Wood Roof Shingles & Shake Properties
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Characteristics of wood shingle & shake roofing materials
Guide to wood shingle/shake grades & wood species
Wood roof shingle/shake warranties
Best practices for roofing material installation, flashing, ventilation, nailing, underlayment

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This article discusses the properties of wood roof shingles and shakes, including shingle grades, wood species used in roofing, and wood roof shingle or shake warranties. This article series discusses best practices in the selection and installation of residential roofing. This article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons. Our page top photo shows a wood shingle roof on the historic Mesier Homestead in Wappingers Falls, NY.

Also see the roofing article links at page left and our roofing home page: ROOFING INSPECTION & REPAIR.

© Copyright 2012 InspectAPedia.com, Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Wood Roof Shingles & Shakes: Materials, Grades, Properties, Warranties

Adapted/paraphrased with permission from Best Practices Guide to Residential Construction, chapter on BEST ROOFING PRACTICES:

Wood shakes and shingles are traditional American roof coverings dating back to Colonial times. They remain popular in many coastal areas and are common or even mandated in certain historic districts. Traditionally, wood roofs were laid on spaced sheathing, which provided good ventilation around the shingles and contributed to a service life of 30 years or more.

New wood roofs set on solid sheathing have been known to fail in 10 years or less unless the installer takes adequate precautions to allow for good drainage and drying of the wood roofing materials. With installed costs of over $600 per square for premium materials, it is important to design a roof that will last.

Materials Used in Wood Shingle & Shake Roofs

Wood shakes and shingles soak up water through their end grain, dry unevenly in the sun, and slowly erode on the surface from a combination of ultraviolet radiation, wind, and precipitation. In humid conditions, wood shingles may become a breeding ground for moss, lichen, and decay fungi. To survive those harsh conditions, wood roofing should be made from a durable wood species that is either naturally decay-resistant or pressure-treated.

Wood Species for Wood Shingle or Shake Roofs

The most commonly used wood on roofs today is western red cedar. The heartwood of red cedar is rich in extractives that provide natural decay resistance. Eastern white cedar also has good decay resistance and is commonly used on the East Coast. However, white cedar is typically flat-sawn and has a mix of heartwood and sapwood, making it less durable on a roof and more prone to cupping and splitting. Other less common species with good track records are Northern white cedar, Alaskan yellow cedar (actually a cypress), and white oak.

Whatever species is selected, use the best grade available. With red cedar and other decay-resistant species, the heartwood is far more decay-resistant than the sapwood. Edge-grain wood is more stable and less prone to cupping and splitting than less expensive flat-grain wood. The best choice for wood roofing is all-heart, edge-grained shakes or shingles.

Wood Shingle & Shake Shingle Grade Choices

Make sure the lumber to be purchased has been graded under the authority of a recognized grading agency such as the Cedar Shake and Shingle Bureau for red cedar or the Southern Pine Inspection Bureau for yellow pine. A blue label on the packaging, for example, may simply be a marketing tactic and does not necessary indicate that the shakes or shingles are certified as Grade 1.

Wood Shingle & Shake Roof Warranties

If installed in accordance with the Cedar Shake and Shingle Bureau’s specifications by a certified installer, the CSSB will guarantee wood roofing for 20 to 25 years, depending on the thickness of the shake or shingle. Some pressure-treated shakes and shingles carry warranties of up to 50 years.

Preservative Treatment for Wood Shingle or Shake Roofs

If premium red or white cedar is too expensive, consider pressure-treated southern yellow pine shakes and shingles. In its favor, yellow pine is a tougher and stronger wood, and although not as pretty as red cedar when new, over time they will both weather to a similar silver gray. Because penetration of the treatment is nearly 100%, pressure-treated pine shingles carry guarantees against decay for up to 50 years, making them well suited to high-moisture environments, shallow slopes, and shady wooded sites where organic matter may collect on the roof. The preservatives should not leach out over time.

One drawback to yellow pine shingles and shakes is that many are flat-grained, so most come pretreated with a water repellent to help them resist cupping and splitting. However, retreatment with a water repellent at some point may be required for optimal performance. Western red cedar shingles are also available pressure-treated for severe applications where standard cedar shingles are prone to decay.

More about preservatives and treatments for wood shingles and shakes is detailed at WOOD ROOF COATINGS & FIRE RATINGS and at WOOD ROOF MAINTENANCE.

