Fiberboard Building Sheathing Water Protection Protect Insulating Board Sheathing From Water Damage
PROTECT FIBERBOARD from WATER - CONTENTS: importance of protecting Celotex®, Homasote®, Masonite® Nu-Wood® and other insulating fiberboard building sheathing products from water or from getting wet or soaked
POST a QUESTION or READ FAQs about fiberboard building sheathing: how to identify fiberboard products, fiberboard uses, fiberboard, Celotex, Homasote, Insulite & other brands, fiberboard ingredients, does fiberboard contain asbestos?
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Protect fiberboard insulating sheathing from water & water damage:
This article explains the importance of protecting fiberboard sheathing and insulating board from getting soaked - water can damage fiberboard products.
We also answer questions about fiberboard water resistance, fiberboard recycling.
This article series includes the definition, ingredients, history, use, fire resistance & insulating properties of fiberboard sheathing. This article series also describes and provides photographs that aid in identifying various insulating board sheathing materials used on building walls and roofs, such as Homasote, Celotex, Insulite, and Masonite insulating board sheathing products.
Importance of Protecting Fiberboard Insulating Sheathing from Water
[Click to enlarge any image]
Question: can you seal Celotex board in the attic? will sealants harm it?
Can you seal the celotex board in the attic, does it have a negative affect on the Celotex - Steve 3/16/2012
Reply: sealing insulating fiberboard is not necessary - it is moisture resistant - but insulating fiberboard should be kept dry during construction and protected by a moisture barrier between wall siding and the sheathing
Steve, if you are asking about painting Celotex or similar fiberboard products, you can do so, but with the caveat that unless you use a suitable paint, perhaps a lacquer primer/sealer such as BIN, you may get brown bleed-through of the material.
Paint won't injure the board nor harm its insulating properties, though it might slightly affect its sound insulating properties.
If you are sealing to try to reduce moisture uptake I'll add that these products have usually been built or treated to make them water and moisture resistant.
Paraffin and asphalt are common ingredients that add water resistance to fiberboard insulation, and according to the US FPL, the commercial standard for insulating fiberboard placed a limitation of 10% on water absorption for sheathing purposes, and 7 to 10% when the board was used as lath for plaster interior walls, roof boards, or as an interior finish surface. The FPL found that
None of the [fiberboard insulating] boards investigated ... exceeded a moisture absorption of 2.2%
From this and from our warning just below you will see that seal-coating an insulating fiberboard as a move to reduce moisture uptake is unnecessary in normal use as long as the material has been protected from soaking during construction and is installed with a proper wall-moisture barrier [housewrap] between the sheathing and finish wall siding.
If your insulating board products are newer foil or kraft-faced foam board products, there is no reason to apply a moisture sealer to them, and where foil was used, I doubt that it would adhere well anyway. If the boards are exposed in an occupied space, fire codes will require that a fire resistant finish surface such as drywall be installed.
Watch out: Keep insulating fiberboard dry during construction and protect it from wetting after installation.
During building construction, insulating fiberboard sheathing should be protected from water (rain, melting snow) on the jobsite during construction before it is applied to the structure itself. The US FPL found that
Soaking [fiberboard insulating sheathing] for 6 hours before test reduced the modulus of rupture and lateral nail resistance of the fiberboard to about 75 percent of the value for dry material.
The moisture content was about 16 percent. When the material was soaked for 48 hours before test, the modulus of rupture and lateral nail resistance were reduced to about 40 percent of the values for dry material, and the moisture content was about 45 percent. 
The results of tests of the several properties investigated indicated that all 14 [insulating fiber] boards meet the commercial standard. The reductions in strength caused by wetting indicate that the insulating fiberboards should be kept dry during erection.
Of even more importance is the necessity of keeping sheathing dry during service by the installation of good moisture barriers in those houses erected in parts of the country where moisture condensation is a problem.
Watch out: while fiberboard products, especially sealed or waxed products are rather resistant to mold growth, soaking the material can lead to mold contamination problems, as we illustrate at FIBERBOARD SHEATHING MOLD CONTAMINATION
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 Homasote® Company, 932 Lower Ferry Road, West Trenton, NJ 08628-0240 Tel: 800-257-9491 Ext 1332, or from outside the U.S. call 609-883-3300. Website: http://www.homasote.com/ , Email: Sales@homasote.com.
