water intrusion, fungus - Solender Group
Construction Defect Experts

Microbiology & Fungi

Water Intrusion & Fungus


Allergies are the sixth-leading cause of chronic disease in the United States and are estimated to cost the health care system more than $18 billion annually. It is estimated that up to 50 million Americans have allergic diseases. Statistics show that allergies are present in as many as 78 percent of asthmatics and can trigger asthma attacks. The prevalence of asthma is increasing rapidly in the United States, and the disease causes more than 5,000 deaths annually.

Factors contributing to allergic diseases include allergen sensitization, continued allergen exposure, and environmental irritants. The most common exposure route for allergens is through inhalation, but also includes ingestion and contact with the skin and mucous membranes. One very common cause for indoor allergen exposure is through water damage to building structures and subsequent mold growth. Mold growth may appear within 48 -72 hours of water intrusion if not properly re-mediated. Molds, both indoors and outdoors, can be an enormous factor contributing to allergies. Sampling for molds can be an excellent indicator and cost effective means of determining possible environmental factors contributing to allergic diseases.

Health effects vary tremendously, depending on the individual, dosage, and route of exposure. The fact that the bacteria do not have to be alive for endotoxins to pose a serious health threat is the main impetus for concern. One major route of exposure is in the bloodstream, which on occasion, occurs by absorption through the gut. Although gram-negative bacteria are normal inhabitants of the gastrointestinal tract, when the natural host defenses are impaired, bacteria can be introduced into the bloodstream or lymphatic system. Another way that bacteria can enter the bloodstream is by infection of by introduction in surgical procedures or medicines. Once in the bloodstream, endotoxin levels as small as two hundred parts per trillion (on a body weight basis) causes fever and as small as one part per billion can cause shock and death. In response to this very real potent threat, medical device manufacturers and pharmaceutical companies now routinely test all of their products to ensure that they are free of endotoxins.

Another way individuals may be exposed to endotoxins is by inhalation of bacterial cells or fragments, which is the object of this discussion. Reported acute symptoms of inhaled

Exposure to saprophytic fungi (molds) in indoor environments has been linked to a number of adverse health effects including, but not limited to, lethargy, allergies, asthma, infection, dermatitis and hypersensitive pneumonitis. While the aforementioned symptoms are intuitive and largely recognized by both the scientific and lay communities, there are significant secondary health effects associated with exposure to fungi, including idiopathic pulmonary hemosiderosis in infants, cytotoxicity, cognitive impairment, encephalopathies, immunosuppression, and cancer.

Research indicates that these secondary health effects may be caused by the mycotoxins produced by the fungi. Although still controversial, in the end mycotoxins may prove to be major components in the health effects reported by victims of fungal exposure.



The search for the cause of the excess moisture that promotes microbialbal infestations runs an often predictable course. Roofs, windows, HVAC, plumbing, irrigation systems and water evacuation systems should all inspected and evaluated.

Most construction defect (CD) attorneys now believe that water damage plays a leading role in nearly all construction defects cases. Therefore water intrusion are important because of the consequential damages generally attributed to such water damage

Windows and roofs are a prime candidates for providing the leaks that afford consequential damages to so many construction elements in all types of buildings. During testing procedures, if a window leaks it leaks either at the window product corners or at the frame, or at the sill track due to overflowing or with the glass installation or window itself or any combination of these various indivdual problems. Although this leaking problem is found to be quite common, it is the installation of the windows rather that the window product that most often reveals a leak. When selecting windows for random testing, the preferred windows selected for testing should be free from apparent water staining on the surrounding plaster so as to assure a random sampling. Windows with plaster stains or plaster deformations around them should be summarized in a separate category for separate testing.

The most important area of window installation, is the installation of the surrounding flashing during framing procedures. This necessary flashing element requires that its installation be correctly integrated with the stucco lath so as to assure its water-tight integrity. There are literally dozens of ways to install this required flashing, but only a couple of ways to install it correctly so as to prevent leaks into the building envelope.

Unfortunately, upon invasive investigation, it is often found that the flashing installers have selected one of the many incorrect ways. Even when the flashing is correctly installed it is often found that the stucco lathing installer failed to properly integrate the lath with the flashing. The result is that the system as installed will leak into the interior of the building, sometimes with a tiny drip and sometimes with a small stream of water. The interior insulation will absorb some of the moisture as will the lumber and the interior of the gupsum plaster with this moisture providing the catalyst for the necessary food source for the growth and propagation of the fungi and mold.

One of the most common sources of leaks accompanied by consequential damages, are roof leaks. The materials utilized generally being up to the industry standards, but the methods used in applying the various roofing elements into a watertight cohesive bundle, are frequently inadequate. Roof leaks are sometimes hard to locate, with some manifesting themselves hundreds of feet from the source of the leak source, but are often more complex from a discovery point of view as well as from the remediation requirements. The faulty installation of the various component parts, especially the proper integration of the sheet metal flashing and counter flashing elements, is a prime source of serious water leaks. To a less frequent degree HVAC units, irrigation lines, drain lines, on grade slabs and sewer lines all can cause damage with consequential effects. When any of these leaks occur, numerous other construction elements can be impacted, some with serious side effects.

