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This website describes signs of wear and age on asphalt roof shingles, focusing here on cupped roof shingles and
how to identify & explain the most-common asphalt roof shingle failures.
These defects occur on organic-mat or fiberglass-mat
asphalt roof shingles. Readers are also invited contribute roof failure information to the web author for research purposes.
web author for research purposes.
Asphalt roof shingles often show cupping (a concave center) - discussed here, curling (raised edges which curl downwards) - discussed on the next page,
and fishmouthing
(raised edge of a shingle tab at its center with little curling) - discussed on a subsequent page [see links at the left of each of our pages].
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.
Cupping asphalt roof shingles (see photos on this page), particularly on organic or felt-based asphalt shingles, are a normal wear pattern that shows
up with shingle age. 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.
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.
Cupped roof shingles are fragile: You should avoid walking on cupped-shingle roofs, particularly in cold weather (shingles are more likely to break). 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.
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Additional technical contributors & reference sources for this article are listed below.
Use links at the left of each page to navigate this document or to view other topics at this website.
Green links show where you are in our document or website. If you just "scroll down" you'll
miss some important articles. See links at page left.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com
Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com
Arlene Puentes, a licensed home inspector, educator, and building failures researcher in Kingston, NY
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book 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. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
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.
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
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.
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).
Solar heating, radiative cooling and thermal movement: Their effects on built-up roofing (United States. National Bureau of Standards. Technical note), William C Cullen, Superintendent of Documents, U.S. Govt. Print. Off (1963), ASIN: B0007FTV2Q
"Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
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