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This article series on asphalt roofing explains how to recognize and diagnose the cause of the most-common asphalt roof shingle failures and how to obtain asphalt roofing shingle failure claims assistance. Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman. Guide to Asphalt RoofingCommon asphalt shingle failure factors include improper storage and handling of the asphalt shingles before installation, improper nailing, improper flashing (which pertains to any roofing material), and defective asphalt shingle product material leading to thermal splitting, cracking, blistering, staining, and in some cases curling or cupping shingles. Storm damage from wind and hail occur and need to be distinguished from defective asphalt shingle product or asphalt shingle installation errors. 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. Shingle failures: Readers are also invited contribute roof failure information to the web author for research purposes. web author for research purposes.
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Please see CRACKS in FIBERGLASS SHINGLES for our full discussion of this type of asphalt shingle failure, its cause, how to recognize it, and what to do about it.
What does it look like?
We have observed a variety of torn or split shingles:
Horizontal or vertical tears across multiple 3-tab shingles
Horizontal, vertical, and diagonal tears across multiple strip-type shingles
Horizontal, vertical, diagonal, and corner tears across multiple laminate-type shingles
Both horizontal and diagonal or vertical tearing may occur in the same roof
Probable Cause of Splits in Asphalt Shingles
- It's possible that shingles made by some manufacturers do not meet the ASTM Standards for tear resistance.
- Even where shingles meet the Standards, it's possible that the standards themselves were defective.
- In any case, Fiberglass mat may lack adequate tear resistance
- Self-sealing tabs on shingle backs may glue shingles together with too much strength, causing the roof covering to form a single large membrane which cannot accommodate large temperature changes
- Reduced total amount of asphalt in thin fiberglass mats might become brittle after exposure to heat and sunlight
- Temperature swings probably contribute to the onset and extent of tearing, and we'd expect worse tearing where temperature swings are more extreme such as in Northern climates.
- Nailing or placement pattern of shingles: "laddering" vs. "staggered." On laminate and strip type shingles we have inspected roofs on which damage is found occurring at the corners of shingles rather than in the middle of the shingle material. It appears that as temperatures dropped and the glued-together-roof-membrane cools and contracts, the natural point at which movement occurs is where shingles are end-butted together. When the pattern of end-butts is laddered rather than staggered up the roof we have found corners tearing off of shingles following the laddering pattern exactly. (Laddering is not a recommended installation pattern according to NRCA and ARMA publications nor according to instructions from some manufacturers.) Laddering alone cannot be blamed for this failure however, as we have seen similar shingle tearing following a staggered end-butt pattern up other roofs. However laddering may indeed create a more localized natural point of separation on a roof, causing most of the movement to occur in a smaller area when the roof material contracts with cooling.
ORGANIC FELT SHINGLES - Organic-mat-based Asphalt Roof Shingle Wear & Failures
Please see ORGANIC FELT SHINGLE DEFECTS for our full discussion of this type of asphalt shingle failure, its cause, how to recognize it, and what to do about it.
Granule LossBuckling
Cupping
CurlingHeadlap coating wear out exposed at shingle cutouts
Blistering
Holes and nail-pops in Asphalt Shingles
Algae, Fungus, Staining in Asphalt Shingles
Workmanship Failures in Asphalt Roofing
Workmanship: Fasteners/Nailing Problems lead to holes or wind blow-off
Workmanship: Installation Pattern Problems:Laddering (Photo: Carl Gerosa, New Rochelle, NY)
Workmanship: Flashing and underlayment problems
Workmanship: Improper materials/roof-slope problems
Asphalt Shingle Blisters
Blisters in shingles wear off from weather or foot traffic, becoming pits, causing moisture absorption and in cold
climates increase in wear rate from frost. Blisters are a manufacturing defect which are sometimes mistaken for hail damage.