Since most construction defects cases start off with a leak from either plumbing lines or from exterior sources, it is imperative that measures be taken to ensure that water pipes are not leaking and that the exterior elements of the house are in a watertight condition.

When these and other potential sources don't answer your questions, it may be wise to look under foot. Vapor transmission in concrete slabs is the leading cause of flooring material failure. The same vapor that causes a failure in floor coverings can be the source of microbe promoting moisture.

Vapor transmits from the ground, through the slab, and into the building envelope by a difference in Vapor Pressure. Vapor Pressure is a number mathematically derived from a combination of temperature and humidity. If sub-slab conditions are damp and cool, the warmer and dryer the building envelope is the greater the emission levels will be produced.

Potential indicators of concrete slab vapor transmission include:

1. Discoloration or bubbles in sheet vinyl flooring,

2. Dark lines and curling in vinyl composition tile,

3. Dampness under boxes and chair pads,

4. Direct glue carpet peels back easily,

5. The slab is a dark gray under the flooring,

6. The slab has no vapor barrier,

7. Tests and inspection of underground pipes shows them to be in poor condition,


If a proper vapor barrier is used for the construction of the slab the only major concern is with the water in the concrete. If there is no vapor barrier, any testing is only a snapshot, and will most certainly vary with the exterior and interior environmental changes. The transmission of vapor cannot be controlled by HVAC systems alone. The floor must be correctly sealed in order to bring emission levels into compliance. Testing is done using anhydrous calcium chloride. Test results are expressed as pounds of water per 1,000 square in 24 hours.

The flooring industry standard for most applications limits the allowable level to below 3 pounds. Experience shows that some floor coverings can handle higher emissions. Among these are vinyl composition tile, ceramic tile, and glue down carpet. If there is a failure of any floor covering, there may be enough vapor to promote microbial growth. If no failure is evident, there can still be emission levels high enough to cause problems.

Microbial contamination due to concrete vapor slab transmission is another area that should be considered. Under certain conditions microbial growth will occur from failed or non-existing flooring vapor barriers and this can have an enormous effect on the formation of bioaerosols and subsequent poor air quality. Proper vapor barriers are essential to prevent vapor transmission that can lead to this microbial contamination.

One significant facet of many indoor air quality microbial investigations is the assessment of the carpeting in an occupied building. Carpet is listed as one of the nine potential sources of biological agents in an occupied space by the American Conference of Governmental Industrial hygienists. The difficulties in assessing carpet contamination arise from the porous nature of the material, lack of standardized sampling methods, and obscurity of data interpretation.

Carpeting can be found in almost any building. The aesthetic values of sound dampening and enhanced appearance are important to a productive work environment and a comfortable home environment. Carpet can also be a reservoir for many contaminants including dust, pollen, bacteria, and fungi. These contaminants are typically ubiquitous in most envireonments, but complications arise with poor carpet maintenance (cleaning) and/or water damage incidents.

Q: What are some of the biological problems I should be concerned about?

A: Molds, mildew, fungi, bacteria and dust mites are some of the main biological pollutants inside your house.  Mold and mildew are generated in the release spores into the air.  Mold, mildew, fungi and bacteria are often found in areas of the home that have high humidity levels, such as bathrooms, kitchens, laundry rooms or basements.

Q: What are some of the health effects?

A: Allergic reaction are the most common health problems associated with biological pollutants. Symptoms often include watery eyes, runny nose and sneezing, nasal congestion, itching, coughing, wheezing and difficulty breathing, headache, dizziness and fatigue.

Q: How are biological contaminants transported through the house?

A: Molds and dust mites thrives in areas of high humidity.  Mold grows on organic materials such as paper, textiles, grease, dirt and soap scum.  Molds spores float throughout the house, forming new colonies where they land.  Dust mites thrive on dead human skin cells and in textiles such as bedding, carpeting and upholstery. When these textiles are disturbed during vacuuming, making beds or walking on carpet, the dust particles become airborne.

Q: If Iím concerned about the biological contaminants in my home, what kind I do to deal with the problem?

A: There are no practical tests for biological contaminants for use by non-professionals. However there are signs to watch for. You can sometimes see and smell mold colonies growing on surfaces.  Mold growth should be should be suspected wherever there are water stains, standing water or moist surfaces.

Prevent mold growth by keeping basements, bathrooms and other rooms clean and dry. Use a disinfectant to clean surfaces that have mold on them. If carpeting or furnishings become wet, they must be quickly and thoroughly dried or discarded.  Humidifiers, dehumidifiers and air conditioning condensing units should be regularly cleaned with a disinfectant such as chlorine bleach.  Keep humidity at acceptable levels (less than 50 percent) and make sure thereís plenty of ventilation, especially in areas where moisture tends to build up.

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