Do you often evaluate claims involving mold or fungus growth? The causes vary, but numerous varieties of mold or fungus can emit toxic substances, making it a serious health issue.
In addition to determining the cause of mold or fungus growth, a thorough analysis should include specifications for a proper clean up to prevent recurring growth. Regrowth is a common problem, particularly in flood damaged areas.
Investigation
We investigated a home that was experiencing excessive mold growth throughout the interior. The structure had not experienced flood damage, so our task was to determine the cause of the mold and recommend corrective actions.
Our investigation included observation of the first and second floors, attic area and crawlspace. We noted a musty odor and numerous areas of mold growth on the ceilings and walls from the attic to the first floor. There was a report of a previously repaired sewer leak; a washer faucet was leaking, and the owner had placed clear plastic over the windows to help winterize the home. All were possible contributors to the home's humidity levels.
Attic
Our attic observations revealed wood blackened with mold and fungus. The moisture level of the wood trusses ranged from 20 to 30 percent. The roof deck's moisture level was 30 percent. Condensed water was dripping in several areas, but we found no roof leaks. Instead, we found the roof vents had previously been sealed with plastic. Closed or sealed vents would have caused the moisture levels to increase, but they alone could not account for the extensive problems we noted.
Furnace Equipment and Crawlspace
While we were in the interior of the home, the furnace began a normal heating cycle. Our measurements showed the home's humidity level increased by 20 percent within five minutes of the furnace's cycle. Consequently, we closely examined the furnace and surrounding crawlspace area for contributing factors.
Our observations of the furnace revealed that the galvanized duct work had rusted and fallen to the crawlspace floor. Consequently, whenever the furnace ran, it pressurized the entire crawlspace and forced the moisture-laden crawlspace air into the home's living areas.
During our observation, 60 percent of the crawlspace area was covered with 1 to 2 inches of water. There was only one crawlspace vent and no vapor retarder on the crawlspace floor.
Conclusion
The exterior grading was poor, possibly allowing snowmelt and rainfall to enter the crawlspace. The crawlspace's long-term moisture exposure caused by inadequate venting, leaking pipes and poor exterior grading allowed humid air to condense at the galvanized metal pan; this eventually caused the furnace ducts to rust. The ducts fell off into the crawlspace and allowed the humid air to enter the living areas. The installation of plastic over the windows and vents trapped the moisture in the home. The result was mold and fungal growth from the attic to the first floor. This occurred over a number of years and is not related to a single event, such as the previously repaired sewer pipe break.
Commercial dehumidifiers were needed to dry out the structure, and additional crawlspace vents were needed. Porous materials such as drywall and insulation were not salvageable. Damages could not be subrogated to the original builder or designer due to the statute of limitations.
General Notes
Always exercise caution when working in areas with mold or fungal growth; wear a respirator and other protective clothing as appropriate. Nearly all molds or fungal growth can cause allergy-like symptoms. However, some mold or fungal varieties emit toxic substances known as mycotoxins. Everyone reacts differently to these substances, and they are known to cause serious health problems.
Because of the health risk involved, it is important that you determine and address the underlying cause of mold and fungal growth. Environmental testing such as air and water sampling may be necessary. Proper remediation is key to prevent recurrence and minimize future liability risk.
Four factors are necessary for wood to decay. If any of the four factors are missing, fungus growth and decay are inhibited.
Copyright 1999 Professional Investigative Engineers. All rights reserved.
Ed holds a Bachelor of Science in Civil Engineering, and a Master of Science in Civil Engineering with an emphasis in structural engineering. He is a Certified Level 2 Infrared Thermographer, a Certified 3rd Party EIFS Inspector, and a Certified Forensic Claims Consultant (CFCC.) Ed's background includes geo-hydrology, hydrology, hydraulics, civil engineering, structural engineering and extensive work in construction forensics for building envelope sciences including asphalt work to the roof. Clients include construction companies, management companies, insurance companies, attorneys, homeowners, and homeowner associations. Ed's work has included deposition testimony, expert witness testimony, and mediations and arbitrations. He is a registered engineer in the States of Colorado, Florida, North Dakota, Wyoming, New Mexico, Texas, Nevada, Mississippi, and Nebraska. Ed's dedication to the community is demonstrated by being an active member of over 25 professional organizations. He is a published writer in "The Journal of RCI," "Building Integration Solutions," "The Forensic Engineering Task Force," "The Investigative Engineer," "The I-ENG-A Report," “Inframation, Proceedings Volumes 4, 5, 6, 7, 8,” “Colorado Claims Guide,” and "Building Integration Solutions."