Every year tremendous physical damage and financial loss to structures are caused by natural catastrophes such as hurricanes, storms and overflowing rivers, and by building related flooding from water pipes, fixtures, appliances, construction defects and maintenance issues. Water flows horizontally, downwards due to gravity, or wicks up into porous materials by capillary action. Water can cause buckling of hardwood floors, delamination of adhered materials, swelling of sub-flooring and damage to ceilings and walls.

When sudden water intrusion occurs in a building, it is usually noticed by building occupants. This offers an opportunity to correct problems and dry materials quickly. Immediate action, appropriate planning and selection of equipment, and careful monitoring are needed to protect building materials and contents from further damage caused by fungal growth. The plan should consider water pathways and concealed spaces where drying might need to be assisted. The time elapsed from the start of the event will determine the approach – removal versus drying. If moisture is allowed to remain in wall or building cavities that contain organic materials for more than a few days, hidden mold growth is likely to result. Hidden growth can be very difficult to locate once surrounding materials have dried out, and remediation of hidden growth can be very costly to remedy. An appropriate response to water entry will minimize damage and cost.

Water is the single most important factor for microbial growth in indoor environments. While water intrusion will not result in immediate mold growth, measurable growth can occur quickly. Laboratory studies have shown that fungal growth can occur within 28 hours after spores become wet. Some common species are able to grow in less than 48 hours. Even where materials are not physically wet, flooding can elevate the relative humidity which in turn can elevate the moisture on materials to a sufficient level to promote mold growth. Therefore, restorative drying contractors typically attempt to have buildings substantially dried within 48 to 72 hours of a water intrusion. Based on our field observations, mold growth on wet building materials is usually visible to the unaided eye within one week.

Immediate response will help to prevent further material saturation and damage, reduce the time needed for water extraction and drying efforts, reduce replacement of contents or building materials, minimize microbial growth and reduce the inconvenience to occupants.

Steps to Follow When Faced With a Water Loss
Rapid response - This is of utmost importance because the longer the water is present, the more spreading, wicking and damage will occur. Stop the water immediately. Identify and eliminate the source of the water. This may require assistance by professionals such as a plumber, architect or drainage contractor.

Removal of Bulk Water - Remove as much bulk water as fast as possible. Use specially designed commercial wet vacuuming equipment, water suction pumps, truckmounted carpet cleaning equipment, brooms, etc.

Assessment of Extent - It is important to determine how far water has spread horizontally and vertically and to what degree the materials are wet (moisture mapping). Use of moisture meters, infrared thermography and thermohygrometers can help identify the extent, degree and location of damp materials.

Development of Drying and/or Material Removal Plan - Initial assessment will determine the necessary equipment and drying benchmarks. Determine if drying can be performed inhouse or if outside technical drying services are required. Do you have the appropriate equipment on hand in large enough numbers to address the extent? Ongoing moisture monitoring will show if materials are getting dry according to plan or if additional equipment or material removal is necessary.

Isolation and Environmental Control - Isolation of the affected area can facilitate the drying process by reducing the air volume to be dehumidified. Isolation barriers can be created by installing polyethylene-sheeting materials from wall to wall and from floor to ceiling.

Dehumidification, Air movement and Evaporation - Dehumidification and air movement are the main methods used to dry building materials. Dehumidification reduces the moisture content of the air by removing water vapor. Once the airborne water vapor is reduced, air moving equipment will aid evaporation from exposed surfaces. Normally this is accomplished efficiently with specialized air moving equipment, referred to as air movers or blowers. Both evaporation and dehumidification are greatly enhanced by controlling the temperature in a confined environment. Higher temperature results in more rapid evaporation.

It is often necessary to open wall cavities and to remove surface treatments such as vinyl wall coverings to promote drying of concealed spaces. Windows and doors are kept closed (closed drying system) unless outdoor air conditions promote drying (open drying system).

Active vent systems are available and designed to direct airflow into wall cavities, ceiling plenums, behind cabinets and under hardwood or sub floorings. These systems may use positive or negative pressure for venting purposes.

Documentation and Environmental Monitoring - Document the water loss and the actions taken appropriately. This should include the date and time of loss, the class and category of water, the affected building materials and contents, the extent and degree of wet or damp materials. Progress evaluation is performed with moisture testing equipment for drying verification. Document your moisture measurement results. Keep a log, and review progress.

