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Mold Growth on Fiberboard Building Sheathing & Insulating Board Sheathing Products in Flooded Homes InspectAPedia®  -          How much insulating board should be removed from a home after flooding? Does insulating board or fiberboard support mold growth? How to recognize Celotex®, Homasote®, Masonite® and other insulating board building sheathing products Repairing or replacing "blackboard" fiber insulating board on homes Questions & answers about mold on fiberboard building products

Fiberboard mold: this article discusses flood damage and mold damage on fiberboard insulating products and building sheathing products such as Homasote, Celotex, and Masonite insulating board sheathing.

Readers should see Sheathing Homasote & Other Board for help in identifying types of building sheathing boards. Also see Sheathing, Gypsum board, and SHEATHING, OSB as well as Sheathing, Plywood for a discussion of these common building roof and wall sheathing products.

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Mold Growth & Wood Boring Insect Susceptibility of Fiberboard Building Insulating Sheathing Products

We do not usually find mold growth on fiberboard building insulating sheathing nor insect damage to this material. Possibly the resin binder and coating is unattractive to insects and the moisture resistance of some coatings also reduce the ease of mold growth on this material.

However in sufficiently challenging conditions such as very wet conditions or prolonged exposure to water and moisture or insects, we have found both extensive mold growth on Homasote type insulating board (photo, left, in a wet basement against a masonry wall) and evidence of insect damage to an interior wall fiberboard sheathing product, probably Beaver board or Upson board (in the attic of a leaky building, below right).

At Plaster & Beaverboard & Drywall we provide the history of Beaver board and Upson board, and we discuss other non-structural interior sheathing boards that were used on building interior walls and ceilings.

Question About Mold on Celotex Building Insulating Board Following Hurricane-Caused Flooding

Question:

We are survivors (not victims) of the Tennessee flood that came on May 1st 2010. Water was in our home for 34 hours including the 1st level (basement) and 3 feet on the main level.

We have taken everything out of the building, removing interior materials down to the studs (walls) and joists (ceilings and floors). Our Insurance is ready to make their first offer, They asked about the sheathing saying if it was chip board it would need to be removed. Or plywood should be OK if ventilated correctly. Well, it's nether, occurring to your website it's Celotex™, the back is smooth while the inside is fibrous. I cut a chunk out and it's wet. Should that come out? I say yes. The home was built. 1970s

How do you replace wet fiberboard insulation? Remove outside brick? Remove the stud walls. Surely not!

Also FEMA says the basement is the 1st level of the home, because it has a door to enter & exit to the outside. Insurance saying it's a basement. (which covers nothing). If you are unable to do this Pro-Bono, we understand, and we thank you for your web site. - T.

Answer:

OPINION: Since we have certainly seen that Celotex and other fiberboard insulation products can sometimes support mold growth, the wet insulating board should be removed. A photograph of moldy insulating board in a flooded home is shown in our photo at left and as discussed also at Mold Growth & Wood Boring Insect Susceptibility of Fiberboard Building Insulating Sheathing. (Also see INSULATION MOLD where we describe non-visible but significant mold contamination found in fiberglass insulation that has been wet or exposed to high moisture or high mold levels.)

Watch Out: In this case someone recognizing the great cost of redoing the brick veneer may want to try installing a very very secure barrier between the celotex and building interior - it might work but this questionable approach risks leaving a mold problem in place - something that could later be a problem for building occupants, especially people at extra risk such as asthmatics, elderly, infants, immune people.

Watch Out: Leaving wet insulating board in place and then re-building over it creates a very high risk of later hidden mold in building walls and ceilings. It is tricky to decide that the insulating board is really dry throughout as its dryout can take weeks, even months where the insulation is covered by a brick exterior wall, by contacting wood framing, or by other materials.

Watch Out: The right hand photo shown above tells us that interior drywall or plaster were removed only for the first four feet of the flooded wall. This is about 12" above the high water level in the building. There is a good chance that water wicked higher into building materials including the drywall, insulation, and fiberboard insulation in these walls. Leaving wet, possibly moldy insulation in place also leaves a future property resale difficulty as the home may be "stigmatized" as not having been thoroughly cleaned and repaired following a major flood.

