
POST a QUESTION or READ FAQs about shingle cupping: causes, remedy, types of roofs where cupping asphalt shingles are most often found, impact on remaining roof life
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Cupping asphalt shingles: this article series describes cupped asphalt roofing shingles and
how to identify & explain the most-common asphalt roof shingle failures.
These cupping shingle defects occur on both organic-mat and fiberglass-mat
asphalt roof shingles, but are more common on organic mat asphalt shingle roofs.
We describe the difference between shingle cupping & shingle curling - which can be important in diagnosing the cause of early roof wear or damage. And we warn against walking on cupped shingle roofs. Readers are also invited contribute roof failure information to the web author for research purposes.
web author for research purposes.
Cupping asphalt roof shingles, particularly on organic or felt-based asphalt shingles, are a normal wear pattern that shows
up with shingle age.
Cupped asphalt shingles are show in our page top photo and in others on this page. In our photo (left) the top arrow in the photo at left points to the left side of a "cupped" area of this roof shingle. The shingle edges
are also curled in these photos, which is part of this wear pattern.
This "normal" cupping or curling pattern will display shingles which are concave in their center,
with the corners and possibly the three exposed shingle tab edges curled such that the very edge of the shingle curls downwards.
Definition of Asphalt Shingle Clawing
"Clawing" is also used to describe the appearance of asphalt roof shingle corners that curl down and under (photos above and below). Marshall et als (1999) observed:
Cupping and clawing results from asphalt shrinkage on the top and bottom surfaces of the shingles, respectively. The corners and edges of the shingles are prone to curling or cupping as the mat shrinks. Crazing of the shingle surfaces also results from asphalt shrinkage. Eventually, chunks of granules flake away from the mat leaving the asphalt coated mat exposed to the weather. - Marshall et als (1999)
Common Asphalt Shingle Wear Indicators are often combined on a single roof
Shingles in this condition are fragile and nearing end of life. In this condition, if someone walks on cupped shingles the raised
cupped sections will break and can lead to early failure and leaks.
Our photo (left) shows that on the right-hand roof, virtually all of the shingles are cupped (red arrows & lines) and the shingles are also fish-mouthed. The staggering of fish mouthing on the roof is consistent with the location of shingle butt joints in successive courses.
Asphalt roof shingles as they wear either normally or in some cases at an accelerated (early failure) rate, often show one of the following wear signs, but as our photo at left illustrates (both cupping & curling) shingles can show any or all of these wear signs in combination as well.
Cracking shingles - fine or wide cracks through the shingle surface and into or through the shingle body
Cupping / clawing shingles - the roof shingles develop a concave center (discussed here)
Curling shingles - raised shingle edges which curl downwards)
shingles - raised edge of a shingle tab at its center with little curling , most often over the butt-joint of two shingles in the course below
Granule loss from shingle surfaces - the mineral granules are washing off of the shingle surface, exposing bald shingle substrate below. Granule loss may also occur from foot traffic, mechanical damage, or hail damage.
Each of these asphalt roof shingle conditions is different in appearance and while all of them may indicate worn, old, or
fragile roof coverings, their causes and prevention vary. In some of the photos of cupped roof shingles on this page, "fishmouthing" is also
visible (see photo at page top). It is common for multiple wear signs to be present at once.
Cupped roof shingles are fragile: You should avoid walking on cupped-shingle roofs, particularly in cold weather (shingles are more likely to break).
As you can see in our photo (left) the raised fishmouth section of the cupped shingles is already cracking on its own. Stepping on this raised point (blue arrow) or on the raised area of the cupped shingle (red arrow) is likely to break it, converting a worn-out roof into one that is actively leaking.
If we absolutely have to walk on such a roof, we would tiptoe carefully, avoiding stepping on the raised or cupped shingle
sections, or if doing repairs, we would prop a ladder up off of the roof surface and work from that scaffold as is sometimes done
with slate or other fragile roof surface repairs.
Walking on a cupped shingle roof can cause irreparable damage: Take this warning seriously: an old cupped asphalt shingle roof may not yet be
leaking and could last several more years depending on its condition.
But we have seen cupped asphalt shingle roofs that had
been destroyed by the "inspector" who walked all over the roof, breaking shingles everywhere he stepped, leaving a trail of
damage and leading to the need for an immediate roof replacement. The roof would have needed replacement soon before the "inspection."
After the "inspection" the roof needed immediate replacement. we could actually see the "footprints of destruction" across
the roof surface.
Research Citations for Asphalt Shingle Cupping & Clawing
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.
Cash, CARL G. "Asphalt roofing shingles." In Proceedings of the 11th Conference on Roofing Technology, National Roofing Contractors Association, Rosemont, Illinois, pp. 1-9. 1995.
Cullen, WILLIAM C. "Research and performance experience of asphalt Shingles." In 10th Conference on Roofing Technology, vol. 7. 1993.
Cullen, William C. "The Evolution of Aspahlt Shingles: Survival of the Fittest?." Professional Roofing (1992).
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.
Greenfeld, S.H., 1969: Hail resistance of roofing
products, Building Science Series #23, National
Bureau of Standards, 9 pp.
Koontz, J.D., 1991: The effects of hail on residential
roofing products, Proc. of the Third International
Symposium on Roofing Technology, NRCA/NIST,
Ilnyckyj, Peter. "Shingles." U.S. Patent 5,442,888, issued August 22, 1995.
Koontz, Jim D. "The effects of hail on residential roofing products." In Proceedings of the Third International Symposium on Roofing Technology,” NRCA/NIST. 1991.
Lockinger, Paul. Understanding a Home Inspection. Florian Valentine Publishing, 2009.
