Questions & answers about thatch roofing on buildings
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This article describes types of thatch roofing used on buildings, with a brief history of thatch and a focus on contemporary use of this roofing method. This website provides un-biased articles about many common roofing materials, installations, inspection, defects, roofing repairs, and products.
Traditional thatch roofing was constructed of straw, combed wheat, longstraw, broom, sod, and water reed (Phragmites australis). But other plant materials have been used depending on what was readily available in various parts of the world, including palm leaves and plant fragments.
Thatched roofs were typically installed on steep sloped roof structures in order to shed water rapidly (rather than absorbing it).
Our photo (left) shows a palm leaf thatched roof used on the shelter mounted on Thor Heyerdahl's 1947 Kon Tiki Raft. (The Kon Tiki and its shelter are preserved at the Kon Tiki museum in Oslo, Norway.)
Our page top photo shows another palm thatch roof in Veracruz, Mexico in 1972.
Life Expectancy of Thatch Roofs
Our photos (below) show the exterior and also the interior structure a traditional Mexican thatch roof used at the visitors' center of el Charco, an environmental park in San Miguel de Allende, Guanajuato, Mexico (2004). The interior photo (below right) shows how the thatch roof skylight window was constructed. A closeup of this window seen from outside is provided below in this article.
Water reed thatched roofing can last up to 50 years. Combed wheat reed typically has a life expectancy of 25 - 35 years, and long straw 15 - 25 years. For all of these traditional thatch roof types, re-ridging is needed about every 10 - 15 years.
The life of a thatch roof varies considerably depending on the roof slope (shallower or lower pitch thatched roofs are more likely to leak, absorb water, and have a short life), and on the geographic area where the roofed building is located. The typical slope of a thatched roof structure is 50 degrees. But as we explain next, the slope of the roof structure is not the same as the slope of the thatch itself.
The life of a thatch roof is also significantly affected by the thickness of the thatch, since a thicker thatch results in a less-steep angle of the individual reeds or straws. A less steep reed or straw angle results in a shorter roof life. A 9-15" thickness is recommended for a water reed thatch roof and a 9-12" thatch is recommended for wheat reed and longstraw thatches.
Insulating Value of Thatched Roofs is about R-11 for a typical 9-12" thick thatch.
Books & Articles on Thatch Roof Inspection, Installation, Repair, Maintenance, & History
The books listed below can be found by using the "Roofing" link at the InspectAPedia Bookstore.
The Complete Guide to Living with Thatch, Michael Billett, Robert Hale (Publisher) 2003, ISBN-13: 978-0709071587. The author guides the reader through the development of thatching, the materials used, and the artistic work that creates the charm and beauty of a thatched roof.
There are extensive chapters giving a host of practical tips for those living in thatched houses, including the advantages and disadvantages, maintenance, fire precautions, costs, insurance, and more. A glossary reveals the many unusual terms used by the thatcher and there is a list of useful addresses for further advice. The Complete Guide to Living with Thatch contains a wealth of practical information and advice for all those who live in or who are contemplating buying a thatched house.
Thatch and Thatching, Jacqueline Fearne, Shire Library, 2008 ISBN-13: 978-0747805885. The craft of the thatcher probably gives more pleasure to people than any other of our rural crafts. Thatching is a craft most people know nothing about and which is commonly thought to be dying out. In fact, thatchers in all three materials - water reed, long straw and combed wheat reed - now have an assured livelihood after two centuries of uncertainty. This book outlines the history of thatching in Britain from its use as the commonest form of roofing to the present day and explains how the thatcher works with his traditional materials.
"Thatched Roofs - An Introduction," Catherine Lewis, The Building Conservation Directory, 1995
Thatched roof advisory information for the U.K. is at http://www.thatchingadvisoryservices.co.uk
Quick Comparison of Typical Roof Costs, Life Expectancy, Characteristics
Here is a quick comparison of common roofing materials. Our roofing inspection, diagnosis, repair and installation articles listed at left and below provide roof inspection, roof leak or problem diagnosis, roof installation, and roof repair information as well as details about the factors that affect the life of any roof. We include roof warranty and claim information and links to roofing product sources.
Asbestos cement roofing shingles, now replaced with fiber cement roof shingles are similar to slate in durability and costs - see slate roofing below.
Asphalt roofing shingles have an installed cost (including labor) of $100 - $350 per square. (one square covers 100 sq.ft. of roof surface) Asphalt shingles have a typical life expectancy of 15-25 years, with some warranties extending up to 45 years, and asphalt roof shingles typically weigh 225-385 pounds per square.
Clay tile roofing material and installation labor are more expensive than alternate materials, but the material has a life expectancy of up to 350 years where high quality vitreous tiles are used. Clay tiles are heavy, weighing between 850 and 1,700 pounds per square.
Wood roofing shingles 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.
Metal roofing material costs $35 - 250 per square (wide range because of wide range of types of metal roofing), with an installed cost of $35 - $400 / square, a life of 15-40 years or more (a roof kept properly coated can last longer), and weigh 50 - 270 pounds / square. A high end aluminum metal roof may cost $800 - $1000 / square.
Thatch roofing - typical life 15-25 years. Cost varies by geographic locale, roof pitch, materials.
Slate roofing has an installed cost of $900 - $1,000 per square, has a life expectancy of 30 - 100 years (or 300 or more in some cases), and weighs 500-1,000 pounds/square. Synthetic slates cost less, typically $700 -$900 per square.
Membrane roofing such as modified bitumen, rubber, or built up roofing using tar and gravel have a life expectancy of 20 - 40 years, varying significantly depending on materials and workmanship, and may cost $750 to $1000 per square.
Questions & Answers regarding this article
Questions & answers about thatch roofing on buildings.
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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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