How to Prevent Mold in Commercial Buildings: 10 Things Facility Teams Should Know

Chris White • July 17, 2026

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Imagine you’re sitting in your office when you notice a drip-drip-drip. You grab the trash can, put it under the leak, and think, problem solved.


Or is it?


Does that water touch anything that can support mold growth, like gypsum board or ceiling tile? Do you notice odors after it rains? Do you see dark, fuzzy growth around the leak or near air conditioning vents?


Mold might not be the end-all bad stuff some folks make it out to be. But if you or someone else notices it, it is an aggravation at the very least. It takes time away from other work, raises questions about the building, and causes pain for the people responsible for the facility.


So the practical goal is simple. Address the mold, clean up the affected area, and figure out what allowed the moisture to get there so the same problem does not keep coming back.


Recurring mold often points to two separate issues. You need to address the mold itself, along with the moisture conditions that allowed it to grow. If moisture continues to reach the same materials, remediation may provide only a temporary solution.


Why Does Mold Keep Coming Back in Commercial Buildings?

Mold commonly returns because the visible growth was addressed, but the moisture condition that supported it remained. The source may be obvious, such as a roof or plumbing leak. Sometimes it takes more work to understand what is happening.


In commercial and institutional buildings, moisture can also be related to:

  • humid outdoor air entering cooled spaces
  • condensation on ductwork or piping
  • damaged or missing insulation
  • HVAC operation
  • building pressure
  • exterior wall or window leakage
  • storm damage
  • prolonged HVAC shutdowns
  • recurring maintenance conditions


That dripping ceiling tile tells you something useful. It tells you where some of the water ended up.

It does not necessarily tell you where the water started.


That is why mold and moisture consulting may involve looking beyond the visible growth and evaluating the building conditions that could be contributing to it.

What Are 10 Things Facility Managers Should Know About Mold?

The best way to reduce recurring mold problems is to control the moisture that allows mold to grow. I've probably said this more times than I can count: control the moisture.


There is no practical way to eliminate every mold spore from an indoor environment. The more useful approach is to understand where moisture is coming from, address affected materials, and reduce the conditions that allow the same problem to develop again. Here are 10 things to keep in mind.


1. Mold can affect building occupants.

Potential health effects associated with mold exposure may include allergic reactions, asthma, and other respiratory complaints. Those concerns are important, but they are not the only reason a commercial owner needs to pay attention.


Even when the health effects aren't the issue, mold can still be an aggravation. It can generate occupant complaints, take staff time, disrupt normal building operations, and raise questions about why the area became wet in the first place.


Mold can also affect how a space is used, generate occupant complaints, require staff time, and disrupt normal building operations.


2. You cannot practically eliminate every mold spore indoors.

Mold spores are part of the environment. Trying to eliminate all of them is not a realistic mold-control strategy.


Controlling moisture is the more practical objective.


3. Address the mold and the moisture.

Cleaning mold-affected material may be necessary, but it does not automatically address the condition that allowed the growth to develop.


If the moisture source remains, the same area may need attention again.


4. Fix water leaks and understand where the water traveled.

Roof leaks, plumbing problems, exterior water intrusion, and other sources of unwanted moisture can create conditions that support mold growth. I've seen plenty of situations where the place you see the water is not where the water started.


The visible leak may only be the beginning of the investigation. Water can move through ceilings, walls, insulation, and other building materials before it becomes visible in an occupied space. That ceiling tile may tell you where the water ended up. It may not tell you where the problem began.


5. Pay attention to indoor humidity.

A commercial building can have a moisture problem without having a traditional water leak. In Louisiana, we don't get much of a break from humidity.


Louisiana buildings spend much of the year cooling indoor spaces while outdoor air remains hot and humid. When humid air reaches cold surfaces or mechanical components, condensation can develop.


6. Dry wet materials promptly.

Address damp building materials and furnishings promptly. The original guidance recommends cleaning and drying wet materials within approximately 24 to 48 hours.


The longer moisture remains in ceiling tile, gypsum board, insulation, carpet, or other materials, the greater the opportunity for additional damage and microbial growth.

 

7. Clean appropriate hard surfaces.

For suitable hard surfaces, you can often clean mold with water and detergent, followed by thorough drying. That still leaves an important question. Why was the surface wet in the first place?