What if Mold Growth is Found?
A qualified mold investigator may perform a baseline investigation which includes moisture measurements, photo documentation, possible surface sampling and possible air sampling. Moisture measurements are performed by using hand held instruments which are pressed against building materials or by infrared cameras which detect moisture as a result of temperature differences. Surface sampling is performed by touching suspected mold growth with cellophane tape or sterile swabs and is analyzed with a microscope. Air samples are collected by hand held instruments which draw in a specific volume of air, the trapped particles from the air are also analyzed with a microscope or culturing in petri dishes. The investigator will also generate a scope of work for a remediation contractor to follow. Removal of mold contaminated building materials is the recommended course of action. This work must be performed by a trained and certified remediation contractor.

Demolition of mold-contaminated materials can create extremely high numbers of airborne spores, fragment and dust concentrations in the work area. These elevated concentration levels can pose worker exposure issues, or may result in transport to previously unaffected areas (cross contamination) and potential occupant exposures. Therefore, engineering controls and containment methods have been developed to reduce possible health effects and cross contamination issues. Containment barriers usually are constructed of 6-mil polyethylene sheeting material. The type of containment depends on the amount of mold present or anticipated and the use of the building. A warehouse may not require the same containment methods as a hospital.

Source containment may be used alone when fungal growth is limited to small visible controllable areas where no hidden mold growth is anticipated. Source containment methods create physical isolation barriers on or around moldy surfaces to prevent contaminants from becoming aerosolized. Isolation can be achieved by covering moldy surfaces with self-adhering plastic sheeting.

When larger amounts of visible mold or hidden mold growth is expected based on the analysis of data gathered in a thorough building investigation, building history and water intrusion history, the use of more extensive containment methods is recommended. However, source containment methods should also be used when remediating areas of more extensive mold growth, in conjunction with other forms of containment methods. Used in this way, source containment is a highly effective engineering control that reduces potential workers exposure and cross contamination.

Local and walk-in containments are “plastic rooms” that allows the workers to enter the containment area to perform remediation activities. Properly used in conjunction with negative air pressure, usually a HEPA- filtered air filtration device, these containments will prevent escape of contaminants and help to protect the remediation workers.

Once the remediation work is complete, but before removal of the containment, the mold investigator should return and do another visual inspection, repeat moisture measurements and air sampling in the remediated areas. This will insure the mold is removed, the area is dry and ready for reconstruction. This type of inspection is called post-remediation or clearance testing.

Who to Hire
The Institute for Inspection, Cleaning and Restoration Certification (IICRC) and Restoration Industry Association (RIA) provide a number of comprehensive training programs and certifications for technical drying contractors and mold remediation contractors. It is recommended that contractors performing technical drying in buildings should have the necessary training and experience. We recommend experts that hold at least one of these certifications: the IICRC’s Water Restoration Technician (WRT), the IICRC’s advanced designation of Applied Structural Drying (ASD), the RIA’s Water Loss Specialist (WLS), or the RIA’s Certified Restorer (CR).

Consultants conducting mold investigations must have significant experience and training in moisture and mold investigation, sampling techniques, building science, data interpretation, and remediation practice and standards. Due to the numerous two-day mold certifications without relevant experience, academic or professional training requirements, retaining professionals with reputable certifications such as CIH (Certified Industrial Hygienist) or CMC (Certified Mold Consultant) or academic training in mycology or engineering is recommended. The laboratory evaluating the air and surface samples should participate in a quality control program such as EMPAT or PAAA certifications.

Prompt and appropriate action is the key to successful management of a water loss or water intrusion which aids in preventing subsequent mold issues. Although these situations are inconvenient and can become expensive, if properly handled the cost, inconvenience, indoor air quality complaints and liability issues can be significantly minimized.

Peter Sierck, CMC, CMRS, CIEC, is an IICRC certified technician in water restoration, advanced structural drying, applied microbial remediation, and health and safety and is principal/industrial hygienist at Environmental Testing & Technology, Inc. (ET&T). Cecilia McCarthy is environmental mycologist/project manager at ET&T. They can be reached at 760.804.9400.

Back to top ▲