Characteristics & Grades of Wood Roof Shingles

Shingles are sawn from blocks of wood, which gives them two smooth faces. They are relatively thin and cut to a taper. Red cedar shingles come in four grades, but most roofs use No. 1 or No. 2, which are all edge-grain heartwood (Table 1-6 below). They are available rebutted and rejointed (R&R), where a uniform appearance is desired, or machine-grooved for a textured surface.

[Click any image or table for a larger, more detailed version.]

Table 1-6: Western Cedar Shingle & Shake Grades (C) J Wiley, S Bliss

Eastern white cedar shingles are also available in four grades. Most roofing work uses Grade A (Extra), which is all-clear, all-heartwood, or Grade B (Clear), which has no knots on the exposed face (see Table 1-7 shown below).

Table 1-6: White Cedar Shingle & Shake Grades (C) J Wiley, S Bliss

Characteristics & Grades of Wood Roof Shakes

Shakes are split from large blocks of wood and may be resawn to create a taper. They are heavier than shingles, less uniform in thickness, and are generally rough-textured on one or both sides creating a more rustic appearance. Grades and characteristics for red cedar shakes and shingles are found in Table 1-6 shown earlier. Red cedar shakes come either tapered or untapered and are usually installed on roofs in Premium or No. 1 grade.

Fire-Retardant Treatment for Wood Shingle Roofs

Once popular on the West Coast, wood roofs have been banned in many residential areas by fire regulations designed to slow the spread of wildfires.

Fire-retardant treated (FRT) shingles and shakes have been developed to address these issues and can obtain a Class B or C rating when combined with other components in a fire-resistant roof system. With pretreated shingles, consult with the treating company regarding fastener requirements and any special application instructions.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Resources: Roofing Materials & Equipment Suppliers

Manufacturers

Ridge Vents

Air Vent/A Gibraltar Company www.airvent.com A complete line of roof ventilation products, including shingle-over and exposed-ridge vents with exterior wind baffles and internal weather filters. Also soffit and drip edge vents and passive and powered attic turbine-type vents.

Benjamin Obdyke www.benjaminobdyke.com Shingle-over ridge vents. Low-profile Roll Vent uses nylonmatrix. Extractor vent is molded polypropylene with internal and external baffles.

Cor-A-Vent www.cor-a-vent.com Shingle-over low-profile ridge vents, including Cor-a-vent, Fold-a-vent, and X-5 ridge vent, designed for extreme weather. Corrugated core.

GAF Materials Corp. www.gaf.com Cobra vent: roll-out shingle-over ridge vent with a polyester-matrix core 102 CHAPTER 2 | Roofing

Mid-America Building Products www.midamericabuilding.com Ridge Master and Hip Master shingle-over molded plastic ridge vents with internal baffles and foam filter

Owens Corning www.owenscorning.com VentSure corrugated polypropylene ridge vents; also passive roof vents and soffit vents

Trimline Building Products www.trimline-products.com Shingle-over low-profile ridge vents, Flow-Thru battens for tile roofs

Elk Premium Building Products www.elkcorp.com Highpoint polypropylene shingle-over ridge vents

Tamko Roofing Products www.tamko.com Shingle-over ridge matrix–type Roll Vent and Rapid Ridge (nail gun version) and Coolridge, which is molded polypropylene with external and internal baffles

Venting Underlayments

Benjamin Obdyke www.benjaminobdyke.com Cedar Breather, a 3/8 -in.-thick matrix-type underlayment designed to provide ventilation and drainage space under wood roofing

More Information about Roofing Materials, Methods, Standards

Asphalt Roofing Manufacturers Association (ARMA) www.asphaltroofing.org

Cedar Shake and Shingle Bureau www.cedarbureau.org

Metal Roofing Alliance www.metalroofing.com

Tile Roofing Institute www.tileroofing.org

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-- Adapted with permission from Best Practices Guide to Residential Construction.

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InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
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BEST PRACTICES GUIDE to Residential Construction
BEST ROOFING PRACTICES

WOOD SHAKE & SHINGLE ROOFING
  WOOD ROOF COATINGS & FIRE RATINGS
  WOOD ROOF INSPECTION GUIDE
  Wood Roof Wear or Installation Problems
  Wood Roof Moss & Lichens
  WOOD ROOF INSTALLATION SPECS
  Wood Roof Flashing Details
  Wood Roof Hip & Ridge Details
  WOOD ROOF LIFE EXPECTANCY
  WOOD ROOF MAINTENANCE
  WOOD ROOF SHAKES INSTALLATION
  WOOD ROOF SHEATHING, UNDERLAYMENT
  WOOD ROOF SHINGLE PROPERTIES
  WOOD SHINGLES, RE-ROOFING WITH