How is Wet Insulating Board Removed Where a Masonry Veneer is Installed Outside?

Unfortunately to completely remove the wet insulating board from this building will be a costly and destructive task. You probably don't have the option of "removing the studs from inside" since the brick veneer is typically tied to and thus supported by the wood framing.

The contractor and other parties involved as well as local building officials need to agree on a safe procedure for the particular structure involved. But here are some general comments about how insulating board is removed from a building where an exterior veneer of brick or stone are installed.

A temporary support wall is constructed inside the building parallel to the wall where the insulating board must be removed. The support wall involves a top header, support posts, and often a sill plate that distributes its load safely across the floor below or down to a basement slab or footings.

We have repaired a brick veneer building from the inside (for example in a non-flood case of extreme termite damage) by working carefully on the interior side of the veneer wall, in small sections so that there was not a risk of wall collapse.

We removed and replaced damaged wallboard, insulation, and studs. New studs and sill and top plates were installed and metal ties were reconnected to the studs to continue to secure the brick veneer wall. It was technically not difficult, but it was a labor intensive procedure.

The temporary support wall allows the contractor to remove sections of exterior wall studs (and the insulating board between the wall studs and the exterior masonry veneer) without risking the ceiling above collapsing. The support wall is spaced far enough in from the original exterior wall to give access to the original studs and wall, but close enough to the outside wall to safely support the floor above - often just a couple of feet. The support wall is usually constructed using a heavy beam or header rather than a simple flat 2x4 top plate. The beam allows the temporary wall's supporting posts to be placed 4 feet or more apart, giving plenty of working space.

How Much Insulating Board to Remove?

You might know better just how much of the insulating board needed to be replaced above whatever has been soaked if you have a very thorough inspection and testing for mold, including test cuts to check the hidden side of the insulating board (such as Celotex™ material) in the most-suspect locations where moisture may have been present.

Where Does Mold Occur on Insulating Board?

Where we have found insulating board products such as Homasote or Celotex to be moldy, it has been in areas of flooding that wet the board.

If none of the dry, un-damaged insulating board is found to be moldy, where it is left in place, the seal up approach or use of a fungicidal sealant on dry surfaces might be fine. If you can you send us photos of the home inside and out we may be able to comment further on where to look for hidden problems. But the best approach is to bring in an experienced inspector who knows where to look and how to test building materials for wetness, dampness, or mold.

What Are the Structural Differences Between Chipboard, OSB, and Insulating Board?

You won't find "chipboard" used as building sheathing. "Chipboard" is compressed sawdust-like material, often used for shelving. But you might find oriented strand-board or OSB sheathing in place, depending on when your home was built. That is probably what your insurance company meant by "chipboard" sheathing. Ask your Insurance company if their issue with OSB sheathing that has been soaked is a structural concern or a mold concern.

Insulating board products such as Celotex™ or Homasote™ are not structural. Where those products were used as wall sheathing you'll typically find either diagonal wood or metal bracing at the building corners, or structural plywood used in those locations.

Bottom Line: Don't Leave Wet or Moldy Materials In Place After Building Flooding

But in any case don't leave a mold reservoir in place in a building following flooding. Doing so simply risks having to do the whole job over again later.

Bottom line, we expect that in your case, since you described soaking wet insulating board materials, the Celotex™ needs to come out because of the mold concern. Any attempt to reconstruct the building while leaving soaking wet material in place will very likely produce a new wall or ceiling cavity mold problem and the whole job would end up needing to be done again.

Finally, your insurance company may define the lowest floor of your home as "basement" in order to reduce their loss coverage expense. But if the lowest floor opens to grade on at least one side, and was finished as living space, especially supported by FEMA's own description, you may be able to satisfy your insurance company that this was code-approved living space not "basement" (a non-living space area).

There are no fees to consult with us regarding natural disasters such as area flooding.