Asphalt Shingle Splices
Splice Shingles used to keep material moving during the manufacturing process should be discarded but they almost
always end up installed on the roof. Spliced asphalt shingles are a factory defect - and were not supposed to
have been installed. The occurrence of spliced shingles on an asphalt shingle roof will be rare. We recommend
simply replacing the damaged area with a new shingle. Temporary repair can be made by sliding a piece of
metal flashing under the damaged area.
Aesthetic or Cosmetic Roofing Issues
Some consumers have concerns with how their shingles look on the roof as much as with how long the roof will last. Roofing manufacturers offer a wide variety of products which give different "looks" and shadings. It's possible that in addition to site and installation conditions, variations in manufacturing process (granule adhesion, bleed-through) can affect how the roof looks from the ground.
We've also investigated client concerns with shadows appearing in early morning or late afternoon which show variations in the roof surface. (Some shadows which are only of cosmetic nature may be caused by slight buckling or unevenness in the roof decking and may not indicate a structural or durability concern.)
If you have particular concerns about roof appearance ask your roofer if s/he can direct you to a house where the product which interests you is already installed. Remember that site differences (orientation to sun, shade trees, height above ground, roof pitch, and probably other factors) may make shingles look a bit different on your house.
Please see BLACK STAINS on SHINGLES for our full discussion of the types and causes of stains on asphalt roof shingles.
Black Stains on Asphalt Roof Shingles
There are several common sources of roof shingle stains, each of which may have its own cause and treatment.
Bleed-Through or Extractive Bleeding Stains on Asphalt Shingles
Extractive bleeding or "bleed through" leaving black streaks running down an asphalt shingle roof is an indication of a defective roofing product. The chemistry of the shingle is permitting black pigment from the asphalt to leach to the shingle surface and run down the roof. Typically bleed-through on asphalt shingles appears as black streaks running down shingles. You'll see black streaks of varying length.
Because of variations during the shingle manufacturing process, and possibly because of variations in site conditions (sun, shading, slope, moisture), different roof areas or slopes on the same building may display different amounts of black staining. (This term is commonly used with wood shingles.)
Remedies for bleed through staining on asphalt shingles: we wouldn't do much to a roof with this staining since we worry that power washing or chemical treatments may reduce the remaining roof life. At re-roof time I'd buy a better-grade replacement shingle.
Black Algae Staining on Asphalt Shingles
Misnamed as "mildew" or "fungus" by some writers, algae staining on asphalt shingles usually in shaded areas or on the more-shaded roof slopes- characterized by black staining fairly uniform over shingles, but appearing specifically in areas of the roof shaded by nearby trees.
Black algae stains on asphalt shingles tend to be fairly uniform over the stained area, not streaky as with bleed-through stained shingles.
Black algae staining on an asphalt shingle roof is actually dead organic debris from an alga, (possibly Gloeocapsa magma).
Remedies for black algae staining on shingles: Black stains on asphalt shingles caused by algae is avoided by some of the new roof shingle products which include chemicals to retard algal growth. Cutting back overhanging tree branches for more sun can also help reduce this problem. Zinc or copper strips tacked along the ridge will produce (in rain) metal salts which will kill algae as they wash down the roof.
Some folks recommend power washing to get reduce the staining - we would be concerned that the power washing process might damage the shingles and significantly reduce the remaining shingle life.
Debris Staining on Asphalt Shingle Roofs
Debris staining on roofs produces fairly uniform black or brown staining in areas where due to low-slope or presence of overhanging trees, organic debris collects on the roof slope. Decaying debris may encourage fungal or algal growth (cited above).
Lichens or even thick moss may also grow on such roof areas. Debris, lichens, or moss on a roof will shorten its life by holding water on the roof surface, preventing drying, and (in cold climates) adding wear and tear on the roof surface by freeze-thaw cycling.
Remedies for black or brown or gray debris staining on asphalt shingles: As cited above, cleaning off debris (gentle sweeping or washing, watch out for damaging the roof during cleaning), or cutting unnecessary overhanging tree branches may help.