ARMA - Asphalt Roofing Manufacturer's Association - http://www.asphaltroofing.org/
750 National Press Building, 529 14th Street, NW, Washington, DC 20045, Tel: 202 / 207-0917
ASTM - ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA, 19428-2959 USA The ASTM standards listed below can be purchased in fulltext directly from http://www.astm.org/
Cedar Shake & Shingle Bureau, CSSB, U.S.: Sumas, WA 98295-1178, Tel: 604-820-7700, In Canada: Cedar Shake and Shingle Bureau #2 - 7101 Horne Street, Mission, BC V2V 7A2 Tel: (604) 820-7700, E-mail: info@cedarbureau.com , website: http://www.cedarbureau.org/
Forest Products Laboratory, US FPL, One Gifford Pinchot Drive, Madison, WI 53726, Tel: (608) 231-9200, Email: mailroom_forest_products_laboratory@fs.fed.us608-231-9200, website: http://www.fpl.fs.fed.us/
NRCA - National Roofing Contractors Association - http://www.nrca.net/, 10255 W. Higgins Road, Suite 600, Rosemont, IL 60018-5607, Tel: (847) 299-9070
UL - Underwriters Laboratories - http://www.ul.com/
2600 N.W. Lake Rd.
Camas, WA 98607-8542
Tel: 1.877.854.3577 / Fax: 1.360.817.6278 E-mail: cec.us@us.ul.com

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, and from the InspectAPedia bookstore. The 2010 edition of 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.

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
Built-Up Roof Systems, Manual, C.W. Griffin, Mcgraw-Hill (Tx); 2nd edition (July 1982), ISBN-10: 0070247838, ISBN-13: 978-0070247833
Concrete Folded Plate Roofs, C. Wilby PhD BSc CEng FICE FIStructE (Author), Butterworth-Heinemann, 1998, ISBN-10: 0340662662, ISBN-13: 978-0340662663
Concrete Shell Roofs, C. Wilby PhD BSc CEng FICE FIStructE (Author),
Concrete Dome Roofs (Longman Concrete Design and Construction Series),
Concrete Roofing Tile, History of the, Batsford, 1959, AISN B000HLLOUC (availble used)
Copper Roofing, by CDA
Copper Roofing, Master specifications for copper roofing and sheet metal work in building construction: Institutional, commercial, industrial, I.E. Anderson, 1961 (hard to find)
Corrugated Iron, Building on the Frontier, Simon Holloway
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
Historic Slate Roofs : With How-to Info and Specifications, Tina Skinner (Ed), Schiffer Publishing, 2008, ISBN-10: 0764330012 , ISBN-13: 978-0764330018
Low Slope Roofing, Manual of, 4th Ed., C.W. Griffin, Richard Fricklas, McGraw-Hill Professional; 4 edition, 2006, ISBN-10: 007145828X, ISBN-13: 978-0071458283
- Roof failure causes in depth (and specific methods for avoiding them)
- Roof design fundamentals and flourishes, based on voluminous industry research and experience
- New technologies and materials -- using them safely and correctly
- Comprehensive coverage of all major roofing systems pecifications, inspection, and maintenance tools for roofing work
Metal Roofing, an Illustrated Guide, R.A. Knowlton , [metal shingle roofs],
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.
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).
Slate Roofing in Canada (Studi4es in archaeology, architecture, and history),
Smart Guide: Roofing: Step-by-Step Projects, Creative Homeowner (Ed), 2004, ISBN-10: 1580111491, ISBN-13: 978-1580111492
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
Tile Roofs of Alfred: A Clay Tradition in Alfred NY
"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
Wood Shingle Roofs, Care and Maintenance of wood shingle and shake roofs (EC), Stanley S. Niemiec (out of print)
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Wood Roof Shingles & Shakes: Materials, Grades, Properties, Warranties

Materials Used in Wood Shingle & Shake Roofs

Wood Species for Wood Shingle or Shake Roofs

Wood Shingle & Shake Shingle Grade Choices

Wood Shingle & Shake Roof Warranties

Preservative Treatment for Wood Shingle or Shake Roofs

Characteristics & Grades of Wood Roof Shingles

Characteristics & Grades of Wood Roof Shakes

Fire-Retardant Treatment for Wood Shingle Roofs

Resources: Roofing Materials & Equipment Suppliers

Manufacturers

Ridge Vents

Venting Underlayments

More Information about Roofing Materials, Methods, Standards

Questions & Answers regarding this article

Ask a Question or Search InspectAPedia

Technical Reviewers & References

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Wood Roof Shingles & Shake Properties
InspectAPedia^® -