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Roof-over with wood shingles or shakes:
This article discusses re-roofing over other materials using wood roof shingles and shakes. We describe installing wood shingles or shakes over asphalt shingles, or installing new wood shingles or shakes over existing wood shingles or shakes. We list manufacturers & product sources for wood shingle or shake roofing.
Our page top photo shows a wood shingle roof on the historic Mesier Homestead in Wappingers Falls, NY. Or wood roof photo at left illustrates a wood shingle roof that is past end of useful life. This roof needs replacement.
[Click to enlarge any image]
Can we roof-over this surface with new wood shingles or does the roof need to be stripped off?
Under some conditions, shakes and shingles can be installed
over existing roofing, as follows:
Advice for Installing Wood Shingles or Shakes Over Existing Asphalt Shingles
If the existing asphalt
shingles are not overly cupped or deteriorated, split or
rough-sawn shakes can be installed over the shingles using
interlaid strips of felt, as described above. Installing wood
shingles over asphalt, however, requires a ventilating underlayment
such as Cedar Breather or a system of battens
(as shown in Figure 2-47 and Figure 2-48).
Figure 2-48 below. [Click any figure or table to see a larger, more detailed version.]
Advice for Installing Wood Shingles or Shakes Over Existing Wood Shingles
Our wood shingle roof photo at left raises some interesting questions about both the original wood shingle installation and now the question of roof replacement.
The shingles do not look worn compared with our worn-out wood shingle photo shown earlier in this article. But the shingles are badly curled and many are splitting, risking leaks. The roof seems to be failing earlier than one might have expected.
We recommend diagnosing the cause of this problem before re-roofing. Is this wood shingle curling and splitting due to:
A poor quality wood shingle? (click to enlarge this or any image at InspectAPedia)
Improper or inadequate under-roof ventilation? While some roofing standards permit installation of wood shingles over solid plywood decking, where we [DJF] have inspected such installations we've seen wood roof shingle failures occurring in less than 10 years.
Other improper installation details?
A second question is whether or not it would be reasonable to roof-over this existing surface. Without diagnosing the ventilation question first one might hesitate in any case to roof over this surface, but roofing over badly curled roof shingles on an existing roof is asking for trouble.
The new roof may itself be unable to lie flat and the uneven underlying surface may contribute to early splits in the new wood shingles or shakes.
If the shingles are not
badly curled or deteriorated, they can form an adequate
surface for new shingles or shakes.
Watch out: Do not place building
felt under the new shingles as that could inhibit drying,
but if there is a high risk of decay (moist environment,
low slope, overhanging trees), a layer of Cedar Breather
is recommended. Shakes should be installed in the normal
fashion with interlaid felt. Use nails long enough to penetrate
Advice for Installing Wood Shingles or Shakes Over Existing Shakes
In most cases, these will need to be
removed before re roofing, as the surface is too irregular,
and nailing through the shakes into solid sheathing is
More Information about Wood Shingle or Shake Roofing Materials, Methods, Standards
Cedar Shake and Shingle Bureau
Advice for Replacing Individual Lost or Damaged Wood Shakes or Shingles
Reader Question 6/23/14 Kevin P. said:
Lets say that you have a condition in which a storm event has resulted in a handful of broken and/or partially displaced wood shakes on the roof.
What would be the best strategy for replacement of those individual shakes?
Can they easily be spot replaced, or would it require a sequence of events, including a large area of removed shakes either above or below the damaged shake?
Kevin, an experienced roofer who is familiar with wood shake roofs can replace or repair missing or loose shakes in spots without removing large areas of materials.
S/he might have to work from a ridge-hooked and padded ladder on some fragile roofs that can't be walked-on without risking further damage, but key in any event is the use of repair methods similar to that for repairing slates - another non-flexible roof material that doesn't allow you to just "lift up" an upper shingle course to nail a lower shingle in place.
You'll see that using a slate hook or even a simple strip of copper (see our sketch at above left) can allow us to hold new slates (or shakes) in place when just a few spots need repair - a much less invasive and much less costly approach.
See SLATE ROOF REPAIRS for examples of these individual shake or slate replacement methods.
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(June 23, 2014) Kevin P. said:
Lets say that you have a condition in which a storm event has resulted in a handful of broken and/or partially displaced wood shakes on the roof. What would be the best strategy for replacement of those individual shakes? Can they easily be spot replaced, or would it require a sequence of events, including a large area of removed shakes either above or below the damaged shake?
Kevin for better space and to allow an illustration I've moved your question and our reply to the bottom of the article shown above. Keep me posted on how your repair progresses. Use our CONTACT link to send me some sharp photos and I may be able to comment further.
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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).
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
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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.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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