A Mold Case Study
Unit 2, 3207 Harbor Village Road- Middleton, WISCONSIN
LIMITED MOLD EVALUATION
IHSC PROJECT NUMBER: W04-439
On Thursday January 29, 2004, IHSC conducted an inspection of Unit #2 of the condominium complex located at 3207 Harbor Village Road in Middleton, Wisconsin at the request of Mr. John Green. It was reported to IHSC that there was visible fungal growth on sheetrock within the master bedroom, master bathroom hallway and coat closet of the unit.
The subject structure is a two story – multi-unit condominium complex. Unit #2 was found on the ground (garden) level of one of the condominium buildings. Unit #2 consisted of a one-bedroom condominium with (generally) open living area (dining and living areas), kitchen and two full bathrooms. A vaulted ceiling was present above the master bedroom and living room areas. The unit is equipped with baseboard heating and a ceiling mounted air conditioners. Unit #2 was finished with sheetrock walls, and carpet and sheet vinyl flooring. The exterior construction consisted of block with a brick façade. The scope of this evaluation was non-destructive in nature and was limited specifically to the visibly accessible areas of Unit #2.
It was reported to IHSC that the roof had leaked in the past. Approximately four years ago the roof began to leak above the south portion of the living room. Since the leak was first discovered repairs were made at two separate occasions but some leaking persisted until the roof was finally replaced in September of 2003. The owners’ representative also indicated water issues also occurred in the master bathroom and master bathroom corridor, which is located along the south exterior wall of the building. The owners’ representative indicated it was initially thought to be a leaking toilet gasket. However, the problem periodically re-occurred after the gasket was replaced. The owners’ representative indicated he later discovered a rain leader, which was located on the outside wall along the bathroom, was damaged and discharging along the foundation of the building. The owner did indicate the damaged rain leader had been replaced. The owners’ representative also stated that this past summer the wallpaper installed on the dining room wall common to the parking structure began to peel off and was subsequently removed.
IHSC visually confirmed the presence of) mold or mold residue on the backside of the master bathroom corridor carpet, the lower portion of the master bedroom south wall, the ceiling and upper wall of the entry coat closet and a portion of the living room ceiling adjacent to the coat closet.
Water damaged drywall was also observed in the main bathroom (shower/laundry area common wall), the vaulted ceiling in the living room, a portion of the south living room interior wall and the exterior wall above and adjacent to the patio door.
No visible fungal reservoirs or apparent water damage were noted associated with the dining room wall common to the parking garage, however some efflorescence and evidence of moisture intrusion were noted along that same wall in the adjacent storage area accessed from the common corridor immediately outside the entry door to Unit 2.
IHSC utilized a Delmhorst model BD-2100 moisture meter to attempt to determine the extent of the building finishes that were moist throughout the unit. The moisture content of the fungal impacted sheetrock in the bedroom and the entry closet areas ranged form 0.2 – 0.3 % which is considered normal. Additionally the moisture content of the sheetrock measure on the walls and ceilings of unaffected areas also ranged from 0.2 – 0.3 % which is considered normal.
IHSC utilized a Mannix Model SAM990DW digital psychrometer thermo hygrometer to evaluate relative humidity within the dwelling. The relative humidity level was measured throughout the unit. The measured relative humidity within the dwelling did not exceed 20%. Humidity levels exceeding 60% and higher can potentially support active mold growth. The humidity within the dwelling appears to be adequately controlled on the day of IHSC’s site visit. Controlling the humidity in a structure is important as condensation occurs whenever the surface temperature of a material is below the dewpoint temperature of the surrounding air, water (humidity) will condense on that surface. In the normal course of a building’s function there will be surfaces, such as garage floors that during summer months have periodically cooler dewpoints than the temperature of the surrounding air. When a surface is wet (100% relative humidity) for extended periods of time the conditions are present to support mold growth if mold spores, a food source and to some degree optimum temperatures are present.
Air samples 012904-1A and 2A were collected from the bedroom and living room (respectively). Sample 012904-3A was an air sample collected from the ground level common corridor (for comparison). No outdoor comparison was collected due to the fact the fungal spore counts would likely be very low (or non-existent) due to the very cold weather and snow cover.
The fungal spore concentrations within Unit 2 ranged from 8,000 spores per cubic meter (s/m3) of air to 9,200 s/m3. Comparatively, the fungal spore concentration within the common corridor was 1,700 s/m3. Quantitatively IHSC would typically not expect indoor fungal spore concentrations to 1,000 s/m3. However, it is not uncommon to see fungal spore concentrations higher than 1,000 in buildings with electric baseboard or hydronic heat. The elevated fungal concentrations within the condominium unit compared to the common area do appear to indicate an indoor source. Refer to the attached analytical report for additional information regarding the air samples.
Additionally, the predominate spore type found in all samples were Aspergillus/Penicillium sp. Generally speaking it is normal to have the predominate species found indoors to be the same as those found outdoors. Typically in Wisconsin the predominant outdoor fungal spore types would generally include Basidiospores and Cladosporium sp. The dominance of Aspergillus/Penicillium sp., in the air samples along with the presence of Stachybortys sp., and Chaetomium sp., (fungi often associated with water damaged building materials) suggests an indoor fungal source.
Surface samples 012904-1T 2T and 3T were collected from apparent fungal growth the ceiling of the front closet, the wall of the bedroom and the master bathroom corridor carpeting (respectively). These samples confirmed the presence of Stachybortys sp., Aspergillus/Penicillium sp., Acremonium sp., Cladosporium sp., and Chaetomium sp.