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INSULATION MOLD
  Mold in Fiberglass Insulation
  Mold on Books, Book Conservation
  Mold on Fiberboard Insulating Sheathing
  MOLD PREVENTION AFTER FLOODING
  MOLD RESISTANT CONSTRUCTION
  Mold in Foam Insulation
  Moldy insulation may look clean
  Why does mold grow in fiberglass?
  When to test insulation for mold
  How to Test for Mold in Insulation
  References, Fiberglass Hazards
  Vacuuming exposed insulation

• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• Repairing Your Flooded Home American Red Cross and FEMA - PDF - English
• Como Reparar su Hogar Inundado American Red Cross and FEMA - PDF - espanol
• Flood Cleanup - Avoiding Indoor Air Quality Problems US EPA Fact Sheet
• Cleaning Up After a Flood Texas Department of State Health Services
• Celotex Corporation, headquartered in Tampa, FL, is a national manufacturer of residential and commercial building materials. www.celotex.com 800-CELOTEX
  
• 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 mail@dougleen.com or at 907-518-0335
• America's Favorite Homes, mail-order catalogues as a guide to popular early 20th-century houses, Robert Schweitzer, Michael W.R. Davis, 1990, Wayne State University Press ISBN 0814320066 (may be available from Wayne State University Press)
• American Plywood Association, APA, "Portland Manufacturing Company, No. 1, a series of monographs on the history of plywood manufacturing",Plywood Pioneers Association, 31 March, 1967, apawood.org 253-620-7400 APAWood.org
• 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
• Homasote Co., 932 Lower Ferry Road, West Trenton, New Jersey 08628-024, U.S.A. 800-257-9491 homasote.com
• "Hurricane Damage to Residential Structures: Risk and Mitigation", Jon K. Ayscue, The Johns Hopkins University, Baltimore, Maryland, published by the Natural Hazards Research and Applications Information Center, Institute of Behavioral Science, University of Colorado, November 1996. Abstract:
  "Property damage and loss from hurricanes have increased with population growth in coastal areas, and climatic factors point to more frequent and intense hurricanes in the future. This paper describes potential hurricane hazards from wind and water. Damage to residential structures from three recent intense hurricanes - Hugo, Andrew, and Iniki - shows that wind is responsible for greater property loss than water. The current state-of-the-art building technology is sufficient to reduce damage from hurricanes when properly applied, and this paper discusses those building techniques that can mitigate hurricane damage and recommends measures for mitigating future hurricane damage to homes." - online at www.colorado.edu/hazards/publications/wp/wp94/wp94.html
• Thanks to reader Tammy X for discussing concerns about and procedures for removing fiberboard insulation from a flooded home in Tennessed 27 May 2010.
• Thermafiber, Inc., 3711 Mill Street, Wabash, IN 46992, 260-563-2111 www.thermafiber.com
• Weaver: Beaver Board and Upson Board: Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver, APT Bulletin, Vol. 28, No. 2/3 (1997), pp. 71-78, Association for Preservation Technology International (APT), available online at JSTOR.

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.
• Environmental Health & Investigation Bibliography - our technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
• Adkins and Adkins Dictionary of Roman Religion discusses Robigus, the Roman god of crop protection and the legendary progenitor of wheat rust fungus.
• Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
• "A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
• US EPA - Mold Remediation in Schools and Commercial Building [ copy on file as /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
• US EPA - Una Breva Guia a Moho - Hongo [on file as /sickhouse/EPA_Moho_Guia_sp.pdf - - en Espanol

