By Steve Easley
What makes your business or any business successful really isn’t how much money you make, how many products you sell, or for builders, how many homes you build a year. What makes a business successful is how much money you keep. The building industry is still spending billions of dollars each year in unnecessary payouts and repairs due to water intrusion and mold-related problems that could be avoided. Every dollar in payouts is a dollar of lost profit.
Long gone are the days when homeowners would ignore mold in their homes. Six years of heavy media coverage have educated homeowners that mold is not an issue to be ignored. Many states require disclosure of water and moisture problems, including mold. This becomes an investment issue for owners and they are demanding that mold problems be professionally handled. The old “spray it with bleach” just doesn’t cut it anymore. For lumber dealers and their customers, it is important for image and liability reasons to handle these issues promptly and professionally, with the right materials and resources.
I was speaking with a builder just the other day on this issue and he told a story I hear all too often about how a simple mistake turned a $3,000 repair into a $40,000 mold remediation because an employee did not follow industry standards for proper containment before mold removal. Arming employees with up-to-date knowledge of what we have learned in recent years about mold and proper remediation is critical to risk management and the profitability of your business.
In this inaugural article for what will become a monthly column offering advice from the experts, I interview Susan Raterman, a certified industrial hygienist with more than 25 years of experience. Susan specializes in construction-related mold problems. Susan consults with builders and lumber dealers across the country, teaching them (and their employees) how to respond to mold claims. She also develops remediation protocols, monitors clean-ups and provides litigation support.
“How much of the mold problem today is real and how much is media hype?”
Susan: Mold is a very real problem to individuals who are allergic to it, especially if they live in a house with significant mold growth. Although mold is in the forefront of the media, the negative impact that elevated moisture in a building has on the indoor air is beyond that of just mold growth. Bacteria, dust mites and other microbiological agents are capable of causing adverse health effects among some individuals. Studies have indicated that 40% of indoor air quality complaints in buildings in the U.S. are attributable to mold and bacteria.
Mold is also a very tangible problem to builders and homeowners because it can stain and biodegrade the organic substrate on which it grows. Molds growing on the surface of wood and wood products discolor the surface through production of pigmented spores. Decay fungi growing on wood will attack the structural polymers in the fiber, reducing its strength.
Lastly, the multi-million-dollar settlements and verdicts in construction defect and personal-injury mold-related lawsuits are very real. Lumber dealers are being named in mold lawsuits along with builders, subcontractors, architects and building product manufacturers. Design and construction practices that prevent excessive moisture are important to builders and architects from the perspective of profits, customer satisfaction, construction-defect liabilities and long-term reputation. According to Cahners Residential Group (2000, 2001), more than 66% of new-home buyers are willing to spend an additional $2,500 to $5,000 for features that enhance indoor air quality, energy efficiency and resource conservation. However, homebuyers certainly do not expect to pay extra for a home free of construction defects that cause moisture and mold problems.
“How can you prevent mold from growing on lumber?”
Susan: The short answer is keep it dry and dry it if it gets wet. But tackling the challenge of preventing mold on lumber during storage, transportation, construction and home ownership requires an understanding of why mold grows on wood. Molds have four basic requirements for growth: suitable temperature, oxygen, food and moisture. Eliminating one of these required elements can prevent fungal growth. Wood contains sugars and starches that provide the nutrient source that mold requires. As unseasoned framing lumber dries, surface moisture appears, frequently creating conditions for mold growth. Since it is impractical to control oxygen and temperature in a lumberyard or a construction site, controlling moisture is the best way to control mold growth.
According to experts, including WWPA (2006), when the moisture content of the wood is reduced to below 20%, mold growth can no longer be supported. Depending on climatic conditions, lumber used in construction will typically dry to below 20% moisture content before the structure is enclosed. Prior mold growth, while not actively growing, may still be visible. Drying lumber reduces the likelihood of mold formation, but it does not guarantee the wood will remain free of mold. Lumber that becomes wet from rainfall or condensation after it has been dried will support mold growth.
There are some simple steps that can be taken to prevent mold growth on lumber during storage and construction, starting at the lumberyard. Wood and wood products should be stored undercover in a dry location. Product should be inspected before it leaves the yard to assure that moldy lumber is not being sent to the customer. To reduce claims, prudent lumber dealers have a program of mold inspection and cleaning prior to delivery of lumber.
