MOISTURE & MOLD In Construction

OUTLINE Review Solutions Resources Here is our agenda: Mold Review What is mold How can it be controlled How is it impacting our industry What has caused the increased attention to this issue Potential Solutions What are some potential solutions We’ll discuss some of USG’s solutions – solutions that can make a positive impact on a project and your reputation without negatively impacting productivity USG Resources What resources are available to help you and your teams learn more about this issue AND explain the mold issue to your customers.

Can be benign, beneficial or harmful WHAT IS MOLD? Molds are fungi Living micro-organisms Neither plant nor animal Separate kingdom in biology Found everywhere Over 100,000 known species Can be benign, beneficial or harmful Essential part of our natural environment Feed on nutrients present in most organic fibers Vital decay & recycling mechanism Lets begin with answering, “What is mold?” Molds are fungi. These naturally occurring living organisms are found everywhere and make up roughly 25% of the earth’s biomass. Like plants and animals, fungi occupy their own separate kingdom in the world of biology. Over millions of years, fungi have evolved in tremendous diversity occupying almost every environmental niche. More than 100,000 species of molds have been identified and it is estimated that there may be as many as 1.4 million species in the world. We coexist with molds everywhere. Some molds are benign to humans. In fact, many are beneficial to us, providing food, medicine and other desirable products. The first antibiotic, penicillin, is named for the mold from which it is derived. There would be no leavened bread, cheese, wine or beer without mold. A few species are harmful to humans, although they too are important to us in various ways. In short, molds are an essential part of our environment. They grow on a food source, breaking it down chemically to absorb nutrients they need to grow. As such, molds play a critically important role in the decomposition and recycling of nutrient/food sources in the biosphere.

CONDITIONS FOR MOLD GROWTH Temperature: 40 – 95 °F = ideal range Found everywhere! Over 100 varieties grow in buildings Need “clean room” environment to control Spores Food sources which are found in most building materials Found in dust from construction and normal use Nutrients Must be liquid moisture! Roof leaks Pipe leaks Windows Condensation Wet construction Moisture What conditions result in mold development and growth? Mold growth is temperature sensitive. Molds can grow over a broad range of temperatures, but the species most commonly found in buildings find 40 – 95 oF to be ideal with the most copious growth occurring around 70 – 90 oF. Human comfort prevents us from being able to use temperature to control mold growth to any appreciable degree. If the building is comfortable to us, it will provide an ideal temperature for mold growth. Therefore, temperature cannot be used to prevent or control mold in buildings. When considering the factors necessary for mold growth, three other essential components must be present: First, you must have mold spores. These are the microscopic “seeds” from which mold germinates and grows. This requirement is easily met. Spores are found in abundance everywhere in our environment, indoors and outdoors, in the air and on the surfaces. You inhale spores with every breath you take, they are on every exposed surface. There are over 100 species of mold common to buildings. Eliminating mold spores requires rigorous “clean room” conditions. This can be done at great expense and effort for certain highly specialized manufacturing or medical facilities, but it is impossible to do with buildings in general. The next critical ingredient is nutrients. Molds feed on most organic materials, taking in carbon and other nutrients to build their internal cell structure. The necessary nutrients are found in most building materials – cellulose in paper and wood, polymeric plastics, etc. Name just about any building material and there is a mold that is capable of excreting enzymes that dissolve and digest the nutrients in it. If not, then dust and dirt on the surface will provide sufficient nutrients for a hardy pioneer species to get started allowing other opportunistic species to take hold after that, feeding on both the initial mold growth as well as the chemically altered surface of the substrate. Chemical fungicides can be used to remove nutrients from the food chain by rendering them toxic or unavailable to mold, but molds are remarkably adaptable and any chemical that is harmful to molds is potentially harmful to humans. This option must be exercised judiciously with great care. The third and final ingredient required for mold growth is moisture. There are many sources of moisture in buildings from exterior envelope leaks and plumbing leaks to condensation on cool surfaces and moisture from wet construction processes. There has been considerable debate about how much moisture is required for mold growth to occur. For mold spores to germinate, they must contact LIQUID water. Once growth has started, however, molds can extract moisture from humid air and their own metabolism to continue growing. A relative humidity of 80% is generally cited as the critical moisture level for initiating mold growth. While high humidity alone will not initiate growth on a dry surface, when the air in a room is 80% RH or higher it is likely that localized condensation will occur on cold spots around air conditioning vents or in stagnant air in closets where mold can get started. Once growth has begun, it will continue to flourish as long as the RH remains at 80% or higher.  

