Planning For And Preventing Water Intrusion In Buildings

water intrusionBy David Schack

Excess moisture in the built environment not only causes physical damage deleterious to buildings, it can also lead to adverse health effects and compromised indoor air quality (IAQ). These conditions will likely lead to fungal growth if not dealt with immediately and properly. Whether the cause of water intrusion is a catastrophic event, such as a building flood, or an ongoing maintenance or construction issue, a proper and timely response can save time and money.

Moisture sources that can impact buildings can be divided into two broad categories, internal and external. Internal sources of moisture include building-related systems such as plumbing and mechanical systems. External sources of moisture intrusion typically involve water or moisture entering the built environment through the building envelope such as penetrations through the roof, expansion joints, sub-slab, windows, doors, etc. Some sources of water intrusion may be attributed to construction or material defects and could have legal implications.

Regardless of the cause of the water intrusion, the resulting damage to building materials following such an event can be costly if not addressed immediately. Complications from delayed response, such as mold growth, only exacerbate the matter. Costs related to delayed or deferred remediation include expensive mold remediation, extended impact to operations, lost goodwill of employees/tenants/clients, lost time, and potential workers compensation claims.

By taking preventive steps and developing a plan for responding to moisture intrusions you can mitigate or even prevent a significant impact to operations.

water intrusion
Water is not properly draining away from the building.

Prevention and Planning

Quick steps that can be taken to help minimize the chances of water intrusions include:

  • Inspect and clean-out roof drains and gutters to insure they are working properly
  • Maintain proper sealants on roof flashings and penetrations
  • Insure that weep screeds and weep holes are working properly and as designed
  • Insure proper drainage exists around your building and that water sheds away from the building
  • Install/reinstall gaskets or sweeps on doors
  • Carefully plan construction projects, which leave the building open to the environment by using multiple weather prediction sources
  • Inspect plumbing systems for signs of damage or pending failure
  • Look for signs of water staining and investigate the cause
  • Confirm proper drainage of HVAC equipment
water instrusion
Remediation response to massive water intrusion

Have a plan to respond to water intrusions that is scalable. Large and complicated water intrusions are best left to professionals. Smaller intrusions may be handled in-house with properly trained personnel and the appropriate equipment. Here are some important considerations:

  • Develop a written response plan, train key personnel and review regularly. If an in-house response team is established, it is important to understand its limitations and establish strict criteria for calling in professional support
  • Know where to shut off water sources to the building, such as water mains, fire sprinklers, etc.
  • Identify resources such as response contractors who can respond quickly and, if possible, negotiate a contract with a response company prior to needing them. This typically insures better pricing and guarantees a response. Use contractors certified in accordance with the Institute of Inspection, Cleaning and Restoration (IICRC).
  • Understand your insurance coverage related to water intrusions. Typically, mold growth and remediation is excluded from insurance policies

Responding To Water Intrusion

water instrusion
Mold growth from water damage

It’s generally accepted that if nutrient-rich building materials (wallboard, carpeting, and other porous materials) become wetted, there is a window of 24 to 48 hours to dry the materials before mold growth can occur. Rapidly responding by initiating an immediate effort to either dry and/or remove impacted building materials is paramount to insuring that irreversible damage to building materials and subsequent mold growth does not occur.

In the event that you fall victim to water intrusion, act quickly as time is truly not on your side. In order to mitigate additional damage to the material and subsequent mold growth here are a few steps to follow:

  • Have a plan and act quickly.
  • Identify the source (different sources require different responses such as tap water, flood water, sewage, etc.), and control the source, if possible.
  • If it’s a large or complicated impact, use qualified professionals including building science professionals and response contractors to develop and implement a response. Such a response should include determining (in advance) if construction materials impacted by water contain asbestos or other regulated materials prior to disturbance.
  • Survey impacted areas with a moisture meter and infrared camera to document the extent of water intrusion to assist in managing the drying and/or remediation process.
  • Follow established criteria, such as those outlined by the IICRC and those included by the U.S. EPA in its document “Mold Remediation in Schools and Commercial Buildings”.
  • Document all activities taken to mitigate and remediate damage.
  • Investigate and repair the conditions which led to the intrusion (inspect the facility for similar conditions which led to the failure).

Special Conditions And Settings

Water intrusions originating from sewage, floodwaters, or other sources which may be otherwise contaminated necessitate a significantly more rigorous response. This is due to potential exposure to pathogens and other contaminants which can cause illness in those completing the clean-up and/or building occupants if the clean-up is not properly completed.

Meanwhile, in certain settings mold growth may warrant additional and more stringent responses with higher level of diligence based on potential significant health impacts:

  • Pharmacological compounding areas fall under very specific requirements requiring ongoing monitoring and testing for viable and non-viable particulates (mold and bacteria)
  • Mold growth within hospitals and healthcare settings represents potentially significant health risks and requires immediate, thorough and professional attention
  • Mold growth may pose a significant risk to immunocompromised individuals; therefore, areas occupied or frequented by those individuals require special attention

The prevention, planning, and proactive immediate responses to water intrusions in buildings can help avoid damaging impacts. In the least, they can prevent or significantly mitigate costs associated with unplanned events.

water instrusionSchack, vice president of Alta Environmental’s Building Science Group in Long Beach, CA, has over 26 years of experience conducting investigations and designing and overseeing remediation of environmental hazardous in the built environment. He has consulted on many high profile projects alongside forensic architects, engineers, attorneys and health specialists.


  1. I didn’t realize just how serious of a problem water intrusion can be. I like the tips you gave on preventing/ limiting intrusion on your property, one big one being well maintained gutters and excess water drainage. Keeping water away from your home can prevent big problems from happening, like foundation problems. I’ll be doing a walk through soon to look for any noticeable signs.

Comments are closed.