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Fiber cement siding maintenance recommendations from Certainteed™, James HardiePlank™ & other sources.
This article describes steps to protect building siding from water damage, plant damage, weather damage in general, giving clearances as well as sealing & caulking advice. We include sources for back flashing and H flashing that can be retrofitted to leaky or loose building siding to improve its weather resistance. Page top photo: Tamlyn's back flashing product recommended when lap siding was installed.
Adapted & excerpted from CertainTeed Corporation's "CertainTeed WeatherBoards™ Fiber Cement Siding Installation Manual" [5a] and from "Fiber Cement Siding Best Practices for Effective Job Site Management"[5b] and from JamesHardie Corporation installation instructions and bulletins for JamesHardie HardiePlank lap siding. [12b]
Moisture Management and Gutters & Fiber Cement Siding Avoids Water Damage
Water management is key to protecting every part of
your home, including your siding. Each area of the
country is affected by moisture, whether it’s an
occasional thunderstorm, high levels of rainfall or
heavy snow accumulations.
The resulting moisture has
potential to cause damage if not managed effectively.
We recommend protecting your home from rainfall with
gutters and downspouts. Divert or remove heavy snow
accumulations that may stand against the siding for
extended periods of time. And you should always be sure
that your drainage system is free of debris and working
Proper moisture management also involves managing
your landscape. Plants hold moisture, so any trees or
shrubs that are close to your home should be trimmed
periodically. Plants should not come into contact with your
siding. Also, sprinkler systems should be adjusted to not
saturate areas near your home.
Clearances for Fiber Cement Siding to Ground, Walks, Patios, Shrubs
Maintain required clearances and drainage slopes to
ensure that moisture is diverted away from your siding
at roof lines and ground level. Proper clearances include
1 inch from concrete, roof lines, patios, etc., and 6
inches from the finished grade. Landscaping should not
reach the siding.
Re caulking Fiber Cement Siding - vs Installing H-Covers to Cover Siding Butt Joint Gaps
It is normal for building products located on the exterior
of a home to expand and contract with temperature
changes. To ensure a successful siding installation,
you must allow for this movement during installation.
While CertainTeed WeatherBoards Fiber Cement siding
does not experience the same rate of expansion and
contraction as many other building products (such
as wood), over time you may notice movement of the
siding, specifically at the butt end/joints. This issue
is mainly an aesthetic issue and should not create a
condition that would cause long-term product failure.
If you are dissatisfied with the appearance of the butt
end/joint locations and wish to address them,
CertainTeed recommends that you apply
H-covers at the joint locations.
You will see vertical lines where each H-cover is installed, but then in our OPINION there were vertical lines already visible at the butt joint. And we agree with CertainTeed that this approach is likely to be more attractive than blobbing or smearing caulk into butt joint openings - a procedure that changes the texture of the siding and its coating performance or re-painting performance and appearance in a way that can be far more ugly, leaving roundish smears at every butt joint so treated.
Watch out: even the H-cover solution to siding board butt joint gaps is not without possible trouble. What are the chances that the plastic or aluminum of the H-cover will weather and change color at the same rate and in the same hue as the paint or coating on the siding boards? I'll bet zero. So over time these covers may become more noticeable.
Details about cures for the cosmetic problem of gaps at lap siding butt joints as well as for wall leaks at these locations are found at SIDING, FIBER CEMENT GAP CURES.
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Questions & answers or comments about the cause & cure of butt joint gaps in fiber-cement siding.
