Mold proof drywall ? You Must Be Kidding! InteriorAPedia © Is the new "mold resistant drywall" a viable product? Using mold-resistant or "mold proof" drywall or gypsum board products as a step in preventing mold growth in buildings - advice Drywall and gypsum board standards, trade practices, & MSDS Sheets Imported drywall from China or other countries: product quality & health concerns?

This article reviews the benefits and limitations of using "mold resistant" drywall, gypsum board, or "Sheetrock^(TM)" (which is a trademark) as a step in building mold-resistant construction. We include a list of drywall standards and MSDS information. While mold-resistant drywall may be a good idea for some problem-prone building locations, avoiding mold growth in buildings requires more than just this product. Below we raise a concern about the probable effectiveness of "mold resistant drywall" in large part because a careful reading of the manufacturer's data places very constrained limits on how this new and more expensive drywall is promised to perform. Also see SAMPLING DRYWALL for a discussion of mold on drywall. Moisture Gradients and Mold discusses the variation in type of mold growth found on drywall or gypsum board at different heights above a wet floor.

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Both of the major drywall companies are now marketing drywall which is advertised as offering "mold and mildew resistance". I was excited to hear about this because drywall in buildings, when it has gotten wet or been subjected to prolonged high moisture, is a very common place for mold growth. We find problem-mold both on the visible or room-side and often on the hidden or wall-cavity side of drywall.

What are you getting if you buy the new "mold resistant" gypsum panels to use after your mold remediation project?

First, Possibly Gouged: at a central New York mold remediation project the contractor told me that his local supplier was charging him four to eight times the cost of "regular" drywall (which he calls "sheetrock" (a trademarked name) or "gyp board" which is slang for gypsum panels.

Second, Promised very little: if the USG submittal sheet for "Sheetrock^(R)" Brand Humitek^(TM) Gypsum panels is any indicator, the manufacturer has given themselves an impressive escape clause. Quoting from the product limitations on this USG document, using its item numbers:

1. Avoid exposure to temperatures exceeding 125 deg F (Translation: keep it away from your boiler flue, it's not fire-rated).
2. Avoid exposure to excessive or continuous moisture before, during and after installation. Eliminate sources of moisture immediately. (Translation: if you put this material in an environment where mold grew on your old drywall, we're not promising that this product will perform any better.)
3. Not suitable for use in high moisture areas such as tub and shower enclosures, gang showers, and other areas subject to direct water exposure. (Translation: you shouldn't have used your old drywall in the bathroom and you shouldn't put this new product near the tub, sink, or shower.)
4. Non load bearing.

The moisture and mold resistance of this material is cited as "Per ASTM C473, the average water absorption for panels is not greater than 5 percent by weight after two-hour immersion." (Translation: sounds great, doesn't it?)

Use mold resistant gypsum panels with hesitation and caution

This product sounds like a great idea but ... considering the limitations stated by the manufacturer, I would want to see a lot more about the make-up, testing, and field-use experience of this material before I'd pay the premium suppliers are getting to provide it to your mold remediation contractor.

Anyone who has used moldproof drywall and sees what they think is mold growing on this new product is welcome to send a sample to my lab.

If your sample comes from Humitek™ or any other drywall manufacturer who provides mold-resistant drywall, we will process your sample pro-bono. See inspect-ny.com/sickhouse/bulksamp.htm for easy to follow mold sampling procedures and mailing instructions.

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INTERIORS of BUILDINGS
ASBESTOS - Containing Materials & Hazards
ENVIRONMENTAL HAZARDS
FIBERGLASS INSULATION
MOLD RESISTANT DRYWALL
MOLD PREVENTION
MOLD INFORMATION CENTER
MOLDY CARPETS
MVOCs & MOLDY MUSTY ODORS
ODORS & SMELLS DIAGNOSIS & CURE
PAINT FAILURES
ROT, FUNGUS, TERMITES
ROT, TIMBER FRAME
STAIN DIAGNOSIS
THERMAL TRACKING
WATER ENTRY in BUILDINGS
WINTERIZE A BUILDING

