Key design details & references for wood shingle roofs
Wood roof inspection checklist
Questions & answers about wood shingle roofing
Here we illustrate and discuss the installation, inspection, diagnosis, & repair of wood shingle & wood shake roofing in historic and contemporary use, we describe proper wood shingle or wood shake roof installation details, and we provide a wood roof inspection checklist.
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Our page top photo shows a lichens and moss covered roof located in Key West, Florida, viewed from the Key West lighthouse.
If you are not sure of the difference between a wood shingle and a wood shake, wood shingles are saw-cut and have smooth flat surfaces, while wood shakes are split (by hand or by machine) to produce a thicker and more irregular product. As Carson Dunlop point out in their Home Reference Book, most wood shingles are white cyprus (most durable), cedar (western red cedar or white cedar) but in some locales redwood shingles are also used, and white pine shingles, yellow pine,and spruce have been used. Also see WOOD ROOF INSTALLATION SPECS and see WOOD ROOF SHAKES INSTALLATION.
According to the US NPS "Roofing for Historic buildings":
Wood roofing shingles were commonplace in early America not only because of the abundance of timber, but also because of the relative ease with which they could be fabricated and installed. Made from the heartwood of a variety of locally available trees, early shingles were hand split with a mallet and froe and then dressed or smoothed with a draw knife to ensure they would lay flat on the roof.
The introduction of water and, then, steam powered saws in the early 19th century revolutionized the shingle industry by making possible the mass production of uniformly cut and smoothly finished shingles that required no hand dressing. As early as 1802, for example, N. Combes of Lamberton, New Jersey, informed the public that he now had a shingle dressing machine that had been newly invented by 'D[avid] French of Connecticut. This machine at one stroke shaves the Shingle complete; at the second stroke it joints the same, and this done much more complete than it is possible to have it done by hand, in the usual way (The True American, Trenton, December 6, 1802).
The number of inventions for new types of shingle machines, as well as refinements to existing ones, quickly multiplied as the century advanced; at least nineteen patents were issued in 1857 alone for shingle making machines.
Despite such technological advances, hand split shingles never entirely disappeared. In fact, during most of the 19th century a thriving split shingle industry existed in southern New Jersey. Interestingly, much of the wood used in these shingles came from white cedar logs that had been buried in swamps and then "mined" or raised by shinglers who probed the area for suitable logs.
Reportedly a good shingler could tell merely by smell whether a log had been blown down or broken off, the former being the more desirable since it was less likely to be decayed. Once loosened from the peat, the log floated in the water, where it was sawn into blocks and then split into shingles. An expert worker could mine and shave up to 1,000 shingles a week. Besides supplying local markets, South Jersey's mined shingles were shipped to cities and towns up and down the Delaware River, including Philadelphia.
Although wood shingles received strong competition from other roofing materials in the 19th century, they enjoyed renewed popularity in the late 19th and early 20th centuries with the introduction of the various revival styles of architecture. Wooden shingles were steamed and bent to resemble thatched roofs on Tudor Revival homes, laid in evenly spaced overlapping horizontal rows on Colonial Revival houses, and used with abandon on the roofs and sides of Shingle Style buildings.
Today, although wood shingles represent a relatively small percentage of the roofing market, they remain a fashionable material for custom houses as well as restoration projects.
Wood roofing shingles and shakes material cost $150-200 per square, with an installed cost of $130 - $160 / square. Wood shingle roofs have a typical life expectancy of 10-40 years, and weigh 300-400 pounds per square. The life of a wood shingle roof can vary widely depending on the wood species of shingles used and the treatment of wood roof shingles with preservative.
Wood shingles are sawn in 16", 18" and 24" lengths and are installed overlapped to produce three layers of shingle material covering the roof. Wood shakes (a split rather than sawn product) are thicker than sawn wood shingles (but can still have splitting or installation defects).
Five wood species are cut or split into shingles or shakes: cypress wood shingles (rot resistant but need preservative treatment, red cedar wood shingles, (naturally durable on roofs), redwood roof shingles (rot resistant but need preservative treatment), SYP or southern yellow pine shingles (not usually used on roofs), and white cedar shingles (should not be used on roofs because of its short life in that application.