Thanks to Homasote CEO Warren Flicker for technical review and comment on this article.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: email@example.com
 Celotex Corporation, PO Box 31602, Tampa FL 33631, with offices in Atlanta, Chicago, Cincinnati, Dallas, Oakland and Philadelphia, and plants in six U.S. States is headquartered in Tampa, FL. Celotex is a national manufacturer of residential and commercial building materials. Website: www.celotex.com Tel: 800-CELOTEX
"Insulation Selector Guide", Celotex Corporation, web search 6/29/12, original source: http://www.silvercote.com/PDF/ThermaxInsulSelectorGuide.pdf, [copy on file as CelotexThermaxInsulSelectorGuide.pdf ]
"Celotex Blue Ridge Fiberboard", SturdyBrace®, produced by Blue Ridge Fiberboard Inc., 250 Celotex Dr., Danville VA 24541, product literature, web search 6/29/2012, original source: blueridgefiberboard.com/pages/sturdybrace.php, [Copy on file as Celotex_BlueRidge_SturdyBrace.pdf].
MSDS: original source: blueridgefiberboard.com/pages/sturdybrace/pdfs/SturdyBrace-msds-br.pdf
"Guide Specifications: SturdyBrace® Structural Fiberboard Wall Sheathing", 6/29/12, original source: blueridgefiberboard.com/pages/sturdybrace.php [Copy on file as SturdyBrace-guidespecs.pdf]
 Douglas Leen, Petersburg AK 99833, contributed the photograph of insulating board scraps from roof insulation removed from a building. Dr. Leen provides such a wide range of services, collectables, and historical information about the Northwest that a succinct description is difficult: flying dentist goes anywhere, antique forestry posters, historic campers, the tugboat Katahdin, in Alaska, Washington, and Wyoming. Mr. Leen can be contacted at firstname.lastname@example.org or at 907-518-0335
 Georgia Pacific: information about DensGlas gypsum board building sheathing can be found at the company's website at gp.com/build/product.aspx?pid=4674
 Pittsburgh Press, "Yesterday - in costly homes alone, Today even the simplest home can have this hidden comfort", The Pittsburgh Press, 19 April 1925, classified ads section. Web search 6/22/12, [Copy on file as Celotex_Ad_023_PP.jpg and more]
 pending research
Patents pertaining to building insulation & insulating board, Celotex & Insulating Board type products
"Sound absorbing board for walls and ceilings", Patent No. 1,554,180, issued to W.S. Trader, September 15,1925, first disclosed a wallboard constructed from "Celotex", a felted mass of strong bagasse fibers, so compacted as to be capable of use as an artificial lumber in that it can be sawed and nailed, and has sufficient strength in many cases to be substituted for lumber. That same patent mentions "Insulite", a building board made from wood pulp tailings and which likewise has a porous fibrous body portion and which is possessed of considerable strength so that the same can be nailed, etc. Celotex was preferred as an insulating material because its internal cells produce a sound-deadening insulating effect.
"Method and apparatus for drying moving material", Treadway B. Munroe et als, assigned to Dahlberg & Co., U.S. Patent No. 1,598,980, 7 September 1926, described a method and apparatus for drying sheets of artificial heat insulating lumber, known on the market as Celotex, improving the original process.
"Reenforced composition board", Treadway B. Munroe et als, U.S. Patent No. 1,578,344, 30 March 1926
"Insulating Structural Board", U.S. Patent 2,159,300, Armen H. Tashjian et als, assigned to William B. Miller, Lakewood OH, 23 May 1939, describes insulating structural boards of laminated construction for use as roof or floor slabs, and refers to "Standard insulating fiber boards, such as "Celotex", "Masonite", "Insulite", etc. that had excellent insulating properties but have relatively slight structural strength in flexure or bending under load, hence are not and cannot be used as structural slabs for load sustaining purposes, as roof or floor slabs, for example. [Adding structural strength ran into the problem of reducing the insulating value of the product.]
"Sound-absorbing chamber", Treadway B. Munroe et als, U.S. Patent No. 1,705,778, 19 March 1929 (using Celotex to construct a sound deadening chamber.