Drywall Installation & Product Standards

• Association of the Wall & Ceiling Industry - awci.org "AWCI represents 2,200 companies and organizations in the acoustics systems, ceiling systems, drywall systems, exterior insulation and finishing systems, fireproofing, flooring systems, insulation, and stucco contractors, suppliers and manufacturers and those in allied trades.  Our mission is to provide services and undertake activities that enhance the members' ability to operate a successful business."
• Drywall Finishing Council "is a Not For Profit, Mutual Benefit Organization that seeks to represent the issues that are commonly faced by manufacturers of materials used in the finishing of drywall" - see dwfc.org and see this .PDF about the Drywall Finishing Council. The DFC website provides additional documents: "a visual evaluation method for inspecting joint treated gypsum panel surfaces", "Interior Job Condition Specifications For The Application Of Drywall Joint Compounds, Drywall Textures, And Paints/Coatings", and "guidelines for determining the visual performance expectations of a Level 5 finish" drywall systems.
• Drywall Grid System Standards:
  • ASTM C635 Standard Specification for the Manufacture, Performance, and Testing of Metal Suspension Systems for Acoustical Tile and Lay-in Panel Ceilings
  • ASTM C636 Standard Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-in Panels
  • ASTM C645 Standard Specification for Nonstructural Steel Framing Members
  • ASTM C754 Standard Specification for Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products
  • CISCA Ceiling & Interior Systems Construction Association
  • DSA PA105 Division of the State Architect (California)
  • IBC International Building Code
  • ICC ESR-1289 International Code Council Evaluation Service
  • NOA 04-0716.03 Dade/Broward County, Florida Product Approval
  • RR25348 City of Los Angeles Research Report
  • UBC 25-2 Uniform Building Code Standard (section 25.210, exception 2)
  • UL Underwriters Laboratories Inc. Fire Resistance Directory
  • Also see the Armstrong Corporation's article on drywall grid system installation details at armstrong.com/common/c2002/content/files/4279.pdf or contact the company at 877-ARM-STRONG
• Gypsum Association, www.gypsum.org - 810 First St. N.E. Suite 510, Washington D.C. 20002, 202-289-4550. A gypsum drywall trade association that includes the following corporations: American Gypsum logo, CertainTeed Gypsum, Inc., CertainTeed Gypsum Canada Inc., CGC Inc., Federal Gypsum Company, Georgia-Pacific Gypsum, Lafarge North America, National Gypsum Co., PABCO Gypsum, Temple-Inland, United States Gypsum. (Most of these companies also publish product installation and specifications guides.)
  
  The Gypsum Association association provides quite a few online documents addressing the installation and assessment of gypsum board products, including
  • Gypsum Board Evaluation Report - ES Report ESR-1338, 12/1/2007, Division 09, Gypsum Board Assemblies, prepared by ICC Evaluation Service, Inc. (icc-es.org) provides an independent evaluation of contemorary drywall or gypsum board products with respect to building code compliance (2006 International Building Code IBC and the 2006 International Residential Code IRC) with respect to interior finish, fire resistance, sound control, structural considerations, thermal barrier, and exterior finish.
  • Assessing Water Damage to Gypsum Board - (GA-231-06), "general industry conditions for assessing gypsum board that has been exposed to water or elevated levels of moisture. Includes recommendations for drying conditions" - available for purchase in hard copy form at www.gypsum.org
  • "Recommended Levels of Gypsum Board Finish", available at www.gypsum.org
  • Fire Resistance Design Manual GA-600, The 18th edition includes fire-resistance ratings for over 370 gypsum-protected wall, ceiling, roof, column, beam, girder, and truss systems. available for purchase in hard copy form at www.gypsum.org
  • Recommended Levels of Gypsum Board Finish (GA-214-07), "jointly produced by the four leading associations in the industry, assists specifiers, owners, and contractors to precisely describe the desired finish of individual walls and ceilings to meet specific needs. Avoids non-specific terms like "industry standards" and "workmanlike finish" and the problems they can cause" available for purchase in hard copy form at www.gypsum.org
  • Reparing Screw or Nail Pops [in drywall or gypsum board] (GA-222-08), "the symptoms, causes, and repair methods for fastener pops in gypsum board surfaces." available for purchase in hard copy form at www.gypsum.org
• Massachusetts Design & Construction Guidelines & Standards for Gypsum Drywall - 09 20 00
• MSDS data for various drywall products
  • FIBEROCK® Brand Gypsum Fiber Underlayment - (US Gypsum) MSDS
  • FIBEROCK® Brand Abuse-Resistant Gypsum Fiber Panels (US Gypsum) MSDS
  • FIBEROCK® Brand Gypsum Fiber Sheathing Panels (US Gypsum) MSDS
  • Fiberock® Brand Aqua-Tough™Interior Panels (US Gypsum) MSDS
  • Hamilton drywall products Sher-Tex® PremiumMSDS
  • Plaster - sample (US Gypsum) MSDS
  • SHEETROCK® Brand Gypsum Panels (US Gypsum) MSDS
  • SHEETROCK® Brand HUMITEK™ Gypsum Liner Panels (US Gypsum) MSDS
  • Additional pertinent product MSDS from US Gypsum are at www.cgcinc.com/home.asp?nav=38&mkt=30&bc=1.18.38

• Thanks to Jamie S. for detailed link editing assistance 4/11/2009
  

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