A Multi-Disciplinary Approach to Mitigating Moisture Issues in Buildings

There are so many ways in which the presence of water can affect a building’s structure and function – keeping it out is a large part of the design consideration for exteriors, roofing and finishes. The most problematic damage can lead to structural integrity issues like rust, rotting, corrosion, and/or microbial growth and health issues for occupants. Surface tension and capillary action can migrate moisture away from the initial spot of intrusion, causing even greater impact.

However, despite all the best proactive measures for sealing a building and monitoring for water intrusion, it does sometimes happen! Suppose that after conducting a Property Condition Assessment as part of a commercial real estate transaction, or as a current property owner, you have found moisture somewhere on the property. Now what do you do?

A building assessment can identify indications of water intrusion, but a more thorough follow up study (also referred to as building forensics) is essential for determining exactly what the issue is, where it is, and through consultation with specialists, what the solution could be. For example, staining in tiles or building walls is a very common sign of past water damage or a current issue. But pinpointing the cause means potentially opening up crevices to figure out where the water might have migrated, if it was caused by a missing shingle, a puncture in the roofing membrane, a backup of roof drains, vegetative growth on the roof and hasn’t been cleared out, a crevice in the building allowing water in, or a myriad of other concerns. Depending on how high ground water is, foundations of buildings can also leak. For example, 75% of basement structures in the Midwest, have some level of water intrusion.

A forensics investigative team is therefore an indispensable resource for elucidating this complex engineering issue, both in terms of locating the source, as well as assessing the extent of damage and how to best remediate it. Moreover, “simple” signs of minimal moisture or leaking often belie the true extent of the damage. Two “in the field” case studies below illustrate this perfectly.

Small Drips, Big Problems: Two Case Studies My team performed a Property Condition Assessment on brand new high-end condominium high-rise in Minneapolis. The building was equipped with a rooftop pool. During the PCA, the engineering consultant noted signs of water intrusion in the lobby’s ceiling tiles, potentially signaling a roof leak. A subsequent forensics investigation methodically examined the building’s ceiling hatches and access panels – looking at moisture patterns, which ultimately tracked the path of the water to the rooftop pool. The next step was examining how the leak happened. Despite draining the pool, and its liner, the leaking continued. Next, the engineers flood tested roof deck carefully section by section and ultimately determined that the source of the leak was neither cracks in the roof deck or a pool malfunction. The culprit turned out to be a blockage in the draining system of the secondary containment (possibly incurred during the construction phase). Ultimately, the building owners had to pull out the pool, fix the drain, and build a new pool.

A multifamily property, with an exterior insulation finishing system (EFIS), brought me on as a consultant after the owner noticed moisture under the window in one of the units. A forensic investigation was required to determine why this was happening. It could have been the result of something simple, like condensation running down window from steam within the apartment, or the end result of moisture intrusion somewhere within the building. After engineers pulled some of the drywall out to look at the exterior from the window, the weep holes, which are installed in windows to drain water away from the window and keep the water out of the building, were entirely blocked. The handyman mistakenly caulked shut all of the weep holes around the building, thinking that they were holes. The retention of water within the building in all units, coupled with EFIS siding that doesn’t allow water out of the façade, created a perfect seal. Over the course of two years, water had slowly soaked through the exterior, the insulation, dry wall, and all of the building envelope materials, and rotting in 75% of the building’s wood. The repairs to the EFIS, drywall, and other structural elements ultimately cost several Million dollars to fix, and all because of a little condensation under a window!

Additional Building Repair Considerations In addition to forensic engineering investigations to determine source(s) and extent of moisture damage, restoring your property may also involve the following inter-disciplinary services:

• Roofing specialists may need to inspect, repair or replace part of your roof. A great way to proactively manage moisture issues is to invest in regular roofing maintenance, which can often catch issues early and extend the useful life of this expensive building component. Furthermore, any transactional Property Condition Assessments should focus on identifying major roofing “red flags.”
• If your mechanical, electrical, and plumbing (MEP) systems, such as the building’s HVAC, are mounted in an area impacted by water damage (such as the roof or a basement), they might need to be moved or replaced by qualified consultants. If there is corrosion of any degree, in addition to impacting critical functions, there could be potentially harmful bacteria or other biologicals distributed throughout the building, impacting Indoor Air Quality (IAQ) or creating “sick building syndrome.” Impacted components must be cleaned out or replaced.
• Whenever there are water intrusion issues, there are usually also Industrial Hygiene concerns. It may be prudent to have a certified industrial hygienist test IAQ, look for biologicals or other hazardous chemicals, and determine how best to abate them.
• A structural engineering team, in collaboration with subcontractors, may come out and repair parts of the building. In the case of building exteriors, this may involve a separate façade specialist. Water damage can significantly corrode structural steel members, or seep through the foundation and corrodes the foundation’s rebar, or spalls the concrete off entirely if it intrudes or expands within the concrete.

If you are a current building owner, investor or facility manager, do not take even the smallest signs of moisture, water intrusion, or leaks lightly. Once it is visible, it may have done a lot more damage than the surface indicates. It may not be a big issue, but it could be. Be proactive, do the forensics and figure out where the source is coming from. More importantly, be proactive in maintaining your building to prevent or minimize damage to begin with. In addition to an annual roofing inspection, consider a Facility Condition Assessment to better understand and maintain your building’s systems.

If you are conducting a Property Condition Assessment as part of a commercial real estate transaction, make sure the consultant performing the PCA is knowledgeable and experienced in the details of physical building assessments. If they don’t specialized expertise in flat roofs, or various building finishes, or recognizing corroded rebar, for example, they may not be able to recognize sophisticated signs of water damage. A firm that can bring a multi-disciplinary services approach will be able to not just recognize potential issues, but also bring the resources to mitigate the problem.