ELIMINATING MOLD GROWTH Requires a clean room environment to eliminate Impossible to eliminate in general construction Eliminate Spores All materials in the system must eliminate food sources or be treated with broad- spectrum fungicides Dust & construction waste must be removed prior to closing up systems Remove Nutrients Good design & construction practices can manage water sources & system drying potentials Water “events” must be immediately addressed Control Moisture As noted, spores can be found everywhere in our environment and are virtually impossible to control or eliminate. Therefore, we need to look elsewhere for developing a practical mold control strategy. Eliminating nutrients is not a viable long term strategy, either. Although inorganic building materials may provide some degree of robustness, it is not enough to simply remove nutrients from the building materials themselves. The environment must be cleansed of nutrients to prevent airborne dusts from contaminating surfaces. This simply is not feasible. Another means of eliminating nutrients is to poison or otherwise make them unavailable as food. This can be done with chemical fungicides, but with so many varieties of mold that can inhabit a structure a broad-spectrum fungicide package is needed or it will not be effective. This course must be followed very carefully and judiciously as any chemical that is harmful to mold is potential dangerous for human exposure. By far, the most practical & effective mold control strategy is to limit the availability of excess moisture. As you will find in various sources from the US EPA to “building science” literature, mold control is a moisture control issue. As with spores and nutrients, water is an unavoidable & important part of our environment. However, it can be managed through proper design and construction practices. Proper building operation & timely maintenance are also key to insuring that water events such as a roof or plumbing leak are promptly found & remediated before mold & moisture damage can occur.

Buildings have become more weather tight WHAT HAS CHANGED? Buildings have become more weather tight New materials & architectural design features Fast track construction Maintenance is a continuous lifetime concern Many people ask if we are seeing more mold in buildings than in the past and if that is a factor we need to consider. Opinions differ on this matter but, in general, the biggest change has been a heightened sensitivity to the issue that has resulted in lower tolerance for mold. Previously, people just cleaned it up and went on with their lives. Now, they’re concerned about potential health problems and they don’t tolerate mold anytime or anywhere. The majority of moisture problems still originate with water leaks – poor roofing or exterior flashing details, plumbing leaks, poor site drainage around the foundation, etc. These things haven’t changed from past practice. However, several significant changes have occurred in the construction industry over the past several decades that have contributed in varying degrees to making buildings more sensitive to moisture intrusion. These include: Buildings have become more weathertight and energy efficient. With less air leakage there is also a reduced drying potential for many climates. There is less opportunity for moisture to dry out of the structure once it becomes wet. We are working with an array of new building materials & architectural design features. Many traditional construction materials have given way to new materials that are lower cost or help conserve scarce resources. Although they look the same, many of these new materials have very different moisture characteristics than the materials they replaced. In addition, mechanical air conditioning has made it possible to transplant regional architectural styles to different climates & create entirely new design motifs. Design details that work well for New England may be inappropriate in a Gulf Coast climate & vice-versa. Mechanical control of indoor conditions allows the designer to isolate himself from climate considerations. Architects & designers must consider functional aspects of details, not just regard them as aesthetic features, and make sure that functionality is not lost. Fast track construction practices have elevated project management from an art to a science, but pushing costs & schedules to the limit can impact performance & durability. Projects must have adequate job site supervision to insure that as-built construction follows the design specifications and that moisture sensitive materials are stocked, stored & handled so that they are not be exposed to inclement weather, poor drying conditions or misuse. We also need to recognize that maintenance is a continuous lifetime concern. This common sense maxim has been devalued by current home ownership and real estate investment practices which are characterized by short term ownership patterns. This undermines the value of long term maintenance by continually shifting the near term burden to the next owner. Eventually, some unlucky owner is burdened with a very difficult & expensive problem that cannot be superficially hidden.