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 " Anyone else have HardiePlank siding on their house?", Early Retirement.org online blog, retrieved 1/14/2013, original source: http://www.early-retirement.org/forums/f27/anyone-else-have- HardiePlank-siding-on-their-house-19475.html
 - DIY Chatroom, retrieved 1/17/2013, original source http://www.diychatroom.com/f2/ certainteed-weatherboard-vs-HardiePlank-4638/
 Certainteed Weatherboard fiber cement siding and trim products - see certainteed.com/ or see certainteed.com/resources/sidingandtrimspecsheet.pdf
[5a] "CertainTeed WeatherBoards™ Fiber Cement Siding Installation Manual", CertainTeed Corporation, 2012, CertainTeed Corporation, PO Box 880, Valley Forge PA 19482, Professional Help Line: 800-233-8990, Consumer Help Line: 800-782-8777, Website: Certainteed.com www.certainteed.com/resources/fc017.pdf retrieved 4/11/2013, [copy on file as Certainteed_Fiber_Cement_Siding_Install_fc017.pdf ]
[5b] "Certainteed WeatherBoards™ Fiber Cement Siding Best Practices for Effective Job Site Management", CertainTeed Corporation, retrieved 4/15/13 original source: www.certainteed.com Copy on file as Certainteed_FC_Handling Brochure-Contractor_FC063.pdf
 "Moisture Control in buildings: Putting Building Science in Green Building," Alex Wilson, Environmental Building News, Vol. 12. No. 5. [Good tutorial, "Moisture 101" outlining the physics of moisture movement in buildings and a good but incomplete list of general suggestions for moisture control - inadequate attention given to exterior conditions such as roof and surface drainage defects which are among the most-common sources of building moisture and water entry.--DJF]
 J. Tibbets, "Green Houses", NCBI, retrieved 1/17/2013, original source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1469482/
 Gleeson et al, "Fiber Cement :Building Materials with Low Density Additives", U.S. Patent 8,182,606, B2 5/22/2012, [adding low volumes of volcanic ash & hollow ceramic microspheres to cellulose fiber-reinforced building materials.
 Thanks to reader Marie Carr for James HardiePlank siding photograph and case history information.
 JamesHardie HardiePlank® Lap Siding information can be found at the company's web page on this material:
 "30-Year Limited Warranty
HardiePlank® HZ5® Lap Siding, HardiePanel® HZ5® Vertical Siding,
HardieShingle® HZ5® Siding, HardieSoffit® HZ5® Panels", 1-800-9-HARDIE
10901 Elm Avenue Fontana, CA 92337, retrieved 1/18/2013, original source: http://www.jameshardie.com/pdf/warranty/hz5.pdf [copy on file as Hardieplank_Warranty_hz5.pdf]
 James Hardie Building Products, James Hardie CustomerLink™ Service Centre, 10 Colquhoun Street, Rosehill NSW 2142, Tel: 13 1103, Outside Australia 61 2 8837 4709,
Fax: 1 800 818 819. Hardie has operations in Australia, Asia, Canada, Europe, New Zealand, United States, and the Philippines. The company is a significant producer of fiber cement siding and backerboard. Email: info@JamesHardie.com and Website http://www.jameshardie.com/
[12b] "Technical Bulletin #9, Joint Flashing at Field Butt Joints", JamesHardie, retrieved 4/15/2013, original source: www.jameshardie.com, copy on file as James_Hardie_9-joint-flashing.pdf - quoting: This Technical Bulletin is an explanation supporting the
announcement made by James Hardie on September 8th, 2008
withdrawing its recommendation on the use of caulk at field butt
joints for HardiePlank® lap siding.
 Instructions for application of HardiePlank lap siding can be found at http://www.jameshardie.com/homeowner/products_siding_hardieplankLapSiding.py?openTab=jsnavLink4
 "Homeowners Care and Maintenance Tips", 1-800-9-HARDIE
10901 Elm Avenue Fontana, CA 92337, included with product warranty information, retrieved 1/18/2013, original source: http://www.jameshardie.com/pdf/warranty/hz5.pdf [copy on file as Hardieplank_Warranty_hz5.pdf]
 "HardiePlank HZ5 Lap Siding Installation Requirements - Primed & Colorplus® Products",JamesHardie, November 2012, 1-800-9-HARDIE,
10901 Elm Avenue Fontana, CA 92337, retrieved 1/18/2013, original source: http://www.jameshardie.com/pdf/install/hardieplank-hz5.pdf, [copy on file as Hardieplank-hz5_Install.pdf]
 Technical Bulletin #9,
Joint Flashing at Field Butt Joints, James Hardie corporation, retrieved 1/19/2013, original source: http://www.jameshardie.com/pdf/technical-bulletins/9-joint-flashing.pdf
 Technical Bulletin #17,
Fastening Tips for HardiePlank® Lap Siding, James Hardie Corporation, retrieved 1/19/2013, original source: http://www.jameshardie.com/pdf/technical-bulletins/17 -fastening-tips-for%20-plank.pdf [copy on file]
 Technical Bulletin #8,
Expansion Characteristics of James Hardie® Siding Products, James Hardie Corporation, retrieved 1/19/2013, original source: http://www.jameshardie.com/pdf/technical-bulletins/8-expansion-characteristics.pdf [copy on file]
 Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: email@example.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions. Personal communication 3/20/2013.