Carson Dunlop's sketch (left) illustrates a source of variation in the quality of wood shingles that depends on how the shingles are cut from the log. The Carson Dunlop sketch at right illustrates the different qualities of wood shingles and wood shakes used on roofs.
Details about wood shingle and wood roof shake quality, types, warranties, & treatments are found at WOOD ROOF SHINGLE PROPERTIES.
Preservatives & Fire Retardants Used on Wood Shingle or Shake Roofs
Wood roof preservatives can make a significant difference in the life expectancy (and in some cases fire resistance) of wood shingle or wood shake roofs, depending on the wood species of the shingles or shakes (see above) and the preservative used.
Traditionally wood shingle and shakes were treated with copper or copper arsenate compounds to resist insects and rot; some shingle and shake treatments include chemicals that help the roof resist oxidation from sun exposure as well.
Traditional CCA wood treatments turned the roof shingles or shakes green, a color that bleached out to a more natural color after a few months. Contemporary wood roof treatments may not turn the roof green, but they may include pigments that assist in resistance to sunlight and oxidation. Other wood roof preservatives used tin compounds instead of copper, a less long-lasting treatment, and current treatments may use borate salts. Common current wood shingle and shake preservative treatments use products that combine a water repellant, pigment, and a preservative chemical. Pre-treated wood shingles and shakes are provided by some wood roof manufacturers: these products should not require additional coatings.
Watch out: we do not recommend using paints (such as alkyd or latex paint) on wood shingles, especially on wood roofs. Painting one side of wood roof shingles or shakes may accelerate their wear (shorten the roof life) by interfering with shingle or shake drying when the roof becomes wet. Painted roof shingles may split prematurely.
Chemical treatments for wood roofs are required (if wood shingle or shake roofs are permitted at all) in certain dry areas or areas prone to wildfires such as California. If you live in a high fire-risk zone and want the appearance of a wood shingle or shake roof, investigate roof shingles made of recycled materials and sold in products that look like wood shakes or slate.
In order to restore some of
Pennsylvania’s historic buildings,
the authors are recovering a lost
trade practice.
Over the past decade of working on
side-lap-shingle roofs, the authors have
observed many earlier attempts by
others to make the process of replicating
these roofs faster and less expensive.
These attempts have included substituting
materials, sawing and planing shingles
rather than riving them to speed the
manufacturing process, and adding
other materials between courses to
reinforce the roofing system. All of
these attempts have saved money and
time in the short term but have failed to
perform long enough to realize the
savings.
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Additional technical contributors & reference sources for this article are listed below.
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"Choosing Roofing," Jefferson Kolle, January 1995, No. 92, Fine Homebuilding, Taunton Press, 63 S. Main St., PO Box 5506, Newton CT 06470 - 800-888-8286 - see http://www.taunton.com/FineHomebuilding/ for the magazine's website and for subscription information.
Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used)
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/
CCSB offers wood shingle installation instructions in the form of a manual - cedarbureau.org/installation/wall_manual/introduction.htm
"Treatment of Cedar Shakes and Shingles," David Flickinger, RRO, Professional Roofing, October 1999, Rosemont IL.
Sharon C. Park, Preservation Brief 19: The
Repair and Replacement of Historic Wooden
Shingle Roofs (Washington, D.C.: U. S. Dept.
of the Interior, 1989), 6.
Johan Heinrich Jonas Gudehus, “Journey to
America” (1829), trans. Larry M. Neff, re-
printed in the Publications of The Pennsylvania
German Society 14 (1980), 307. “The houses
of the Americans as well as their farm buildings
have wooden shingle roofs that are so thick
and solid that a ray of light can come through
nowhere. These roofs are painted red, brown
or dark blue with oil color and on most of
them is to be found a lightning rod…”
Robert C. Bucher, “The Long Shingle,”
Pennsylvania Folklife 18, no. 4 (summer 1969):
51–56. This article was the first study of side-
lap shingles and the primary source of basic
information for "Fabricating and Installing ... " above.
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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