TESTING FOR MOLD GROWTH Commonly used mold growth test methods are for interior coatings & plastics, not sheet product building material Current test standards focus on individual products, not systems testing There are no established permissible exposure level (PEL) limits Air sampling & tape tests unnecessary If you see or smell mold, fix the problem! There is a need for system and product testing standards that will provide a more accurate view of actual performance in buildings.         The two most commonly used test protocols, ASTM D 3273 and ASTM G 21, were not developed for bulk panel building materials such as sheathings or ceiling tiles. One is a test protocol for paints and interior coatings while the other is for plastics with relatively low permeability and absorption rates. These test standards examine products under artificially created, static conditions. Building systems experience a extremely dynamic conditions where steady-state conditions are rarely if ever achieved. A new series of test protocols is needed that permits a more realistic assessment of product and system performance under conditions representative of actual building installations. Finally, although the business of measuring spore counts is booming, we do not have permissible exposure levels (PELs) to compare against. In essence, thousands of dollars are being spent collecting useless or unnecessary data. With funding from NSF, CDC, EPA and other government agencies, the medical research community has initiated an extensive research effort investigating the health effects of mold exposure, but the scientists agree that it will be many years before this research will be completed. In the meantime, there is no standard for interpreting the plethora of mold data being collected. In general, if mold is found then it should be remediated and the moisture source eliminated. It doesn’t matter what kind or how much mold, if you see it or smell it, the moisture problem must be fixed and the mold eliminated.  

A MOISTURE CONTROL ISSUE The only controllable factor linked to mold growth is moisture Virtually any building material can be negatively impacted by mold if proper moisture management practices are not followed Mold is a moisture control issue that must be managed by proper building design, construction, and maintenance practices There are no “silver bullets” to solve the mold issue The most important message we can leave you with is, “Mold is a Moisture Control Issue.” Although moisture is a common part of our environment, it is the only factor linked to mold growth that can universally be safely and effectively controlled. Virtually any building material can harbor mold growth if proper moisture management practices. Unless potentially toxic compounds are added, even inorganic materials provide can collect dust and spores on their surfaces and in the crevices of their textures that will allow mold to flourish under the right conditions. Because water is so prevalent in all aspects of our lives, moisture control requires a moisture management strategy based on proper building design, construction and maintenance practices. Everyone wants quick and easy fixes to their problems. Billions are spent every year on quack dietary supplements that promise effortless weight loss and body toning. We know this is impossible, but we still purchase them in the hopes that each will provide the desired solution. It just seems easier than establishing and maintaining a healthy diet and exercise regimen. The issue of mold and moisture control in buildings is no different. We want products that will simply make the problem go away, but there are no “silver bullets” that will solve the mold issue. Every quick, simplistic solution is accompanied by its own unique set of unintended consequences. Dodging the issue and finger pointing won’t help, either, because we are dealing with a chain of causalities. Break any link of that chain and you’re headed for a problem. We simply must begin designing, constructing and operating buildings to respect the laws of physics and biology.  

MOISTURE EXPOSURE IN BUILDINGS Construction First year Remaining life Key drivers Weather Wet construction processes Site preparation & drainage Job scheduling & logistics Materials transport & storage Dry out period for wet building materials Poor construction Occupancy & lifestyle factors Poor design (e.g., condensation, leaks) Catastrophic events Occupancy & lifestyle factors Intrinsic moisture sources Wet construction processes Concrete & masonry Poured flooring Interior finishing Wet construction processes Concrete & Masonry Structural framing lumber Wet areas Wet areas Bathrooms Kitchens Indoor pools & locker rooms To adequately understand & develop moisture control strategies, a building’s life needs to be viewed in three critical stages: 1. Initial construction period 2. Transition drying period during the first year of operation 3. Operation & maintenance period over the remaining lifetime of the building  The key drivers for moisture exposure during construction include Inclement weather, moisture introduced by wet construction processes, site preparation & drainage, job scheduling & logistics, and materials transport & storage. Intrinsic moisture sources involve materials that are installed wet & are inherent to the construction process. Concrete masonry, poured flooring, and interior finishing processes such as joint treatment, painting & hanging wallpaper are good examples. These introduce large amounts of moisture into the building that must be safely dried out & removed but occur only in the early stages of the building’s life. Weather and episodic exposures such as a broken water pipe or other accident can soak materials and cause significant water accumulation at unpredictable times. Moisture accumulation can be alleviated or exacerbated by factors such as site drainage & flashing details. Certain materials, such as exterior sheathing & area separation walls, are unavoidably exposed to the weather during construction and require an added degree of robustness when rainy weather is possible. Likewise, wood framing can get soaked by rain, as can materials improperly stored or brought onto the site before the building is closed in, which adds to the intrinsic moisture loads and can lead to mold growth if the materials are not dried quickly. The first year after construction begins a transition period that must be considered in the moisture management strategy. Concrete basements and foundations will continue to release significant amounts of moisture for months to come and a safe path must be provided for this moisture to escape without accumulating where it can cause long term damage. Likewise, if the wood framing has gotten wet during construction, provisions to dry this out must be made to safely & quickly remove this moisture from the building. Poorly insulated or sealed elements of the exterior envelope will create cold spots that can result in condensation problems. The HVAC system (heating & air conditioning) can introduce myriad problems if the fans and ducts do not balance air pressures throughout the building or if improper drainage of cooling coils and drip pans lead to mold growth in the ductwork itself. Of course, leaky roofs, poor window flashings, and plumbing leaks can lead to serious problems when these details are not executed correctly. Finally, after the building has been fully dried out it still must handle moisture from the occupant activities, weather cycles and basic design & maintenance issues.   Weather & other episodic exposures Exposure to weather Exterior sheathing Shaft wall & Area separation walls Structural framing Building envelope leakage Plumbing leaks Building envelope leakage Plumbing leaks Avoidable Poor design & construction Poor mat’ls staging & storage Poor design & construction Poor HVAC design Improper HVAC operation Poor maintenance & repair