Using lumber and gypsum board that has been stored outside in the rain or snow during construction introduces a significant moisture load into the home. Builders should use just-in-time scheduling to take delivery of moisture-sensitive materials, and keep them dry before use. By all means, make sure materials are not stored in puddles of water. Even “dry” lumber contains some moisture. Wet pieces inside wrapped bundles of lumber could create conditions for mold growth. For example, exposing the bundle to direct sunlight could heat the lumber and evaporating moisture can be trapped in the wrapping. Even that trapped moisture can be sufficient to support mold growth.
Builders face the very real challenges of rain, snow and hurricanes during construction. If wood gets wet during construction it is important to dry it out before gypsum board is installed. Use a moisture meter to check moisture content. A good rule of thumb for most wood species is that the moisture content should be below 19% or 20% before it is enclosed. In humid climates as well as in rainy conditions, mechanical drying may have to be introduced on site to reduce moisture in the wood, concrete slab and gypsum board. In hot weather mechanical dehumidifiers are effective, but in cooler weather desiccant dehumidifiers will work better. Air movers help to distribute air throughout the building and provide drying action across the surfaces of materials. In extreme circumstances where the building materials are wet, humid conditions prevail and schedule is critical, temporary enclosures of wet areas will reduce drying time and
increase its effectiveness.
Remember though, the challenge of controlling moisture does not begin or end with just using dry materials. Moisture in the home results from outside sources like rain, floods and groundwater penetrating through a poorly sealed building envelope. Moisture is also caused by indoor sources such as occupant-generated moisture from humidifiers, inadequate bathroom and kitchen exhaust and clothes dryers vented into the house. Design oversights such as omitting breathable water-resistant barriers and window flashing details can result in significant intrusion of moisture into the walls of the building. These and other poor design and construction practices can result in indoor environmental quality concerns and complaints of adverse health effects among the building occupants. By controlling relative humidity and water intrusion, the relative contribution of mold, bacteria and dust mites in degrading air quality can be minimized. Also minimized is the likelihood of moisture-related construction-defect lawsuits.
“What should I do if I see mold growing on lumber in the yard or on a job site?” Susan: Most “lumberyard” mold is fungi that discolor the surface of the wood through production of pigmented spores that can be green, white, pink, orange, black and other colors. The mold growth and discoloration is usually confined to the wood surface. The second type of fungi associated with wood is stain fungi. Stain fungi discolor the wood more deeply and are not as easily removed. These fungi may produce some discoloration as they grow on the wood surface, but the primary effect is a darkening stain that occurs as they grow deeper into the wood, known as “blue stain.” In instances where wood is chronically exposed to water, wood decay fungi can colonize. Decay fungi can penetrate more deeply and attack the structural polymers in the fiber, reducing the strength of the wood.
When you find mold growing on lumber in the yard or on a job site, prudent action will depend on the amount of mold, the type, as just described, and the likelihood of its disturbance. Pigmented mold spores growing on the surface of wood and wood products should be cleaned by wet wiping or wet vacuuming the surface, followed by scrubbing with water and detergent, drying and HEPA vacuuming the surface. Individuals performing this work should wear gloves, eye protection and a NIOSH-approved respirator.
Stain fungi, though they discolor the wood, will not pose an air quality problem and are less likely to pose a threat to the structural integrity of the wood. These fungi do not require removal. Decay fungi can create long-term liability because they eventually will affect the strength of the wood. Lumber with decay fungi present should not be distributed and used in construction.
Mold removal becomes more complex when there are heavy amounts of growth on a majority of the lumber, or if the building has been in service for some time and the mold originated from leaks into the building cavity. In these instances, a professional remediation and restoration company should do the mold cleanup.
“Why can’t I just spray bleach on mold to get rid of it?”
Susan: The mere application of bleach to moldy surfaces does not provide a long-term solution. While bleach may remove the mold stain, it does not remove mold spores, which can still cause adverse health effects even if they are dead. Further, the effectiveness of bleach is reduced in contact with residual dirt. Mold should be physically removed from materials contaminated with mold. If mold and bacterial growth resulted from black water or contaminated floodwater, materials should be disinfected with an EPA-registered disinfectant that does not have the adverse properties of bleach and physically remove the mold. Bleach can cause corrosion of electrical and mechanical components. Most importantly, bleach is a lung and skin irritant and if workers are not adequately protected exposure can cause serious injury.
“What if the builder uses the moldy lumber supplied by my company in constructing homes?”
Susan:
I have been involved in some cases where a homebuyer will walk the construction site, discover moldy lumber and refuse to move forward with the purchase until the wood is replaced or the mold is remediated. Responsibility for remedial action often falls on the lumber dealer.
