Build It, and They Will Come
Fungi can grow in a variety of environmental conditions, from sopping wet to somewhat dry, through a broad range of temperatures, and on a variety of organic materials. The common link is that fungi require nutrients and moisture to grow. Lacking any internal digestive systems, they gather and break down their “food” from surrounding surfaces. Such sources may include attacks on dead organic materials and even other living organisms. Many of what we consider to be problematic molds in our indoor environments have an appetite for cellulose.
Unfortunately, our dilemma lies in the fact that we’ve taken to building our homes, offices and schools literally out of paper– in the guise of gypsum wallboard products (even the Three Little Pigs knew enough not to build their houses out of paper). Since many molds have an appetite for cellulose, any paper, cardboard, lumber or other “was-wood” products (manufactured wood products like OSB, particle board, etc.) will do nicely. Just add water!
Our concern for the proliferation of these microorganisms in our indoor environments is fundamentally driven by their potential for adverse health effects and their ability to cause extensive damage to buildings and personal property. Out of this, of course, stems the issue of liability – to commercial property owners, designers, builders, insurance carriers, service contractors, school districts, product manufacturers, and now indoor environmental consultants and remediation contractors! Attorneys all over America geared up for the microbial litigation “mold rush” by attending specialized legal seminars on the topic, even perhaps to the point of fueling the industry. Health concerns, property loss and liability are a potent combination for creating both opportunity and hysteria in this fledgling indoor environmental industry’s attempt to deal with an age-old problem.
Eating You Out of House & Home
Aside from the real concerns about adverse health effects from exposure to microbial contaminants indoors, there is the issue of property loss. And this can be staggering! Consider the loss of your property, either your home or commercial space, along with many (if not all) of its contents. Now add to that the cost of relocating for the time it takes to successfully assess, remediate, reconstruct and refurbish all the damaged property. Keep in mind that many people are finding out the hard way that their insurance company will not cover these losses due to the numerous exclusion clauses in most policies. Oh, and even if you can pay to fix the problem, don’t forget the stigma associated with a property that has had a significant microbial loss—potential buyers and lenders aren’t enthusiastic about a moldy building. Also, be sure to toss in how difficult it may be in the future to insure the property after a reported mold claim.
While there is still debate regarding the potential occupant health effects resulting from microbial contamination, there is little doubt that the financial trauma from property damage is real. In many instances, owners left without insurance coverage and faced with the burden of paying for a large microbial remediation project have little choice but to walk away from their property and default on their mortgages. We’re talking about walking away from everything you’ve worked for, in some cases.
A large portion of the undesirable fungi you hear about typically damage only finished surfaces along with affected building contents. Prolonged excessive moisture conditions in a wood framed property, however, can lead to structural compromise that may ultimately doom the entire building. However, fungal damage isn’t only limited to wood-framed buildings. Even concrete and metal structures have their Achilles’ heels when it comes to mold infestation. Gypsum wallboard, cellulose-based ceiling tiles, insulation and fireproofing materials are some of the products that often fall prey to mold attacks.
Wet It, and They Will Come…Sooner
If there is one underlying issue in this mold/microbial mayhem, it’s the moisture. Spores are everywhere: in building materials, in our furnishings, on our indoor surfaces, and even in the air. Our dwellings and their contents are potential food sources for these microbes because they are largely comprised of organic materials. Fungi and bacteria do not grow in the air; they grow on environmental surfaces. These are universal truths. Why, you may ask, do only some buildings become infested with mold or other microbial contaminants? What should be the obvious answer is, of course, moisture.
Typically, fungus growth requires an environment with a water activity (represented by the acronym – Aw) of greater than 0.7 at the surface. A material with an elevated moisture content (MC) will often provide a suitable surface Aw to promote microbial growth.
Keep your indoor environments dry, and these microorganisms cannot germinate and grow. Attempt to clean up a microbial problem and neglect an underlying moisture problem that promoted the growth, and (in time) your best-attempted efforts will fail. The surprising part about all of this is how often builders, property owners and even environmental consultants and remediation contractors, overlook these amazingly simple concepts.