 Johnston, Colin D., Fiber-reinforced cements and concretes. Vol. 3., Taylor & Francis, (CRC Press) 2000. ISBN-10: 9056996940
ISBN-13: 978-9056996949, "This book summarizes and simplifies the results of a considerable body of research and practical experience with a wide range of fiber-reinforced cementitious composites."
 James Hardieplank, personal communication with Daniel Friedman, 6/6/2013. We called James Hardie to ask for guidance in determining just how much moisture was "too much" in Hardieplank siding, after observing that siding at a job arrived visibly wet from the factory even though still inside its original sealed plastic wrapping. We called James Hardie's technical support line where a courteous representative told us he would refer us to Hardie's expert Benjaman Batres. Our call to Mr. Batres was returned by Stephanie (declined to give last name) from James Hardie's customer warranty service department. Stephanie informed us that there are no moisture numbers, that it is not possible to measure moisture in fiber cement siding (utter nonsense!) and repeatedly advised "Just read our instructions" or "So file a claim". Don't count on much help from James Hardie's customer warranty department on siding shrinkage or butt joint gap concerns. Gaps at Hardieplank siding butt joints continue to appear in the Hardieplank installation.
Paint Handbook: testing, selection, application, troubleshooting, surface preparation, etc., Guy E. Weismantel, Ed., McGraw Hill Book Company, 1981, ISBN-10: 0070690618, ISBN-13: 978-0070690615, [Excellent but a bit obsolete paint theory and practice, also a bit light on field investigation methods, out of print, available used-DF] How to select and apply the right paint or coating for any surface. The first major reference to help you choose the correct paint or other finish to do the job best on a particular surface exposed to a particular environment. Experts in the field give full advice on testing surface preparation, application, corrosion prevention, and troubleshooting. The handbook covers wood, metal, composites, and masonry, as well as marine applications and roof coatings. A ``must'' working tool for contractors, architects, engineers, specification writers, and paint dealers.
Paint and Surface Coatings, Theory and Practice, R. Lambourne & T.A. Strivens, Ed., Woodhead Publishing Ltd., William Andrew Publishing, 1999 ISBN 1-85573-348 X & 1-884207-73-1 [This is perhaps the leading reference on modern paints and coatings, but is a difficult text to obtain, and is a bit short on field investigation methods - DF]
Provides a comprehensive reference source for all those in the paint industry, paint manufacturers and raw materials suppliers, undergraduate and postgraduate students, and industrial paint users. R. Lambourne was in the Research Department at ICI Paints Division and the Industrial Colloid Advisory Group, Birstol University, UK.
Sealants, Durability of Building Sealants (RILEM Proceedings), J.C. Beech, A.T. Wolf, Spon Press; illustrated edition (1995), ISBN-10: 0419210709, ISBN-13: 978-0419210702 This book presents the papers given at the RILEM Seminar held at the Building Research Establishment, Garston, UK in October 1994. The book provides an opportunity for researchers to review up-to-date progress towards the achievement of the objectives of the standardisation of laboratory techniques of sealants in the variety of service conditions to which they are exposed.
Staining, Prevention of Premature Staining in New buildings, Phil Parnham, Taylor & Francis; 1996, ISBN-10: 0419171304, ISBN-13: 978-0419171300 The appearance of ugly staining early in a buildings life, ruins an otherwise pleasing appearance, tarnishes the image of the owners and gives rise to costly refurbishment works. In this book Phil Parnham raises a number of questions that should be considered whenever a new building is being designed or built. These are: * why has staining become so prominent; * what causes premature staining; which parts of new buildings are likely to be affected; * how can it be avoided? By using a number of highly illustrated case studies, the author answers these questions and ends by suggesting measures that should be taken by all design and construction professionals to prevent premature staining.
"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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