Installation guide for modular metal shingle roofing
Flashings and Accessories for modular shingle metal roofs
Characteristics of metal roofing materials
Best practices for roofing material installation, flashing, ventilation, nailing, underlayment
This article explains the selection, use, and properties of modular metal roof shingle systems, including granular-surfaced metal roof shingles and snap-together metal roof shingles. We include a photo guide to types of metal roof shingles including antique metal shingles.
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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.
Modular Metal Roof Shingles: Best Roofing Practices & Installation Details
The metal roof shingles at below-right found on a New York home are steel, coated with a granular material that from the ground can be mistaken for asphalt. Carson Dunlop's metal roof shingle sketch (below left) provides additional details about this roofing option.
Modular metal shingles comprise the fastest growing segment
of the metal roofing industry. Using light-gauge steel,
copper, or aluminum, panels are stamped to imitate slates,
shakes, asphalt shingles, or tiles. Some have aggregate
stone finishes that closely resemble asphalt shingles. Most
carry warranties from 20 to 30 years against fading and
from 50-year to “lifetime” warranties against cracking or
delamination of the shingle itself.
Modular shingles carry a Class A or B fire rating,
depending on the material and installation details, and are
highly resistant to wind uplift and damage from hail. Installed
prices range from two to three times the cost of premium asphalt
shingles. Installers accustomed to asphalt shingles or
tile should have little trouble adjusting to metal shingles.
Materials Used in Modular Metal Roof Shingle Systems
Modular shingles are typically stamped from
lightweight .0165-inch metal, which is thinner than other
types of metal roofing but stiffened by the textured patterns.
Typical rectangular panel sizes range from 24 to 48
inches long by 12 to 16 inches wide, but they also include
tile and diamond shapes and other specialty patterns.
The roof shown in our photo (left) was installed in Molde, Norway, an area of challenging winter weather. Here is another Molde, Norway modular shingle metal roof showing a different shingle pattern.
Weights for modular metal shingle roofs range from 40 pounds per square for aluminum
shingles to 140 pounds per square for steel shingles with a
heavy stone aggregate.
The lightweight patterns are well suited
to reroofing where weight is a concern. Most panels
can be walked on, if done with care, but areas with heavy
foot traffic should be reinforced with foam backers provided
by the manufacturer.
Installation Methods for Modular Metal Roof Shingle Systems
Modular shingles are either nailed directly
to the wood deck or attached to 2x2-inch battens installed
at the exposed panel width, usually about 15 inches.
Installation on battens allows more deeply etched patterns,
such as simulated tiles. Either type can be installed with
pneumatic nailers.
Underlayment for modular or "snap together" metal shingle roofs is minimum No. 30 asphalt felt held
with plastic caps to avoid contact between incompatible
metals. Many manufacturers recommend proprietary
laminated underlayments, such as VersaShield (Elk Premium
Building Products, Inc.), which are tougher and less
slippery than felt and provide better fire ratings. Aluminum
shingles require fire-resistant underlayments to achieve an
A or B fire rating.
Direct to Deck Modular Roof Shingle Attachment Method
Direct to deck Modular Metal Roof Shingle Method: Shingle panels installed directly to the
deck are attached with concealed nails, either through
clips or a nailing flange along the top, and have interlocking
edges along all four sides (Figure 2-43 shown at left).
As
they are installed, each panel locks to the panel below
and to the left.
Installing Modular Metal Roof Shingle Over battens
Modular Metal Roof Shingle Over battens: Modular panels designed for installation
on battens have a nailing flange along the bottom of
each shingle panel with nails going horizontally into
the batten (Figure 2-44).
Roof battens are useful for modular metal roof shingle retrofits
where the surface is irregular. Also, the air space
boosts energy savings, especially when using shingles
with solar-reflective surfaces.
Both systems begin with the installation of a drip edge
and gable trim designed for the specific system.
Working
from left to right, the first shingle panel hooks into the drip
edge, which also serves as a starter strip.
Successive
courses for modular metal shingles are staggered as specified by the manufacturer.
Reroofing Using Modular Shingles On Top of Other Roof Coverings
As we discuss at METAL ROOFING, the rusted metal shingles on the church roof (Clintondale, NY) shown in our photo (left) demonstrate more about the history of how metal roofing was used in the U.S. Here the original wood shingle roof was re-roofed using metal shingles, probably before 1900.
In general, most modular shingles can be installed
over existing asphalt shingles [or wood or some other surfaces] if they are in good
condition without excessive curling and deformation.
Metal modular roof shingles that are designed to go over battens (see above) have more flexibility,
since the battens can be shimmed to create a level surface.
Flashing and Sealing Details for Modular Metal Roof Shingles
Manufacturers provide standard
flashings similar to those for standing-seam products.
Eaves and rake flashings typically have concealed fasteners
and lock the shingles in place.
Ridge and headwall
flashings often require exposed fasteners.
Depending on
the shingle profile, sidewall, chimney, and skylight flashings
are either pan or step flashings.
Typical flashing and sealing details for metal modular roof shingles are
shown at left in Figure 2-45.
[Click any image or table for a larger and more detailed view.]
Metal roofing in America is principally a
19th-century phenomenon. Before then the
only metals commonly used were lead and
copper. Tin-plate iron, commonly called "tin
roofing," was used extensively in Canada in
the 18th century, but was not commonly used
in the United States until rolling mills were
established in this country. The low cost, light
weight, low maintenance and ease of shipping
of tin plate made it a common roofing
material.
Embossed tin shingles, whose
Grapevine Design Guidelines – Roof Design Guidelines 4.9 - 2
surfaces created interesting patterns, were
popular throughout the country in the late 19th
century. Tin roofs were often kept well-painted
in red or green to imitate the green patina of
copper. Unfortunately, few of these roofs
remain intact today.
Similar snap-together metal roof shingles made of copper are discussed at COPPER ROOFING.
Soldered Flat Shingle and Flat Copper Metal Roofs
Flat metal shingles with interlocking edges were produced in both steel and copper, then soldered when in place. Usually we find these installed on flat or low-slope roofs such as at dormer insets on homes constructed in the U.S. before 1920.
Carson Dunlop's standing seam metal roof sketch (below) includes a sketch of soldering used to connect flat metal roofing panels.
Watch out: large expanses of metal roofing with soldered connections may flex and break open the soldered joints due to thermal movement.
Classic Products
www.classicroof.com
Modular metal shingle panels and standing seam panels
Decra Roofing Systems
www.decra.com
Modular metal shingle, tile, and shake panels
Dura-Lok Roofing Systems
www.duraloc.com
Modular metal roofing shingles with granular coating
Fabral
www.fabral.com
Exposed fastener and concealed clip metal roofing
panels
Gerard Roofing Technologies
www.gerardusa.com
Modular metal shake and tile panels with granular
coating
Met-Tile
www.met-tile.com
Modular metal roof-tile panels
Atas International
www.atas.com
Modular metal shingle, tile, and standing-seam panels
Custom-Bilt Metals
www.custombiltmetals.com
Modular metal shakes and standing seam panels
Zappone Manufacturing, website www.zappone.com/
Zappone Manufacturing, 2928 North Pittsburg St. Spokane, WA 99207
1-800-285-2677, Washington State Copper Roofing Supplier of
Copper scallop shingles, copper shingles, copper bay windows, vertical walls, aluminum roof shingles
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
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.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or 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.
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.
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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