The obvious moisture problem in a building occurs as a result of a sudden water episode, such as a flood. The southern gulf coast and Atlantic seaboard regions of the U.S. have yearly hurricanes and other catastrophic weather events that bring massive amounts of water into buildings, and result in microbial contamination. In such cases, unless all the affected porous and semi-porous building materials and contents are addressed immediately, contamination will likely occur in short order. Can we simply dry everything out and prevent fungal problems? Possibly, although in actual practice this is (at best) difficult to accomplish quickly enough to guarantee that you won’t have subsequent microbial growth.
You need to also consider the nature of the water that came into the building. Clean water from a potable source, like a broken supply plumbing line, doesn’t usually pose an immediate microbial health risk to occupants. In most cases, if the affected wetted building materials and contents are addressed (removed/replaced or rapidly cleaned & dried to normal state), mold problems will be prevented or at least greatly minimized.
Floods from ground water or sewage systems may contain serious microbial agents, such as bacteria and viruses, which pose an immediate hazard to human exposure. Good practice typically dictates that, in these cases, all porous materials that have come in direct contact with this type of water loss should be discarded and replaced. This course of action is warranted due to the likelihood of direct contamination from the polluted water source itself. Left un-addressed, such water events can also eventually lead to fungal growth in the indoor environment—creating a potentially nasty “one-two punch”
UN-Wanted, Dead or Alive
A common public misconception is that only “toxic” or pathogenic fungus such as the infamous Stachybotrys chatatrum is a problem for us. This, in fact, is not the case. Exposures to elevated levels of what are generally considered non-toxic / non-pathogenic organisms, like Cladosporium, which is one of the most commonly found molds outdoors, can lead to hypersensitivity reactions in people.
Another fallacy is that only “live mold” can hurt you. This mindset has spawned a bunch of purported chemical solutions to mold growth indoors—just spray on a “mold killer” and your troubles are over! This is only partially true. Chemicals that kill fungal spores do eliminate the chance of those spores from colonizing, thereby neutralizing pathogenic fungi from creating infections in our bodies (beneficial for surgical procedures at healthcare facilities, etc.), and preventing the growth of the treated spores on environmental surfaces. But many of these “mold killers,” or biocides, as they are referred to, have their own baggage associated with them.
Biocides often release other toxins into our environment. Be leery of “safe” biocides, as that term is truly a misnomer! Remember, the term “bio-cide” means “life-kill.” Fungal spores are some of the most resilient living structures on the planet—it takes a powerful process to have a truly sporocidal (spore killing) effect. Sporocides, by necessity, are toxic chemicals. These types of chemicals are often used to sterilize surgical instruments and food processing equipment, where direct human exposure is carefully controlled. These same sporocide products may pose a significant exposure hazard if used in our general indoor environments. Most “safe” processes probably won’t kill all the spores, and if you don’t kill them all, what’s the point?
Most of the fungal-related health concerns we face do not involve infections from pathogenic fungi. For the most part, exposures to either viable (live) spores or non-viable (dead, damaged) spores create the same allergic or toxic effects in our bodies. These effects may also result from exposures to fragments of spores or fungal structures. The solution is to remove materials with colonized fungal growth from the indoor environment, correct the source(s) of moisture that led to the problem, and restore the indoor environment to levels that somewhat parallel outdoor fungal conditions.
Is it realistic to completely rid our indoor environments of all fungal spores? Unless we all decide to take up full-time residence in pharmaceutical clean rooms, the answer is probably not. And, except for extreme immune-compromised health cases, it’s not warranted. It is reasonable to find similar levels and rank orders of fungal spores indoors as those concurrently found outdoors, period. Ideally, we would like to see lower levels of the same organisms inside, but even moderately higher levels of the same organisms indoors at a specific point in time is usually no cause for alarm. Ultimately, the best advice for limiting mold problems in your building is to keep it dry. If the property is subjected to a sudden moisture event or an ongoing moisture problem, correct it now, or you’ll probably have to pay dearly later.
For additional information on dealing with mold and other microbial concerns, check out our Cover Story from the May 2016 issue of Healthy Indoors Magazine at http://hi.healthyindoors.com/i/680154-hi-may-2016/7