Cleaning addresses what is there today. Understanding the moisture helps address what could happen tomorrow.


8. Look for condensation.

Condensation is moisture too. Cold ductwork, piping, HVAC components, building-envelope conditions, or air movement can create recurring dampness even without a roof or plumbing leak.


This is one reason HVAC systems and exterior building assemblies sometimes need to be considered together.


9. Think about the materials used in areas with recurring moisture.

Carpet and other moisture-sensitive materials may not be appropriate in locations where damp conditions repeatedly occur.


If the same material has been replaced several times in the same area, that repair history is useful information. It may tell the facility team the problem is bigger than the material being replaced.


10. Keep coming back to the moisture source.

This one is worth repeating. If the mold keeps coming back, look for the moisture.


A facility team can replace ceiling tiles, clean surfaces, collect samples, call contractors, and prepare reports. That is a lot of activity. But if no one answers why the area keeps getting wet, the building may continue cycling through the same problem.


What Should a Facility Team Do When Mold Is Found?

Start by handling the immediate condition, then look for the reason it developed.


The immediate response may involve:

  • addressing active water
  • evaluating affected materials
  • cleaning or removing materials as appropriate
  • drying the area
  • documenting what was found


Once you control the immediate issue, ask the bigger question. Why did this happen here? The answer may involve building history, moisture measurements, HVAC information, pressure relationships, roof or exterior wall conditions, previous repairs, and targeted sampling when it helps answer a specific question.


For commercial building owners and property managers, the goal isn't just to get one room back into service. It is understanding whether the condition points to a larger building problem that could affect other areas.


Why Does Building History Matter When Investigating Mold?

One of the things I've learned from working on buildings is that the people who work in them every day often know more about the history of a problem than you can learn during a single site visit. Ask them questions.


Does the odor appear after heavy rain? Does the same corridor smell musty every summer? Did the staining begin after an HVAC problem? Has that ceiling tile been replaced three times already? Those details matter because buildings have histories.


A facility manager, maintenance technician, or custodian may recognize patterns that are not obvious to someone seeing the building for the first time. That information can help focus the evaluation on the conditions most likely to be connected.

This can be particularly important in schools and educational facilities, where maintenance teams may have years of firsthand knowledge about recurring roof leaks, humidity conditions, HVAC problems, and spaces that have required repeated work.


When Is Mold Testing Useful?

Testing is most useful when it is tied to a specific question. Collecting samples because “we need to test for mold” may not tell the owner what is actually causing the problem.


Before collecting a sample, I like to ask a simple question: What are we trying to find out? Are you trying to understand whether visible material is mold? Are you evaluating an affected area? Are you trying to understand conditions in an occupied space? Are you investigating why the same problem keeps returning? Those are different questions, and they may call for different approaches.


The important thing is that the information collected helps the owner decide what to do next.


How Can Commercial Buildings Reduce Recurring Mold Problems?

A proactive approach starts by recognizing moisture conditions before visible mold becomes the first warning sign.


Facility teams can track:

  • recurring roof leaks
  • plumbing failures
  • condensation
  • HVAC shutdowns
  • elevated humidity
  • storm-related water entry
  • repeated ceiling-tile replacement
  • musty odors
  • exterior wall or window leakage


That history becomes more useful when the facility treats these events as connected information rather than unrelated maintenance calls.


In a large commercial building, hotel, school, hospital, or multi-building campus, a recurring moisture condition can affect far more than one room. It can affect operations, maintenance budgets, occupant concerns, and capital planning.


When Does a Mold Problem Need a Deeper Building Evaluation?

A deeper evaluation may be appropriate when the problem keeps returning, affects multiple areas, or has no obvious moisture source.


At that point, looking at the building as a system may provide more useful information than focusing only on the affected material.


The exterior enclosure controls water and affects air movement. HVAC systems influence temperature, relative humidity, airflow, and pressure. These systems can interact in ways that aren't always obvious from the location of a stain or patch of mold.


Wynn L. White Consulting Engineers approaches mold and moisture problems by working through practical questions. What do we know about the building? What does its history tell us? What conditions are present? What information is missing? What does the owner need to know before deciding what to do next?


A longer report is not automatically a better report. The information needs to help someone make a decision.


How Can Facility Teams Be More Proactive About Mold?