Black Stains on Roof Shingles Around Chimneys
Soot from fireplace flues washing down onto the roof - characterized by staining appearing below and in line with the chimney
Similarly, soot from oil-fired heating flues washing down onto the roof, characterized by the same pattern of staining around and below the chimney; also probably an indicator of an operating problem with the heating system.
Gas Flue Safety Warning: If this same sooting appears on and around a gas-fired appliance flue, there is a very unsafe condition present and risk of fatal carbon monoxide production inside the building. Immediate action is be needed.
Roofing Warranties - Valuable or Worthless?
In certain instances specific roofing products have shown common early failure, failing in a characteristic pattern which is easily identified (such as the thermal splitting defect. Some manufacturers offer limited warranty coverage of their product. Many roofers also guarantee their work to be free from leaks, but usually for a time period substantially shorter than the manufacturer's rated life of the roof material.
Please see ROOFING WARRANTIES for our full discussion of roofing shingle warranties, class actions and settlements, how to report shingle failures, and a shingle failure report form.
In cases which we've handled recently involving thermal splitting or tearing of fiberglass-based asphalt shingles, some manufacturers (such as GAF) offer a limited product warranty. Following a fairly involved claims procedure requiring documentation, photographs, and a sample of damaged material the manufacturer may elect to warrant the roofing material on a pro-rated basis depending on the age of the roof and its warranted life. Sometimes the manufacturer's warranty covers only material cost, not installation cost (labor, demolition, removal of old materials) unless the roofing contractor chooses to extend such coverage.
The cost of roofing material is not the main ingredient in roofing cost. Labor and possibly disposal of old roofing material are significant costs. Out of concern for future roof life, some roofers are reluctant to install new roofing atop failed material even where additional layers of roofing are permitted by local codes.
Some homeowners are reluctant to install as new roofing the same product which failed early in the first place. Manufacturers might have changed the formulation of the product to improve durability, but they are understandably reluctant to say so, out of concern for increasing product liability. Without assurance from the manufacturer that a product which failed early has been modified to correct the problem, we advise our clients to consider using alternative products with design and performance expectations having a better track record.
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Roofing Manufacturer Contact Information - Please see ROOFING WARRANTIES for our full discussion of roofing shingle warranties, class actions and settlements, how to report shingle failures, and a shingle failure report form.
- Atlas Roofing, 802 Highway 19 N, Ste. 190, Meridian MS 39307 601-484-8900
- Bird Inc., (obs. address: 1077 Pleasant St., Norwood MA 02062 617-5551-0656) is - an affiliate of CertainTeed Corporation - so try contacting CertainTeed: P.O. Box 860, 750 East Swedesford Road, Valley Forge, PA 19482 USA Phone: (610) 341-7000 Fax: (610) 341-7113 E-mail: corporate@certainteed.com
- Brookline School District v. Bird, Inc.
- BPCO, 9510 St. Patrick, LaSalle, P! H*R 1R9 Canada 514-364-0161
- Celotex Corp., 4010 Boy Scout Blvd., Tampa FL 33607-5750 813-873-1700
- Certainteed, 750 E. Swedesford Rd., BOx 860, Valley Forge PA 19482 610-341-7000
- Elk Corp., 14643 Dallas Pkwy, Ste 1000, Dallas TX 75240-8871 214-851-0400
- GAF, 1361 Alps Rd., Wayne NJ 07470 201-628-3000 - Technical Services & Guarantee Status Office 1-800-ROOF-411
GAF class action settlement - call 800-414-4370 for more information or see the GAF Class Action Lawsuit Settlement Website - Globe Building Mtls, 2230 Indianapolis Blvd, Whiting IN 46394 219-473-4500
- IKO Chicago, Inc., 6600 South Central Ave., Bedford Pk, IL 60638 708-496-2800
- Malarkey Roofing, 3131 N. Columbia Blvd., Portland OR 97217 503-283-1191
- Owens-Corning Fiberglas, Fiberglass Tower, Toledo OH 43659 419-248-8000
- PABCO Roofing, 1715 Thorne Rd., Tacoma WA 98241 206-272-0374
- TAMKO Roofing, 220 W. Fourth St., Joplin MO 64802 417-624-6644
- Intec/Permaglas, POB 2845, Port Arthur TX 77643 404-724-7024
- NOTE: Some manufacturers may consolidate with others or may have ceased operation.