Despite the fact that there is currently limited research about whether “hidden” mold can move into the structure and increase the amount of mold spores in the indoor air, homeowners are concerned. Concern frequently escalates into fear, and is followed by litigation. In many cases the discovery of the moldy lumber hidden within walls and in the building envelope occurs only after a pipe leak or a strong odor is detected in the home. It is sometimes very difficult for investigators to determine the cause of the mold growth and assess penalties to the responsible parties commensurate with their responsibility for the mold growth.
For these reasons and others, the best and most protective policy is to inspect lumber before it is delivered to builders and take return on product that was mistakenly delivered with significant amounts of visible mold.
“How is a proper mold investigation conducted in a completed home?”
Susan:
A proper investigation performed by a qualified professional identifies:
• Sources of moisture
• Locations of visible microbial growth
• Locations of potential microbial growth
• Possible pathways of dissemination of airborne microbials in living spaces
• Health complaints among occupants
At minimum, the investigation should answer these questions:
• Is there mold growth and where is it located?
• What caused the mold growth? Was the moisture generated by an outside source or an indoor source?
• What impact does the mold have on building materials?
• Are there other microbial organisms suspected, such as bacteria and dust mites?
• Is surface sampling warranted? If so, what type of sampling and where?
• Is air sampling advisable? What type of sampling will best achieve the goals of the survey?
• Is remediation necessary and what is the best approach?
“Who is best qualified to perform this type of investigation?”
Susan: A professional consultant with education and experience in industrial hygiene, indoor air quality, building science and construction is best suited to the job. If the scope of work includes the task of determining whether or not air quality has been affected by the presence of mold and microbials and any related exposure risk of building occupants, a certified industrial hygienist with experience in indoor air quality, building science and construction is the best choice. Consult the American Industrial Hygiene Association Consultants Listing at www.aiha.org to locate certified industrial hygienists with expertise in mold investigations and sampling.
“If mold growth is found in a completed home, what should be done?”
Susan: The answer to this question is dependent upon many variables related to the building’s construction, extent of the mold growth, damage to building materials, mold in the HVAC system, contamination of contents and the impact on the health of the building occupants. In all cases, prompt, well thought-out action should be taken as soon as possible after the problem is identified. The following actions should be implemented regardless of the size and complexity of the mold growth:
• Stop the moisture intrusion.
• Establish appropriate containment and worker and occupant protection.
• Dry the affected area, decontaminate or remove damaged materials.
• Permanently abate the moisture intrusion problem.
These actions may be taken by the builder’s personnel if the area of contamination is small and they are made aware of the proper techniques to use so that mold is not dispersed into the environment. For larger, more complex problems, the consultant should develop a scope of work to be implemented by a professional mold remediation company. Porous building materials with visible mold growth such as gypsum board and insulation should generally be removed and replaced. When a significant amount of mold is found on wood and wood products, appropriate remediation methods range from surface cleaning to sanding to media blasting, which removes the growth and a thin layer of the affected wood. All forms of mold remediation should be performed in a manner that does not disperse mold spores into the air, protects the individuals doing the work and protects the environment from contamination.
“We recognize that not all mold problems are caused by moldy lumber. What causes some of these costly problems and how can they be prevented?”
Susan: Some of the most common construction defects are leaks from water intrusion in the building envelope. These defects frequently occur due to improper detailing and sealing of water entry points in locations including windows, walls, doors, hose bibs, air conditioning line sets, plumbing and electrical penetrations. Moisture intrusion often results from not using breathable water resistant barriers and flashings at walls, windows, doors and the roof. Other entry points that should not be ignored are foundations, basements and crawl spaces where excessive moisture is often due to poor site drainage and improper foundation waterproofing.
“What is the best advice you can give to lumber dealers to reduce their exposure to liabilities surrounding mold?”
Susan: As an industrial hygienist, the best advice I can offer lumber dealers is to develop a written mold and moisture control plan, train your staff and put the plan into action. The plan should address proper storage of wood products, quality control inspection procedures, how to detect mold, how to remove mold, when to get expert advice and what to do when moldy lumber is mistakenly distributed to customers.
STEVE EASLEY, president of Building Media Inc., has more than 30 years experience in the construction industry, including 10 years as a professor of building construction and contracting at Purdue University. For more information, see www.buildingmedia.com. Contact Susan Raterman of The Raterman Group, Ltd., at susan@ratermangroup.com.
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