"Method of and apparatus for drying moving material", U.S. Patent 2,376,612, Carl G. Muench, New Orleans, assigned to Celotex Corporation, described a method and apparatus for drying sheets of artificial heat insulating lumber, preferably formed by the felting of bagasse fiber along with other materials necessary to make a satisfactory structural fiber board. 22 May 1945
"Sound-absorbing board for walls and ceilings," U.S. Patent 1,554,180, Sept. 15, 1925, Wilber S. Trader, assignor to Dahlberg & Company, Chicago IL. described an interior-use sound insulating product.
 "Insulite Co. v. Reserve Supply Co.," 60F.2d 433 (1932), Circuit Court of Appeals, Eighth Circuit, July 26, 1932. Web Search t/23/12. Quoting:
Rabbeted joints in material to which plaster or other material is applied are found in the Jones patent, No. 886,813. In this patent the composition is made up of plaster of paris, cement, or other like substance, combined with hair, wood fiber, sawdust, wool, wood shavings, excelsior, straw, or similar substances. The length of the lath covers three joists instead of four. The boards are arranged in staggered relation to each other and the joints are shiplapped. The specification states that after the boards or blocks are placed in position they may be covered with wallpaper or other similar material, which, of course, would include plaster.
"Machine for perforating Insulite Boards", U.S. Patent No. 1,306,283, Patented 10 June 1919, John K. Shaw, inventor from Minneapolis MN, describes improvements for machines for perforating Insulite Boards.
"Before you Build write for this mailing piece and a sample of Insulite", [advertisement], The Literary Digest, 13 September 1940.
 Museum of Fine Arts, Boston, web search 6/22/12, original source: http://cameo.mfa.org/browse/record.asp?subkey=3644 [Copy on file as MFAB_Fiberboard.pdf]
 "Separating the Fiber of Wood", A.S. Lyman, U.S. Patent No. 21,077, 3 August 1858
 Standards pertaining to fiberboard insulating sheathing:
ASTM C 208-95 (2001) – Standard Specification for Cellulosic Fiber Insulating Board. Type IV Grade 2 (Structural Wall Sheathing).
ASTM C 846-94 (2003) – Application of Cellulosic Fiber Insulating Board for Wall Sheathing.
ASTM D 1554 - Definitions of terms Relating to Wood Based Fiber and Particle Panel Materials.
ASTM E-72 (1997)- Standard Method for Conducting Strength Tests of Panels for Building Construction.
ANSI /AHA - A194.1, Cellulosic Fiberboard.
U.S. Department of Commerce: PS57-73, Cellulosic Fiber Insulating Board
A.F.A. (2003): Fiberboard Sheathing test results
 "Properties of insulating fiberboard sheathing",
Forest Products Laboratory (U.S.)
Luxford, R. F. (Ronald Floyd), 1889 (1960), original report 1955, citation:hdl.handle.net/1957/2489, web search 6/29/12, original source: http://ir.library.oregonstate.edu/xmlui/handle/1957/2489
Design of Wood Structures - ASD, Donald E. Breyer, Kenneth Fridley, Kelly Cobeen, David Pollock, McGraw Hill, 2003, ISBN-10: 0071379320, ISBN-13: 978-0071379328
This book is an update of a long-established text dating from at least 1988 (DJF); Quoting: This book is gives a good grasp of seismic design for wood structures. Many of the examples especially near the end are good practice for the California PE Special Seismic Exam design questions. It gives a good grasp of how seismic forces move through a building and how to calculate those forces at various locations.THE CLASSIC TEXT ON WOOD DESIGN UPDATED TO INCLUDE THE LATEST CODES AND DATA. Reflects the most recent provisions of the 2003 International Building Code and 2001 National Design Specification for Wood Construction. Continuing the sterling standard set by earlier editions, this indispensable reference clearly explains the best wood design techniques for the safe handling of gravity and lateral loads. Carefully revised and updated to include the new 2003 International Building Code, ASCE 7-02 Minimum Design Loads for Buildings and Other Structures, the 2001 National Design Specification for Wood Construction, and the most recent Allowable Stress Design.
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting: A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. 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.
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