Dust sample 012904-4T was collected from the air conditioning unit filter. This sample contained common outdoor fungal spores but also contained spore of Stachybotrys sp., which was found to be proliferating on building materials within the unit. Refer to the attached analytical report for additional information regarding the surface samples.
Fungi (molds) are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be controlled or avoided. Molds reproduce by means of tiny spores. The spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoor when mold spores land on surfaces containing or coated organic matter with that are wet (such as damp wood and other building materials within buildings). There are many types of mold, and few (if any) of them will grow without water or moisture. Thus the key to controlling mold is to control moisture.
The moisture impacting the bathroom carpeting and the bedroom wall is likely due to water infiltration through the foundation. The moisture impacting the living room/coat closet ceiling is likely do to water incursions from roof leaks. Prior to initiating the remediation of the fungal impacted material IHSC suggests having a moisture intrusion specialist validate this hypothesis and confirm that proper moisture control improvements have been effectively made.
The Centers for Disease Control (CDC) reports hazards presented by molds that may contain mycotoxins should be considered the same as other common molds, which can grow in homes. There is always a little mold everywhere – in the air and on many surfaces. There are very few case reports that toxic molds (those containing certain mycotoxins) inside homes can cause unique or rare, health conditions such as pulmonary hemorrhage or memory loss. According to the CDC these case reports are rare, and a causal link between the presence of the toxic mold and these conditions has not been proven.
A common-sense approach should be used for any mold contamination existing inside buildings and homes. The common health concerns from molds reported by the CDC include hay-fever like allergic symptoms. Certain individuals with chronic respiratory disease (chronic obstructive pulmonary disorder, asthma) may experience difficulty breathing. Individuals with immune suppression may be at increased risk for infection from molds. If your tenants have these conditions, a qualified medical clinician should be consulted for diagnosis and treatment. If someone believes they are ill because of exposure to mold in a building, they should consult their physician to determine the appropriate action to take. For the most part, one should take routine measures to prevent mold growth in the home and remove it when it does occur.
Currently, there are no widely used or accepted national or international standards for what represents a good or bad level of fungus in the environment. None of the publications from the CDC or the United States Environmental Protection Agency (EPA) support any specific cut-off or threshold value. Additionally there are no regulatory standards dictating how this work neither is to be done nor are there requirements dictating who can and cannot remove the mold. A building owner as well as an outside contractor can conduct this type of work.
Recommendations in this report and attached response plan are based on the New York City Department of Health and Mental Hygiene Guidelines on Assessment and Remediation of Fungi in Indoor Environments and the EPA Document 402-K-01-001, Mold Remediation in Schools and Commercial Buildings. These are the most current and applicable regulatory guidance documents available at this time.
Molds can gradually destroy the things they grow on such as wood products. Controlling moisture and eliminating mold growth can prevent damage. Again, it is crucial to any remediation project to repair the source of the water before the physical remediation of the fungi and any rebuilding the affected areas. If the source of the water is not corrected it is likely remediated fungi will return.
Basically a description of the work to be done is as follows:
- The owner shall remove movable personal items from the Unit.
- Engineering controls should be implemented to prevent remediation dust, debris and residue from entering the occupied spaces adjacent to the unit.
- Removal, handling, containerization, transportation, and disposal of moisture and microbiological containing Sheetrock in the living room ceiling, living room closet, master bathroom corridor (carpet) and wall and master bedroom south wall. Include impacted insulation materials within the exterior walls. If some Sheetrock in affected areas is left in place at least 12″ beyond the moisture mark or visible mold must be removed.
- Areas where potential water damage has occurred (living room ceiling, living room exterior wall and ding room wall) should be opened and inspected. If evidence of fungal growth is encountered in these areas the scope of work should be expanded to include these area.
- Porous surfaces with visible mold growth such wood surfaces shall be abraded (sanded or wire brushed) to remove residue and cleaned with a series of vacuuming utilizing HEPA (high efficiency filtration absolute) filtration and appropriate accessory tools such as nylon brush attachments. Porous surfaces with no visible mold growth such wood surfaces shall be cleaned with a series of HEPA vacuuming utilizing the appropriate accessory tools such as nylon brush attachments, etc. The wood surfaces should then be cleaned with a sanitizing agent dried thoroughly. Sanitizing alone may or may not sterilize the mold but it does not remove the spores from the area.
- The impacted wood surfaces should then be painted with an anti-microbial paint such as Foster 40-20 or Kilz brand paint with anti microbial properties and allowed to thoroughly allow drying.
If spore deposition throughout the unit were a concern of the Owner of the tenant it would be prudent to do a light cleaning of the unit. Such a cleaning should included and HEPA vacuuming the carpeting, furniture and other personal items. Non-porous items should also be wiped down with a cloth damped with a sanitizing solution.
Results presented are based on analysis in accordance with currently accepted industrial hygiene practices at this time and location. Other than this, no guarantee is implied or intended.
INDUSTRIAL HYGIENE SERVICES CORPORATION
Industrial Hygienist/Project Manager
Attachments, Remediation Outline
WOHL Sample Report
Unit 175, 3207 Harbor Village Road- Middleton, WISCONSIN
LIMITED MOLD EVALUATION
IHSC PROJECT NUMBER: W04-439