THE COHEN GROUP
  Environmental Health & Safety Consulting Services

The Cohen Group Newsletter - Volume 6  Issue 3, Article 3.  August, 2004

Julie V. Wellings, CIH

There is much discussion these days over the potential hazard of mold in buildings. What these discussions have brought to light is the wide range of conditions, occupant perceptions and building manager or consultant responses associated with water-intrusion and mold-growth in buildings. For example, most instances of water intrusion and mold growth in well managed buildings are limited to a single location and event affecting a small surface area. In poorly managed buildings, however, deferred maintenance can result in water intrusion and mold growth from many sources over an extended duration affecting a large surface area. Occupant perception and reaction to the presence of mold is generally based more on information in the media than in the scientific literature.

The following "case studies" are presented for illustration of various conditions, responses and outcomes related to water-intrusion and mold growth in buildings:

· A recently-acquired building in apparently good condition was beset with a localized moisture and mold problem when a plumbing leak occurred over a weekend. Remediation was promptly initiated upon learning of the leak, including drying and removal of moisture-impacted materials. During the initial remediation process, evidence of previous unrelated water intrusion and mold growth was discovered when the vinyl wall covering was removed. Moldy odors (indicative of active mold growth) became apparent only when building ventilation was modified for the initial remediation effort. Additional removal of vinyl wall covering and underlying drywall revealed the probable moisture sources, including rainwater (leakage around windows) and domestic water (leakage and spillover from plumbing fixtures). Ultimately, in order to restore the affected area to a satisfactory condition, removal and replacement of all affected wall and ceiling materials was required.

· Particularly heavy seasonal rains impacted a newly-constructed medical office, and some water intrusion and mold growth occurred. Remediation contractors were retained to repair leaks in the building envelope and remove mold-impacted materials. Following completion of remediation work, the building owner’s mold consultant performed "clearance" inspections and monitoring, and concluded that the remediation work had been satisfactorily completed. However, the major tenant hired their own mold consultant who interpreted the monitoring results differently and concluded that "hidden mold" might be present. Although further evaluation of the building discounted the likelihood of significant "hidden mold", the building occupants were left with the perception that the building was still "mold-impacted".

· A new office building was subjected to winter storms, resulting in intrusion of rainwater at improperly-sealed window openings. Building management, being well aware of the potential problems, acted quickly. Within 24 hours, the affected area was cleared of furnishings, the carpeting was pulled back, and remediation contractors were called in. While one contractor was repairing leaks around window openings, the other contractor extracted water from floors and carpeting, removed impacted drywall and dried the interior area using dehumidifiers. When the interior area was thoroughly dry, replacement of drywall, carpeting and furnishings was accomplished. Inspection of the wall cavity and monitoring for airborne mold indicated that, due to timely remediation, no detectable mold growth or airborne mold release had occurred.

These case studies represent just a few of the many variables related to water-intrusion and mold growth in buildings. They do, however, point to key steps that a building manager can take to minimize water- and mold-related problems:

In new building construction, place particular emphasis on the construction and sealing of the building envelope, i.e. installation of roofing, exterior wall systems, windows, doors and other fixtures.

Prior to purchase or lease of older buildings, investigate maintenance history and previous water-intrusion events.

Initiate remediation of moisture-impacted areas as soon as possible following a water intrusion event. It is best if the work can be started within 24-hours of the event. Carpeting should be extracted and pulled back to minimize moisture retention and mold growth. Significantly-impacted porous cellulose-based materials that are likely to support mold growth (such as drywall paper and ceiling tiles) should be removed and discarded. Dehumidifiers should be used to dry remaining building materials.

Evaluate and document satisfactory completion of mold remediation work through a combination of inspection, moisture testing, surface sampling and air monitoring, as appropriate for the building condition and scope of remediation work. Following remediation, provide tenants with a report of findings, summarizing and documenting the successful completion of the work.

It is becoming common for property owners and managers as well as general contractors and developers to establish a "mold response plan" in advance of water-intrusion and/or mold growth problems so that appropriate action can be promptly taken. Please call us if you would like to discuss the potential scope and benefits of such a plan.