Marshall, Timothy P., Richard F. Herzog, and Scott J. Morrison. "Hail Damage to Asphalt Roof Shingles." In 22nd Conference on Severe Local Storms. 2004.
McNulty, Raymond A. "[Asphalt Roof Shingle] COMPOSITION, PERFORMANCE, FUNCTION, AND STANDARDS." Interface (2000).
Morrison, S.J., 1999: Long-Term Effects of Hail on
Asphalt Composition Shingles Proc. of the North
American Conf. on Roofing Technology, Toronto,
Noone, MICHAEL J., and W. KENT Blanchard. "Asphalt Shingles–A Century of Success and Improvement." In Proceedings of the 10th Conference on Roofing Technology, pp. 23-33. 1993.
Ribble, R. E. I. D., R. I. C. K. Olson, D. Summers, and J. O. N. A. T. H. A. N. Goodman. "From generation to generation: issues and problems facing the steep-slope roofing industry." In Proc. of the 10th Conf. on Roofing Technology, vol. 1, no. 5. 1993.
FAQs below discusses field reports of problems & solutions for this topic
Frequently Asked Questions (FAQs) about cupping asphalt roof shingles
Question: why are shingles on my new roof cupping ?
Why is my new Roof cupping and it is only 2 weeks old? Yes Two weeks? - Joyce 11/28/11
Cupping of brand new roof shingles would be unusual. It might occur if shingles were installed over a wet roof deck or over an old layer of cupped, curled, or wet roof shingles.
Use the CONTACT link found at page top, left, or bottom to send us some sharp photos of the roof including some closeups and photos from a low angle that shows the cupping and we may be able to comment further.
Question: My 25-year warrant asphalt shingles are cupping after 13 years
I have a situation where my asphalt shingles have a 25 year material warranty and were installed 13 years ago. A large portion of the shingles are now cupping. The roof is a very simple hip roof with a single gable and one valley. Why are the shingles failing at approximately half of their life? Should the shingle manufacturer be held liable for the early product failure? Will they actually honor this material warranty? - Scott S. 3/12/12
Scott, shingle warranty claims are honored by manufacturers based in part on the manufacturer's assessment of the nature of the problem and their determination of whether the problem is due to faulty product or due to other problems such as a faulty installation or a structural or roof venting problem. You will want to contact the manufacturer and ask them to take a look at the roof, and
First, agree that there is a problem that affects the anticipated roof life
Second, name and define the problem
Third: state an opinion about its cause
Third: provided they agree that the problem is not just cosmetic, indicate if the roof warranty applies
Fourth: give you details of what warranty coverage is actually provided. Typically warranties cover a pro-rated portion of product cost and often labor is excluded.
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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Green Roof Plants: A Resource and Planting Guide, Edmund C. Snodgrass, Lucie L. Snodgrass, Timber Press, Incorporated, 2006, ISBN-10: 0881927872, ISBN-13: 978-0881927870. The text covers moisture needs, heat tolerance, hardiness, bloom color, foliage characteristics, and height of 350 species and cultivars.
Green Roof Construction and Maintenance, Kelley Luckett, McGraw-Hill Professional, 2009, ISBN-10: 007160880X, ISBN-13: 978-0071608800, quoting: Key questions to ask at each stage of the green building process Tested tips and techniques for successful structural design
Construction methods for new and existing buildings
Information on insulation, drainage, detailing, irrigation, and plant selection
Details on optimal soil formulation
Illustrations featuring various stages of construction
Best practices for green roof maintenance
A survey of environmental benefits, including evapo-transpiration, storm-water management, habitat restoration, and improvement of air quality
Tips on the LEED design and certification process
Considerations for assessing return on investment
Color photographs of successfully installed green roofs
Useful checklists, tables, and charts
Roofing The Right Way, Steven Bolt, McGraw-Hill Professional; 3rd Ed (1996), ISBN-10: 0070066507, ISBN-13: 978-0070066502
Slate Roofs, National Slate Association, 1926, reprinted 1977
by Vermont Structural Slate Co., Inc., Fair Haven, VT 05743, 802-265-4933/34. (We recommend this book if you can find it. It
has gone in and out of print on occasion.)
Roof Tiling & Slating, a Practical Guide, Kevin Taylor, Crowood Press (2008), ISBN 978-1847970237, If you have never fixed a roof tile or slate before but have wondered how to go about repairing or replacing them, then this is the book for you. Many of the technical books about roof tiling and slating are rather vague and conveniently ignore some of the trickier problems and how they can be resolved. In Roof Tiling and Slating, the author rejects this cautious approach. Kevin Taylor uses both his extensive knowledge of the trade and his ability to explain the subject in easily understandable terms, to demonstrate how to carry out the work safely to a high standard, using tried and tested methods.
This clay roof tile guide considers the various types of tiles, slates, and roofing materials on the market as well as their uses, how to estimate the required quantities, and where to buy them. It also discusses how to check and assess a roof and how to identify and rectify problems; describes how to efficiently "set out" roofs from small, simple jobs to larger and more complicated projects, thus making the work quicker, simpler, and neater; examines the correct and the incorrect ways of installing background materials such as underlay, battens, and valley liners; explains how to install interlocking tiles, plain tiles, and artificial and natural slates; covers both modern and traditional methods and skills, including cutting materials by hand without the assistance of power tools; and provides invaluable guidance on repairs and maintenance issues, and highlights common mistakes and how they can be avoided.
The author, Kevin Taylor, works for the National Federation of Roofing Contractors as a technical manager presenting technical advice and providing education and training for young roofers.
The Slate Roof Bible, Joseph Jenkins, www.jenkinsslate.com,
143 Forest Lane, PO Box 607, Grove City, PA 16127 - 866-641-7141 (We recommend this book).