InspectAPedia offers impartial, unbiased advice without conflicts of interest.
We will block advertisements which we discover or readers inform us are associated with bad business practices,
false-advertising, or junk science. Our contact info is at
InspectAPedia.com/Contact.htm.
Our photo (above) shows a flat concrete roof under construction in San Miguel de Allende, Mexico. This article describes several approaches to constructing concrete roofs, including flat concrete roofs, low-slope concrete roofs, and a steep pitch concrete roof.
Concrete tiles were introduced to the United States in the
early 1900s, but they did not catch on until the 1960s. They
now account for more than half the tiles sold in the United
States. In Europe, over 90% of new houses have concrete
tile roofs. Concrete tiles cost as little as half as much as
clay and offer both traditional and flat styles that simulate
slate roofing and wood shakes.
High-quality concrete tiles should last up to 50 years in
arid climates and up to 30 years in hot, humid climates.
While some early products faced problems with freeze-thaw
cycling, most newer formulations are made to withstand
winter weather. In cold climates, make sure the product is
warranted for freeze-thaw durability.
Special lightweight concrete tiles weighing under
600 lb per square are gaining in popularity. Although they
cost more than standard concrete tiles and are more prone
to breakage, they are easier to handle and suitable for
applications where the roof structure cannot support
the weight of standard tiles. Lightweight tiles cannot
support foot traffic without adding walking pads to distribute
weight or filling the space under the tiles with
polyurethane foam. They are also not recommended
for high-snow regions.
The concrete roof approach shown at left is the structure supporting the flat concrete roof being poured and finished at the top of this page.
The El Charco concrete roof approach shown below was stained brown to resemble an antique thatch roof used on other slopes of the same building. This roof, located in San Miguel de Allende, Mexico, incorporates a large concrete gutter that collects rainwater for local use.
The concrete Taboada Hot Springs (Guanajuato, Mexico) roof approach shown below has been in use in central Mexico since at least 1740 and combines fired clay tiles (below right), concrete or wood rafters, and a top pour of concrete (below left).
Guide to Concrete, Clay, or Metal Roof Tile Shapes, Colors & Types
Concrete tiles can be surface colored with a slurry
of iron-oxide pigments applied to the surface or have the
color added to the concrete mix for a more durable, and
expensive, through-color. Through-color choices are more
limited, and the colors are more subdued. Either type of
concrete tile is also sealed with a clear acrylic spray to help with
curing and efflorescence.
While the color-through concrete roof tile will
hold its color better than the slurry type, particularly under
freeze-thaw cycling, all concrete tile coloring can be expected
to fade and soften over time. Surface textures can
also be added to flat concrete roofing tiles to simulate wood shakes
or shingles.
The illustration of of types or styles of concrete roof tiles (left) was provided courtesy of Carson Dunlop Associates and illustrates
Flat profile concrete roof tiles (the roof tile surface rises by up to 1/2 inch) - these roof tiles often resemble slate or even wood shakes.
Low profile concrete roof tiles: the height of the tile is 1/5 the tile width or less
High profile concrete roof tiles: the height of the roof tile is more than1/5 its width
Common high-profile roofing tiles include
two-piece pan-and-cover Mission tile and one-piece Spanish
S-tiles.
Low profile roof tile styles include a wide variety, many with
a double-S shape that creates multiple water courses.
Many
flat roof tiles are shaped and colored to simulate slate or wood
shakes. In general, patterns using smaller tiles cost more per
square for both materials and labor than patterns using larger
tiles.
How Concrete Roof Tiles are Secured to the Roof Deck
As Carson Dunlop's drawing shows, concrete roof tiles are secured to the roof deck using one of three methods:
The concrete roof tiles are nailed to roof battens running parallel to the roof eaves. Gaps are left in the battens so that water passing through the tiles drains down tothe eaves, and a waterproof membrane is below the battens.
Concrete roof tiles may be secured by a combination of nailing to the roof deck and concrete. This is the method used also to secure clay roof tiles on some Florida homes such as the Boca Raton Roof shown here.
Hurricane clips are recommended or often required by local building codes in hurricane prone areas. The clips are fastened to the roof deck, usually with multiple fasteners, and clip to edges of the roof tiles. In high wind and hurricane areas the number of fasteners is also increased.
On older clay and concrete tile roofs it was common practice to nail only every fourth tile, and in areas where high winds are not common, such as on these homes in Patzcuarso Mexico, only the tiles at the roof perimeter are secured at all.
To install concrete roofing tiles in high wind areas, areas of hurricanes or seismic areas, see the roofing tile connecction methods discussed atCLAY TILE WIND & SEISMIC CONNECTORS
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.
"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)
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.
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.)
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).
"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
Mobile View
