Hurricanes, tropical storms, floods. Unfortunately many of us have witnessed the havoc and devastation that unwanted water causes to a building or home, not to mention the emotional stress left in the aftermath. But cumulative secondary damage conditions – including adverse health effects from being exposed to compromised indoor air quality and mold – can occur when stagnant water is not dealt with in a timely manner (typically 48 to 72 hours upon discovery). Delays in responding to water events can also cause    business interruption and deplete the goodwill of employees and occupants.

Whether the cause of damages is a one-time catastrophic event (i.e., hurricane) or an ongoing hidden slow leak, a moisture intrusion plan can be a vital tool to help reduce the overall risks and save time and money.

Moisture Sources

The cause of moisture intrusion into a structure can be obvious, hidden, or complex, and may be from internal or external moisture sources. Internal sources can be a plumbing leak, condensation, or excess steam from kitchen operations. External intrusion can come from openings and unsealed wall penetrations, expansion joints, windows, doors, roofs, and foundation cracks. Sources can be related to the original construction, failed product issues, poor workmanship, or deferred maintenance.

Regardless of how moisture enters interior spaces, a fast turn-around response is needed by experienced professionals to permanently stop and repair issues before mold growth can occur (within 48-72 hours).

Development of a Moisture Plan

The moisture plan is a “living–breathing” document that should be updated and moved in tandem with the  dynamic nature of the building’s life cycle. The plan outlines the procedures and the ‘”what-ifs” on how to    prevent, respond to, and document an event. All responsible parties need to read it, understand it, sign-off on it, and know where to find it in case of emergency.

Design or Pre-Construction Phase

Prevention of moisture intrusion starts with proper design and review of contractual provisions to establish overall responsibility, communication, response, training, and documentation. Not only does the general   contractor have overall responsibility, but all retained subcontractors must be on board, be trained, and do their part to prevent or minimize water intrusion. These responsibilities should not only be spelled out in the contract agreements between parties, but also made part of the moisture intrusion plan, so that all  responsible parties are part of the water team before they even step foot on-site. Communication is the key for successful implementation of the plan.

Design engineers and architects have a big role to play as the first line of defense against moisture intrusion – by the professional choices they make in specifying water-friendly resistant building products; façade and building envelope, ventilation, and waterproofing materials; condensate collection design, drainage, landscaping, and irrigation; and roofing materials, to name just a few. Pre-site analysis, constructability review, and assessment are all tools to help prevent water intrusion into a building.

Today, design professionals are more aware than before about how moisture can affect building health. Designers can choose “smart” devices and sensors – connecting the building through the “Internet of Things” to monitor the building’s health in real-time without requiring human-to-human or human-to-computer interaction.

For example, low-cost wireless sensors can be pre-placed in building cavities at high-risk areas in the structure during construction (such as humidity, moisture, CO₂, and temperature transducers). These devices can communicate with a host computer in a “plug and play” fashion that converts data to protocol that makes it available locally or via the cloud. Smart repeaters can be used to increase range and allow data to be transmitted over a large distance or where obstructions occur. Contact self-powered mini-sensors, powered by ambient room light, can be used to detect open or closed doors and windows around the building or determine desk occupancy by attaching small wireless boxes that stick to the underside of a desk or table to monitor the presence of occupants in real-time.

Design of certain facilities – such as pharmacological compound labs, hospitals, healthcare facilities, and nursing homes – may require additional planning, since they can pose a higher risk to immunocompromised individuals if mold amplification occurs due to water intrusion.

Construction Phase

Lots of things can go wrong during the construction phase. The construction site is a busy place and is sometimes referred to as “controlled chaos”. Unexpected weather can cause significant water damage during construction, if proper planning is not undertaken beforehand. Site operations must be performed and sequenced with care to ensure that water infiltration is minimized.

Key prevention procedures during construction include:

• Sequence delivery of moisture-sensitive building materials to minimize on-site storage and weather damage.
• Moisture test semi-porous and porous building materials for moisture content at delivery.
• Wrap and anchor temporary all-season weather protection around building during construction to prevent water   intrusion.
• Seal and inspect all building penetrations at the end of the construction day.
• Construct building envelope/exterior walls and roof prior to construction of interior portions that may be less water-resistant.
• Review water-sensitive construction operations (i.e., fireproofing and lightweight concrete applications) to assure proper air circulation and drying is employed to avoid subsequent mold growth on water-sensitive building materials.
• Conduct routine daily/weekly water intrusion inspections and report water events immediately – with corrective action within 48-72 hours.
• Make substantial completion documents, sign-offs, warranties, equipment manuals, and operations & maintenance (O&M) instructions part of the moisture intrusion plan.

Responding to a Moisture Intrusion Event and Long-Term O&M

Given proper temperature, humidity and nutrients and in the presence of a water source, mold amplification can occur within 48-72 hours. Since water is the rate-limiting step in mold growth, if water is controlled, mold cannot amplify. So stop the water and mold growth cannot occur.

Key water responses and long-term O&M tasks include:

• Inspect, maintain and replace weatherproof sealants and flashing around wall penetrations.
• Maintain roof drains and clean out gutters periodically.
• Inspect weep holes at the bottom of building envelope drainage.
• Review topography near building perimeters to make sure soil slope away from foundation walls.
• Inspect plumbing and HVAC systems for leaks and condensation.
• Use wet vacuum, drying, and ventilation methods to collect excess water and dry building materials if a water event occurs.
• Use heaters and directional blowers to assist in the drying process.
• Remove wet or moldy materials from the building; seal and dispose in 6-mil polyethylene bags.
• Follow all IICRC (Institute of Inspection, Cleaning and Restoration Certification) water industry drying guidelines, if a water event occurs.
• Conduct mold cleanup in accordance with appropriate federal, state and local guidance documents and recommendations.

Conclusion

Moisture intrusion plans should be thought of as a proactive, “living–breathing” document that addresses the “what ifs” when dealing with internal and external sources of moisture. The plan needs to be written early on and updated throughout the building lifecycle – from design through construction to long-term O&M. Having a moisture intrusion plan can prevent or significantly mitigate costs, bodily injury, and business interruption from unplanned events. It may also be  required or be part of the underwriting submission to obtain or renew environmental liability insurance for the building.

HETI…Helping Control Moisture Intrusion and Mold Damage

HETI can assist building owners/managers, occupants, and their insurance carriers in both the areas of  moisture intrusion/mold prevention and response. We can help in the development of effective water management plans, ventilation and indoor air quality assessments, along with cost-effective and feasible solutions should a moisture intrusion/mold event occur.

References:

Mold Remediation in Schools and Commercial Buildings, United States Environmental Protection Agency (EPA 402-K-01-001), September 2008

Guidelines on Assessment and Remediation of Fungi in Indoor Environments, NYC Department of Health and Mental Hygiene, November 2008

Bioaerosols: Assessment and Control, American Conference of Governmental Industrial Hygienists, 1999