Don't wait for visible mold to be the first sign of a moisture problem. Recurring condensation, staining, unusual odors, roof leaks, plumbing problems, high humidity, and repeated repairs can all provide earlier clues.


Wynn White, P.E., and Chris White, P.E., developed the Mold Prevention Guide in New & Existing Buildings around many of the same conditions they have encountered in commercial and institutional facilities.


The guide focuses on recognizing moisture conditions, understanding how problems develop, and thinking more proactively about preventing the same issue from returning.


What Is the Bottom Line on Mold Prevention?

Address the mold, but keep looking for the moisture. Mold often becomes visible long after the problem started. Use the building’s history, listen to the facility staff, and consider how the enclosure and mechanical systems may be interacting.


That gives the owner better information for deciding what to repair, what to monitor, and what needs a closer look. And if you find yourself putting a trash can under the same leak for the third time, it may be time to ask a different question: Why does this keep happening?

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We have had some questions on cleaning and disinfecting facilities for coronavirus (COVID-19). We have worked to prepare specifications building owners can give contractors to clean and disinfect facilities for coronavirus. In particular, these specifications include cleaning and disinfecting HVAC systems for coronavirus. Obviously, the coronavirus pandemic is unlike anything we’ve experienced. This is not like a flood, hurricane, earthquake, or any other natural disaster we’ve faced. The other virus scares we’ve had in recent years haven’t come close to this. And since coronavirus is invisible and very difficult to detect (at least in comparison to the kind of environmental sampling we typically do), cleaning and disinfecting facilities for coronavirus is not like mold remediation or asbestos abatement. Instead of quickly firing out specifications for cleaning and disinfecting for coronavirus, Wynn and I spent a good bit of time thinking through the process, including surface cleaning and disinfection, HVAC system cleaning and disinfection, and finally, how to verify successful cleaning and disinfection of coronavirus. So it’s taken us some time to get the specifications together. Add to that what we don’t know about coronavirus: how long it can survive on different surfaces and in certain conditions, how temperature and relative humidity affect coronavirus, on and on. We’ve done our best to come up with a thorough cleaning and disinfection specification, but something pretty much any restoration or environmental contractor can execute. Compared to our other specifications, like for mold and asbestos, these specifications are much shorter, while still containing good information to protect the contractor, building occupants, and get the job done. We got to thinking about the places or surfaces where coronavirus could survive, as well as the risk for building occupants from high touch surfaces or ways to spread coronavirus through the air. Surface cleaning and disinfection for coronavirus is obvious. But there could be areas we haven’t yet considered. It got us to thinking about a place or system every building has: the HVAC ductwork and coils. It turns out coronavirus likes cold, wet places. Well, what’s one place that’s cold and wet in our buildings? That’s right – the air conditioner coil, or HVAC system coil. Whatever term you use. When we run our air conditioners, the HVAC coil stays cold and wet. Since coronavirus can get into the air, it can get into the HVAC system, and from there, to the coil. So there’s a ready made spot for coronavirus to survive, even if the building is totally abandoned. Unless we totally abandon a building and shut off the air conditioners, there’s a chance coronavirus could survive past what we think is a safe period. Here’s a quick rundown of what’s included in the specifications, and our thinking for how to go about cleaning and disinfecting facilities for coronavirus: First, the specifications require a thorough cleaning and disinfection of surfaces and materials. No magic here – a thorough cleaning using one of the materials listed with the EPA for cleaning and disinfecting coronavirus . Second, building owners may want to consider cleaning and disinfecting HVAC systems for coronavirus. This includes the ductwork and the coils. For other microbiological contaminants like mold, often duct and coil cleaning is not necessary. There’s also the inconvenient fact that as soon as you open the building and turn the HVAC system back on, mold gets back into the ductwork and rest of the HVAC system since mold is everywhere. 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In case you missed it, here’s a link to the Indoor Environmental Quality Podcast Episode 8 where I cover Ready.gov and OSHA information on coronavirus. If you’d like more information, email me . Or visit our website www.wynnwhite.com or you can find me on Twitter and Instagram: @chriswhitepe The Indoor Environmental Quality Podcast is available in iTunes (if you’re still running the old school iTunes application!), Apple Podcasts app, Google Play, iHeart Radio, and Spotify.
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