Flashing details for clay tile roofs: this article describes the special connection methods used seal or close the ridge, hip, and rake sections of clay tile roofs.
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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. Also see our home page for clay tile roofing, starting at CLAY TILE ROOFING.
Because of the longevity of a tile roof, high-quality flashing
materials should be used. The International Residential
Code calls for a minimum 26-gauge metal. Galvanized
steel should have a minimum of 0.90 ounces of zinc per
square foot (G90 sheet metal). More expensive options include
prepainted galvanized steel or 16-ounce sheet copper.
Tile Roof Details Recommended at Openings and Walls
At walls, dormers, chimneys,
and other vertical surfaces, extend the flashing up at least
6 inches and counterflash.
Extend the clay tile flashing under the tile a
minimum of 6 inches or as specified by the tile manufacturer.
With flat style clay shingles, use step flashing with a minimum
6-inch vertical leg and 5-inch horizontal leg with a
hemmed edge.
Profile style clay tiles along a wall should receive
channel flashing turned up at least one inch on the lower
flange (Figure 2-32 shown at left).
Pipe Flashing Requirements on Tile Roofs
Pipe flashings protruding through a clay tile roof generally get both a primary
flashing when the underlayment is installed and a
secondary soft-metal underlayment that conforms to the
tile.
For profile style clay roofing tiles, this can be 2 1/2 -pound lead or dead-soft
aluminum with an 18-inch-wide skirt (Figure 2-33 shown here).
Valley Details for Tile Roofs
According to the International Residential Code (IRC),
valley flashing in tile roofs should extend at least 11 inches
each way from the valley centerline, and the flashing
should have a formed splash diverter at the center at least
one inch high.
The code requires a minimum underlayment
at the valley of 36-inch-wide Type I No. 30 felt in addition
to the underlayment for the general roof areas. In cold climates
(average January temperature of 25°F or less), a
self-adhering bituminous underlayment is recommended.
Battens, if used, should stop short of the valley metal.
Tiles along the valley edge may be laid first and cut
in place along a chalked line. Cut pieces are attached by
roofing cement or a code-approved adhesive, or they may
use wire ties, tile clips, or batten extenders.
Open Valley Details on Tile Roofs
Open clay tile roof valleys on clay or other tile roofs permit free drainage and
are recommended in areas where leaves, pine needles, and
other debris are likely to fall on the roof.
They are also
recommended in areas subject to snow and ice buildup.
The open valley on this New York clay tile roof shown at above left has been patched more than once. At right our photo of an open valley on a clay tile roof demonstrates how a snow guard can block drainage of a roof valley, leading to debris clogging.
The valley flashing for a tile roof should have hemmed edges and be installed
with cleats that allow individual sections to expand
and contract (Figure 2-34).
Closed Valley Details on Tile Roofs
In this type of valley, the flashing carries
the runoff and the tile in the valley is only decorative.
These are not recommended where debris from trees may
fall on the roof or where the two roof planes joining at the
valley have different pitches or length, causing uneven
flows.
Our photograph of a closed tile roof valley was taken at a home in Surprise, Arizona, in an area where there were few trees or any other leafy plants.
Foot Traffic Advice for Walking on Clay Tile Roofs
To prevent breakage, walk on tiles with extreme caution.
Profile tile and lightweight tile are the most vulnerable,
and concrete tiles are more fragile when they are freshly
manufactured or “green.” If possible, place antennas and
other roof-mounted equipment where it is easy to access
without crossing many tiles.
When it is necessary to walk
on tiles, step only on the head-lap (lower 3 inches) of each
tile. With Mission- or S-tiles, it is best to step across two
tiles at once to distribute the weight. When significant
rooftop work is required, place plywood over the tile to
distribute the load.
Watch out: our own experience is that it is absolutely impossible to walk on many clay tile roofs without damaging them, particularly soft clay such as the roof type used in Latin America (our photo at left).
For these roofs contractors have to remove sufficient clay tiles to provide a walking area. The removed tiles are replaced as the worker is leaving the work area of the roof.
On some other fragile but not totally fragile roofs such as slate roofs, cement tile, cement-asbestos, fiber cement, and hard-fired ceramic clay tile roofs, contractors suspend a ladder over the roof surface, hanging it from the ridge, and cushioning it off of the roof surface using foam or insulation padding, or contractors work from scaffolding. - Ed.
See ROOF INSPECTION SAFETY & LIMITS where we describe roof safety and roof damage issues when inspecting, repairing, or otherwise walking on clay tiles as well as other roof materials such as asphalt, slate, and wood roofs.
Tips for Replacing Broken Roof Tiles - You'll Need These if You Walk on a Tile Roof
If a roofing tile is cracked, gently lift
the overlapping tile and wiggle loose the damaged tile.
Remove
the roof tile nail, screw, or clip with a slate ripper or hacksaw
blade.
Seal any nail holes with roofing cement and slip
a new tile into place, securing the butt end with an L-hook
or bent copper wire (as shown in Figure 2-35).
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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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/
NRCA - National Roofing Contractors Association - http://www.nrca.net/, 10255 W. Higgins Road, Suite 600,
Rosemont, IL 60018-5607, Tel: (847) 299-9070 Fax: (847) 299-1183
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
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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.
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
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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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