Mold Contamination Testing, Cleanup, Prevention: references & products

• The Mold Information Center: What to Do About Mold in buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
• Aerobiology, Building Science, Microscopy, & Laboratory References, an extensive technical bibliography
• Allergens: what they look like in buildings
• Associations: Sick House, Sick Building, SBS - Air Quality, Government, Private Associations and Information Resources
• Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon)
• Atlas of Mold Related Illness: Index of Symptoms and health, physical, neurological, psychological, and other complaint which people suspect may be mold or building-related.
• Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
• Black Mold that is Harmless Photos of recognizable, usually harmless black mold on wood, bluestain, ceratocystis, ophistoma
• Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
• Classes of Mold: what types of cosmetic, allergenic, or toxic mold are a problem? Can mold be cleaned-up successfully?
• Clinical Mold References - Detailed bibliography of mold reference texts
• "A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
• "Disease Prevention Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
• "Disease Prevention in Home Vegetable Gardens," Patricia Donald, Department of Plant Microbiology and Pathology, Lewis Jett
  Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
• "Management of Powdery Mildew, Leveillula taurica, in Greenhouse Peppers," Ministry of Agriculture and Lands, British Columbia - Original source: www.agf.gov.bc.ca/cropprot/peppermildew.htm
• Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
• Fiberglass: Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
• Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
• Fungi, Identifying Filamentous, A Clinical Laboratory Handbook, Guy St-Germain, Richard Summerbell, Star Publishing, 1996, ISBN 0-89863-177-7 (English) (buy at Amazon)
• Looking for Mold Procedure: what mold is often found where in buildings - simple technical presentation
• Meruliporia: the house eating fungus or "poria"
• Mold Action Guide: Step-by-Step Instructions, What to do about mold, mildew, and other indoor allergens
• MOLD APPEARANCE - WHAT MOLD LOOKS LIKE Photos of what mold looks like in buildings
• MOLD APPEARANCE - STUFF THAT IS NOT MOLD Photos of NOT-mold material that is sometimes mistaken for mold
• MOLD ATLAS & PARTICLES INDEX, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
• MOLD BY MICROSCOPE Mold under the microscope - photo identification of the most common indoor molds found in buildings
• Mold FAQs Answers to Most Questions about Indoor Mold, Mold Related Illness, Mold Cleanup, Mold Prevention
• US EPA: Mold Remediation in Schools and Commercial Building [ copy on file as /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
• Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens
• Mold Test Kits - How to Collect and Send Your Own Mold Sample to our mold testing lab or to any mold lab you wish
• Most Common Indoor Molds Found in buildings, A Table of
• Mycology, Fundamentals of Diagnostic, Fran Fisher, Norma B. Cook, W.B. Saunders Co. 1998, ISBN 0-7216-5006-6 (buy this book at Amazon)
• Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
• Rot concerns in buildings-some building mold such as Meruliporia incrassata "Poria" risks serious rot and hidden structural damage
• US EPA: Una Breva Guia a Moho - Hongo [on file as /sickhouse/EPA_Moho_Guia_sp.pdf - - en Espanol

OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold

Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.

• Fiberglass building insulation and HVAC duct work insulation hazards
• Sewage and Septic backup contamination in buildings: inspection, testing, remediation, & references to expert sources
• Other environmental risks: Asbestos, carbon monoxide, electromagnetic fields, environmental illness, fiberglass, MCS - multiple chemical sensitivity, toxic gases, etc
• Indoor Gas Sampling Plan for Residential buildings lists a number of toxic indoor gases which we test for, depending on the building complaint and building conditions
• Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
• Pet control - if you can't say goodbye to your bird, cat, dog, guinea pig, hamster, tropical fish, then limit the areas they occupy and limit the airflow from that area to sleeping or other areas of the building, use allergenic bedding, eliminate wall-to-wall carpeting, improve housecleaning including use of a HEPA-rated vacuum cleaner. For more details see our article Dog, Cat, and Other Animal Dander - Information for Asthmatics and Indoor Air Quality
• Rodents, Mice, Squirrel Control - I find high levels of mouse and rodent dander, fecal dust, and urine-contaminated dust in some buildings, and high levels of these materials in building insulation in those locations. If you have a mouse problem, particularly if mice and their waste (fecals or urine) are contaminating the building HVAC or building insulation, may need both steps to clean up or remove infected materials and steps to stop an ongoing rodent problem. If squirrels are a problem, the cleanup needs to include closing off entry openings into the building. Get some help from a licensed pest control expert.
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