REDUCING THE RISK OF MOLD Lever Primary influencer(s) Manufacturer responses Exposure to moisture during transportation and storage Shipping companies Distributors Contractors Develop best practices guidelines Education/training Exposure to moisture during construction Develop best practices guidelines Education Contractors Drying of building materials Contractors Develop guidelines and specifications Exposure to moisture after construction Architects Contractors Maintenance companies Develop best practice guidelines Education The occurrence of moisture & mold is at the end of a lengthy chain of causalities that can individually or cumulatively contribute to the start of a problem & its ultimate severity. This allows us to identify a series of leverage points where moisture & mold control strategies must be included. The first issue is to deliver products to the job site that are clean & at a safe moisture content for each material. First, the manufacturer must take care to ship materials that are properly dried and in good condition. From there, it is incumbent on the shipping companies, distributors & contractors to protect moisture sensitive materials from getting wet during transportation & storage. During construction materials can get wet through a variety of mechanisms. The contractors are the primary influencers to prevent this or alleviate its impact. Contractors bear the ultimate responsibility for ensuring that the building materials are properly dried out, whether the moisture is from external sources like rain or from intrinsic construction moisture. In most cases, drying is left to chance with sometimes a little help from fans to provide forced ventilation when weather conditions are not conducive to rapid drying. This may not be satisfactory for staying on schedule or for removing moisture quickly enough to prevent mold growth and more aggressive drying strategies must be implemented. In many cases, bringing in a construction drying subcontractor to install temporary dehumidification equipment can be a cost effective way to stay on schedule and maintain quality. Controlling water exposure after construction requires proper design by the architects and engineers, as-built construction that follows the design, and proper building operation and maintenance. From the perspective of the product manufacturer, it is necessary to consider how the product will be used over its entire life cycle and then develop appropriate strategies for enhancing robustness against mold growth through the introduction of water-repellent additives, reduction of food sources within organic materials and the use of safe and effective biocides as necessary to provide products that meet all performance targets for strength, handling, finishing characteristics, moisture & mold resistance, etc. Water hold-out Product manufacturers Introduce water-repellent chemicals in products Food sources within building materials Product manufacturers Promote/develop inorganic offerings Biocides Product manufacturers Contractors Introduce safe and effective biocides into key products Influence-based Product-based

Spores + Nutrients + Water  Mold SUMMARY Spores + Nutrients + Water  Mold The key to mold control is moisture control “Molds can be found almost anywhere; they can grow on virtually any substance, providing moisture is present…” - EPA Materials must stay dry to prevent mold Systems manage moisture, products do not There is no simple product solution for mold !!! So, in summary: We are dealing with a very basic equation: Spores combined with nutrients and water will result in mold. Of these three, water is the only component that we can safely and easily eliminate from this equation. The key to mold control is moisture control. This is the only long-term winning strategy out there. Materials must stay dry to prevent mold. If there is no moisture, there will be no mold. Keeping water out requires designing & building systems that will properly shed water & are capable of drying out if water does get in. Systems manage moisture, not individual products by themselves. Substituting products that are resistant to mold will not provide an effective solution if moisture still gets into the structure.

