Stachybotrys chartarum (atra) has crept into the limelight over the last decade, becoming one of the most feared bio threats in modern home building. Lawsuits in New York alone are making claims for construction defects and mold ranging from $65 million to $8 billion. In California Senate Bill 732 the“T oxic Mold Protection Act”, went into effect January of 2001. It is the only legislati on of its type throughout the United states. The Act seeks to address threats to human health caused by mold in indoor environments. Among other things the Bill calls for the crea tion of a task force that will identify “acceptable levels” of mold contamination in residential environments. This will work in conjunction with newly adopted toxic mold disc losure laws to give standards for builders and home owners to address if they find themselves in mold concerned litigation. The greenish-black fungus thrives in water damaged high-cellulose materials where it can rapidly colonize substantial surface area when gone unchecked. The fungus feeds on organic materials and as a byproduct produces toxins that can be released into the living space. The following was excerpted from Real Property Law Reporter, January 2002: “The health risks associated with these toxi c molds are significant enough that respected authorities (such as the New York City Department of Health) suggest that affected areas of any significant size be entirely contained, with airlocks and a decontamination room, and removal be conducted by personnel trained in handling hazardous materials under the supervision of a health and safety professional with experience in performing microbial investigations.” Not surprisingly, this can ge t expensive. This combination of high cost, publicity, and health concerns is conducive to, and has resulted in, considerable litigation and a growing number of claims for insurance coverage, including first-party building coverages.
The Problem we face:
The New York City Department of Health published “Guidelines on Assessment and Remediation of Molds in Indoor Environments” as the definitive text in the identification and treatment of toxic molds. That text defines five levels of contamination and the appropriate way to address those infestations. Th e report consistently refers to the square footage of mold coverage in relation to the number of contaminated ”wallboard panels” as the measurement by which that level is determined . For instance a Level III infestation is defined as “Level III: Large Is olated Areas (30 – 100 square feet) – e.g., several wallboard panels”. The report focuses its attention on “wallboard panels” because those panels are the environment in which the mold thrives. The simple fact is: Though it is impossible to eliminate all mold and mold spores in an indoor environment, builders and sub contractors can adopt technologies that reduce the possibility of these infestations. The Environmental Protection Agency website states “The key to mold control is moisture control.”. For tile contra ctors moisture control in wet areas has always been the foremost concern. We are all very much aware of the havoc water can cause when it finds its way out of its intended path down the drain. Water migrates through mortar and cement backerboards, it wicks up and over water barriers, sneaks through cracks and generally has a habit of getting where it does not need to be. When that moisture meets the gypsum board behind the mortar installation in our showers it is absorbed and continues to migrate. It causes grout discoloration, bond failure, rot and of course mold growth.
A Practical solution:
In order to reduce the risk of infestation we must eliminate the environment and conditions that are conducive to mold growth. To do this we must remove all gypsum board (no matter if it is specially treated or not, they were also eliminated in the 2006 IRC from any wet area); secondly we must eliminate moisture penetration in those areas. Simply put no gypsum, no water, no mold. If other surfaces or backerboard materials are installed such as cementitious backer units or fiber cement boards, one need to know that these are only water resistant but still absorp and pass water and especially water vapour to the wooden construction where the real problem will grow. All these substrates need to be waterproofed additionally. All seams, jo ints, penetrations as well. Mesh tape and thinset adhesives do not waterproof any tile installation. Because this is fact, none of these manufacturers covers the mold issue in the wooden construction with any warranty, nor does any insurance company cover any contractor work regarding mold issues anymore. This situation must be clear to everyone, otherwise this problem will not be solved in any predictable and successful wa y or form. Another solution that the industry offers can simplify the installations and eliminate the mold concerns in a most practical and efficient way.
In Germany the wedi GmbH has been producing a waterproof (as opposed to the known water resistant) tile backerboard for 25 years. The board consists of an extruded polystyrene core, it is coated with a glass mesh tape and polymer-modified mortar. The board has no food value to promote the growth of microorganisms. It is absolutely waterproof due to the properties of the extrusion process that creates a closed cell foam. When all joints and attachment points are treated with a waterproof caulking the system offers what no other tile backer product can, a waterproof, stable installation engineered to be installed directly to stud. It succe ssfully protects the whole construction and therefore secures your investment in your home.
Unfortunately, there is little hope of to tally eliminating the presence of Molds everywhere. What we can do is not create petri dishes behind our wall.