Where to Report a Failing Asphalt Shingle Roof
Please see ROOFING WARRANTIES for our full discussion of roofing shingle warranties, class actions and settlements, how to report shingle failures, and a shingle failure report form.
If you have a roof failure that appears to be due to a defective product, first try:
- Contact the installing roofer for assistance - s/he may be able to assist with a claim and certainly should want to know if you're having a problem with the roof.
- Contact the building supply company who provided your shingles - they may be able to assist with a claim.
- Contact the roofing manufacturer directly
- For large claims you may need assistance from an independent roofing consultant who can prepare failed-shingle samples, provide photographic and written documentation, and assist you with your claim.
- Roofing material test laboratories can also provide assistance in evaluating damaged roof material but usually this service is too costly for a small residential claim. Beware: there are some excellent independent roofing material test laboratories but if you find a company whose primary customer is the roofing manufacturer they may have a conflict of interest when testing for a supplier, installer, or private building owner.
Roof failure basic field report information for Research Purposes
For research purposes we would also like to receive your reports of roofing product failures as we are actively researching roof failures, repair alternatives, and warranty claims procedures. We seek examples of failures on asphalt shingle roofs and claims experience in New York Pennsylvania Connecticut New Jersey NY PA CT NJ and in California, Oregon, Washington State CA OR WA, (both fiberglass and or non-fiberglass based shingles, GAF and all other brands). You can help by providing information. Email us to send photographs and a description of your roof shingle failure experience as outlined below. Regrettably the volume of web traffic precludes free email, telephone, or other roof failure consulting except that we offer pro-bono or reduced fees for the elderly, disabled, and people of limited means.
Please see ROOFING WARRANTIES for our full discussion of roofing shingle warranties, class actions and settlements, how to report shingle failures, and a shingle failure report form.
- Roof type: e.g. asphalt shingle, fiberglass-based or asphalt shingle, organic-mat based
- Age of roof: date installed, or approximate age if known, or indicate unknown
- Roof Ventilation: none, ridge, soffit, gable-end, roof vents, power vents, blocked/unblocked at eaves or ridge, unknown.
- Shingle color, weight, rated or claimed life expectancy if known.
- City and State where building is located
- Contact information: Name, telephone, Email. Note: contact information is optional. Our privacy policy: 100% private. Your personal information is released to no one. Period.
- Describe conditions under which the roof failed, when the failure was first observed, and what related building damage occurred. Photos are helpful.
- Describe the results you obtained when contacting your roofer for assistance.
- Describe the results you obtained when contacting the roofing product manufacturer or local supplier for assistance.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
- Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
- Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
- The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for this article. All rights and contents are ©Journal of Light Construction and may not be reproduced in any form.
- Architectural elements: the technological revolution: Galvanized iron roof plates and corrugated sheets; cast iron facades, columns, door and window caps, ... (American historical catalog collection), Diana S Waite, available used out of Amazon.
- Asphalt Roofing Residential Manual,
- Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 ISBN-13: 978-0471331728
- Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
- 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
- Handbook of Building Crafts in Conservation, Jack Bower, Ed., Van Nostrand Reinhold Company, NY 1981 ISBN 0-442-2135-3 Library of Congress Catalog Card Nr. 81-50643.
- Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008) ISBN-10: 0471788368 ISBN-13: 978-0471788362
- Patio Roofs, how to build, Sunset Books
- Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used)
- 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. - Smart Guide: Roofing: Step-by-Step Projects, Creative Homeowner (Ed), 2004, ISBN-10: 1580111491, ISBN-13: 978-1580111492
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