OUTLINE Review Solutions Resources

OBJECTIVE Continue to the lead the industry in the development and positioning of products which address ALL critical attributes: Fire Resistance Sound Control Full spectrum of performance attributes Moisture Control While the moisture and mold issue is currently top of mind, USG plans to continue leading the industry in the development and positioning of products which address ALL of the attributes listed here. Abuse Resistance Aesthetics

Clear recommendations for the use of all products STRATEGY Increase intensity of Education & Communication Building science / research Product enhancement Clear recommendations for the use of all products To meet our objectives, we will continue to provide education and communication that supports our fundamental message: Education and communication Mold is a moisture control issue that must be managed by proper building design, construction and maintenance practices Building systems are the best method to control/minimize water infiltration and therefore mold growth Building science and research USG will continue to develop and communicate best practices to reduce the risk of moisture related problems. Product and systems development We will offer systems that address the full spectrum of performance needs for specific applications (Fire, Acoustic, Aesthetic & Moisture) Clear recommendations for all products In areas that are not supposed to be exposed to moisture, we will continue to support and promote our SHEETROCK Brand Regular gypsum panels. In areas where products may be exposed to some intermittent moisture before, during and after construction, we will continue to investigate and develop where appropriate, more robust products that address our customers needs and manage their risk. Lets take a look at one of USG’s latest developments

NEW SHEETROCK® BRAND HUMITEK Attributes Fire Resistance Sound Control Handling Finishing Moisture/Mold ASTM D3273 = “8” Thickness ½” 5/8” FC Width 48” Wide Edge Tapered Paper Light blue Moisture Resistant Core Patent Pending Mold Resistant Additive New end tape design Our newest product is named SHEETROCK Brand HUMITEK Gypsum Panels. This is a new category of gypsum panels, which has improved wet performance compared to WR board and also has mold and mildew resistance. It also carries the other attributes that are an integral part of all of our gypsum board products including fire resistance, sound control, abuse resistance and handling/finishing ease. In order to have the new product stand out, the paper is light blue in color and has a new end tape design.

NEW SHEETROCK® BRAND HUMITEK Where is it used? Areas subject to intermittent moisture Basements Garages Bathrooms (not tubs or showers) Areas subject to weather during construction Allows opportunity for building professionals to manage risk as needed SHEETROCK Brand HUMITEK gypsum panels have been developed for use in areas that are subject to intermittent moisture or high humidity before, during and after construction. These areas include basements, garages bathrooms and perhaps areas subjected to weather prior to the building being closed up. This product gives the architect or contractor the opportunity to manage their risk and increase their protection. Also, it is important to point out that USG will no longer support or recommend a “faced” product being used in wet areas such as tubs and showers. This includes both SHEETROCK Brand HUMITEK and the existing WR product. Therefore, the only products that we currently recommend for the use in tub and shower areas are our DUROCK Brand Cement Board and our new Aqua-Tough Interior Panel. To reiterate, in areas that are not subject to intermittent moisture, and should not get wet, SHEETROCK Brand regular gypsum panels be used.

NEW SHEETROCK® BRAND HUMITEK Installation Easy score and snap Setting Type compounds Paper joint tape Sheetrock Brand First Coat No itchy glass fibers No skim coating necessary Excellent performance without sacrificing productivity These panels score and snap in the same fashion as standard Sheetrock Brand Regular Gypsum Panels. However, to maintain a moisture resistant “SYSTEM” USG recommends the use of setting type compounds and paper tape to finish the joints First Coat is also recommended. NOTE: With the new HUMITEK Brand gypsum panels there is: No itchy glass fibers (this means a “good day” for installers) No skim coating required for an acceptable finish

ARCHITECT Architectural Record We understand that this is the type of product that needs to be specified. Therefore, we are promoting it heavily to the architectural, contractor and builder communities through a series of advertisements.

