This article describes the requirements for battens on clay tile roofs, and how to stack and lay out tiles for roof installation. 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.
Batten Specifications for Clay Tiled Roofs
Tiles with projecting head lugs can be installed
either directly on the deck or with the lugs fitting over
pressure-treated wooden battens nailed horizontally across
Roof tile battens are typically nominal 1x2 or 1x4 lumber,
but they may be larger to accommodate snow loads or unsupported
spans over counterbattens.
[Click to enlarge any image]
Battens for use on clay tile roofs should be
made from pressure-treated lumber except in very dry climates.
Clay tile roof battens are nailed at minimum 24 inches on-center
with spaces for drainage every 48 inches. Lay out battens
to provide equal courses with a minimum 3-inch head-lap,
unless the tile profile is designed for a specific head-lap.
Watch out: as Smith (NRCA) pointed out, battens shimmed off of the roof deck should be supported 12" o.c. to avoid sagging. -Ed.
Fasten the roof battens with 8d galvanized nails or corrosion-resistant
1 1/2-inch 16-gauge staples with 7/16-inch crowns.
Battens under clay roofing tiles are recommended on roof slopes greater than
7:12 to provide solid anchoring and on slopes below 3:12
to minimize penetration of the underlayment. On low
slopes and in areas subject to ice damming, counterbattens
nailed vertically up the roof slope are also recommended
to promote drainage.
Counterbattens on clay tiled roofs should be minimum
1/4 x 2 inches thick in moderate climates, 3/4
inch thick in areas
subject to ice damming. When battens are nailed directly to
the deck, allow a
1/2 -inch gap every 4 feet or set the battens
1/4 -inch shims placed at each nail (see Figure 2-21 above).
Layout and Stacking Specifications for Tiled Roofs
Lay out the courses so that tile
exposures are equal with a head-lap of at least 3 inches
(unless the tile specifies a different lap).
Snap lines on the
underlayment along the top of each course or along each
batten. One or more vertical lines can also be helpful in
keeping the tiles aligned. Accurate layout is critical with
most tile patterns.
Next, carry tiles up to the roof and distribute the
weight equally across the roof, as tiles weigh as much as
10 pounds each.
Depending on the tile, stacks of about 6 to
10 tiles is workable. Our photos (above-left - DF) shows roof tiles stacked and ready for installation in Mesquite Cove AZ.
If mixing different colored tiles,
arrange bundles with the correct proportions on the ground
before stacking them on the roof.
In the 1990's NRCA's Thomas Smith noted that a paper published in the Proceedings of the 10th Conference on Roofing Technology expressed concern for the lack of conservative roofing industry guidelines for the components of tile roofing systems in the U.S. The recommendations in the then-current NRCA Steep Roofing and Waterproofing Manual indeed included recommendations for tile roof underlayment, fasteners, and metal flashings, but Smith noted that these were "non-conservative" for many areas in the United States (and other locations of challenging weather).
Smith posed some interim batten options to improve the life of tile roof systems, including
Except in hot and dry areas (U.S. desert Southwest for example) use preservative treated battens (as recommended above by Bliss);
Use treated wood for ridge and hop nailers
Use treated wood for strips into which tiles are fastened;
Wood treatment should comply with AWPA Standards C2 and P5 or AWPB LP-2
Use battens 4 feet long with a space of 1/2" between ends of each batten to provide a drainage path for water that passes through the tiles to the underlayment, or provide kerf cuts about 1/4" wide at 2" on center [presumably on the bottom surface of all battens - Ed.] - or
Spacers (shims) can be placed between batten and roof underlayment to hold the batten off of the roof surface using spacers constructed of 2" squares of asphalt shingles or treated wood lath, 12" on center to avoid batten sagging
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Frequently Asked Questions (FAQs) about clay tile roofing procedures to avoid damage
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, 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. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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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
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).