CONTRACTOR Walls and Ceilings and Construction Dimensions

BUILDER Builder Magazine

NEW AQUA-TOUGH INTERIOR PANELS TOUGH TO THE CORE Abuse Resistant Finishes like standard SHEETROCK Brand gypsum panels Tile shear bond strength exceeds ANSI standard Moisture Resistant Mold Resistant Fire Resistant Certified Green-Environmentally friendly Our new AQUA-TOUGH interior panels are the industries first abuse-resistant panels with moisture and mold protection. They are engineered to provide increased resistance to indentation and penetration over paper or glass faced gypsum panels. Making them ideal for use in high traffic areas in schools, hospitals and hotels. They hold ceramic tile in both wet and dry applications with shear strengths that exceed ANSI A118.9 the only other products that can make that claim are cement boards like our DUROCK Brand cement board. AQUA-TOUGH can do all that yet can be finished like standard drywall. It is an excellent choice for use in locker rooms and kitchens. Use as a ceramic tile backer for wet areas, even tub and shower surrounds. And AQUA-TOUGH is made from 95% recycled materials which is great for our environment.

USG PANELS WET AREA PERFORMANCE Relative performance Low High Relative Installed cost index Moisture resistance Mold resistance Ease of finish Product Tile bond SHEETROCK 1 SHEETROCK WR 1.10 SHEETROCK Humitek 1.30 FIBEROCK Aqua-Tough In wet area applications, panels should be specified based on the job specific requirements and on the appropriate level of “wet performance”. “Wet performance” encompasses how well a panel performs across a number of criteria which include moisture resistance, mold resistance, tile bond strength when wet and finishability. Because of variations in labor rates across the country, we have expressed the installed cost of each product using SHEETROCK Brand gypsum panels as the baseline with premium of other products expressed a percentage. 1.60 DUROCK Cement Panels 1.90

APPLICATION PERFORMANCE CRITERIA Mold and moisture-related products Systems Applications Products Attributes highlighted Interior wall Specialty panels Incidental moisture High moisture Cavity shaft walls Area separation walls SHEETROCK Humitek FIBEROCK Aqua-Tough SHEETROCK e+ shaft wall liner Tile backer board Tub, shower, and high-moisture areas FIBEROCK Aqua-Tough DUROCK Substrates Here is an overview of how our wet area panel products are positioned by application based on the full spectrum of performance attributes of each product. This is a summary of building environments that may experience intermittent moisture and where mold may be a concern. We believe that 95+% of interior applications should not be exposed to significant levels of moisture and remain ideal applications for our SHEETROCK brand gypsum panels. NOTE: We do not recommend WR panels (Greenboard) for applications that are exposed to excessive moisture or in tub and shower surrounds. These moisture conditions can lead to a mold concern. Floors Exterior FIBEROCK Aqua Tough DUROCK

OUTLINE Review Solutions Resources

RESOURCES Literature 800 USG.4YOU www.GypsumToday.com Leading – WB2332 Moisture Control – WB2325 ASTM D3273 (FAQ’s) – WB2324 Good Construction Practices – WB2334 Storage and Handling – WB2333 Repairing water-damaged building systems – WB2315 Facts (Moisture, Mold & Ceilings) – SC2414 800 USG.4YOU www.GypsumToday.com USG offers several literature pieces that discuss much of the information we’ve shared to day. The pieces listed here will help you and your customers gain a strong understanding of the moisture and mold issue.

RESOURCES USG also has a variety of resources on usg.com. These include both USG systems and products information and independent resources such as the Environmental Protection Agency (EPA), Building Science publications, ASHRAE publications links to several other sources.

MOLD IS A MOISTURE MANAGEMENT ISSUE The only controllable factor linked to mold growth is moisture Virtually any building material can be negatively impacted by mold and moisture if proper practices are not followed Mold must be managed by proper building design, construction, and maintenance practices There are no “silver bullets” to solve the mold issue Nutrients USG’s approach to this very important issue is to continue to communicate that “mold is a moisture management issue” and we are focused on being a “voice of reason”. We will continue to provide information to all of our customers to help better understand the issue and help manage your risk. We will also continue to further efforts on the “building science” front in terms of product and system testing and of course look to make product enhancements. We hope you have found the information within this presentation helpful today and welcome your comments and questions. We also want to take this opportunity to thank you for your business and continued support. Mold Spores (everywhere) Water (liquid moisture)