Mold Really Is Manageable
- By Ellen Kollie
- July 1st, 2005
Left to its own devices, mold breaks down natural materials, like cellulose-based building products. That’s what the naturally occurring fungus was designed to do. Still, because mold causes damage to health and buildings, administrators want to keep it out of their campus facilities.
Chris Murray, CIH, with Morrisville, N.C.-based EI, Inc., a full-service professional environmental, safety, industrial hygiene, occupational health and engineering consulting firm, recently worked a large mold remediation case at North Carolina Central University (NCCU) in Durham. Here, he shares details of that project, as well as his expertise on mold prevention and remediation.
CPM: What was your firm’s involvement in the NCCU project?
MURRAY: Apparently, the university was aware that they had problems in a few areas. Clark Nexsen Architects was hired to investigate the problems, and we were part of that team. In July or August 2003, we did an asbestos, lead and mold survey in 10 buildings.
A mold problem was discovered in two buildings. Ironically, we were only investigating two floors in each of those two buildings — it was supposed to be a quick check of a handful of rooms. I noticed some severe problems, looked in some other rooms and made the call that it may be a bigger deal than they thought.
CPM: In which buildings was the mold found?
MURRAY: In residence halls that were built in 1998 or 1999. The names of the residence halls were New Residence One and New Residence Two — they were so new they don’t even have names.
CPM: What happened once the mold was discovered?
MURRAY: Two contractors were part of the team. One was put in Residence Hall One, and the other was put in Residence Hall Two.
EI oversaw the work in both buildings. We had a two-man crew in each building. As the contractors removed affected dry wall, we would visually inspect it and direct them to remove additional material if necessary. In some cases, we were investigating ahead of them. We made holes in the walls and the ceilings to look for condensation on the pipes. There was no other way to do it — it just becomes a destructive investigation.
We did moisture sampling throughout the buildings. Every wall and ceiling was tested, unless it was masonry. During that process, the contractor would come back after isolating an area, remove all of the gypsum, clean the space and run dehumidification equipment.
With mold, what you can visually see is the proverbial tip of the iceberg. By the time it becomes visible, it has created havoc inside a space that’s not readily visible. And that’s exactly what we found here: By the time we were identifying the problem visually, it was extensive in other areas.
CPM: What was the source of the mold?
MURRAY: There were four main issues.
First, NCCU operates an old steam boiler system that has underground steam lines running all over campus. They leak. The new buildings were tied to the system. Steam migrated up into the buildings and settled in the top-most floors. When it could rise no more, it condensated. So we found quite a bit of damage on the upper floors related to the steam.
Second, some of the individual suites had plumbing leaks around toilets.
Third, from what architects determined, the floors of the showers were constructed with improper materials, so they leaked.
Finally, there was an air conditioning issue. Some of the smaller rooms had individual air conditioning units. Imagine two units backing up, one to the other and, in between, a cavity with an air conditioning unit.
Inside the HVAC condensation pans were foam inserts that left little space for the water to collect. Also, the condensate drain line was of the wrong material and was bent or crimped at the very bottom so the condensate had no way to escape. When the condensate pan filled up, instead of draining, the water spilled over into the squirrel cage, where it got blown throughout the system. You could see mold on the ceiling near the HVAC unit vents. Plus, what didn’t spill into the squirrel cage spilled into the bottom of the unit, where there’s no collection device, ran out from underneath and got absorbed by the surrounding dry wall.
CPM: What challenges did you encounter in the remediation process?
MURRAY: The cardinal rule of any mold remediation is to stop the water source. The leaky steam system made this awkward. One problem was remediating moldy insulation in the upper floors because we couldn’t shut down the steam system. Fortunately, the temperature could be lowered to some degree. So we were taking off insulation, and the pipes are still sweating. We had to move quickly to remove the contaminated materials, do the air sampling and visual inspection, and re-insulate because the pipes were sweating the entire time.
Also, the steam proved to be challenging. The area where the steam pipes come into the buildings was bricked to eliminate free steam from migrating from the steam pits through the tunnels and into the buildings.
An interesting thing happened, too. At some point, the State of North Carolina Construction Office stepped in and managed the reconstruction. They took over the project to get it done in a more timely fashion than the private sector was offering.
CPM: In your experience, was that a lot of mold?
MURRAY: In most cases, there’s usually a primary source of moisture from a water intrusion event. One or two elements would not be unusual. To find this many problems, I would say, is very unusual.
In many cases, we recommend a proactive approach to our clients to have a plan where they routinely inspect their buildings for moisture. One opportunity may be when they do their quarterly HVAC air filter changes.
CPM: Where does the situation stand now?
MURRAY: The State of North Carolina is in litigation with the architect and the general contractor to get them to pay for portions of this. It was apparent the architectural firm knew that there were mold problems and made the university aware of them.
If you talk with someone from the university, they’ll indicate it was a construction defect. And the builder will indicate it was a maintenance issue. There seems to be plenty of fault to go around.
CPM: How can mold be prevented in new construction?
MURRAY: We have worked with several contractors who have encountered mold problems in a building before construction was even complete. They’re now engaging us to inspect a facility as specific phases are completed. We look for things like IAQ issues and mold.
We also do a final air sampling prior to the building receiving its certificate of occupancy to establish a baseline for IAQ, mold, temperature and humidity. It’s sort of a "get out of jail free" card for the builder.
CPM: What do administrators need to know about mold?
MURRAY: Be proactive. Don’t ignore the obvious. Make a concerted effort to investigate some of the well-known symptoms of a moisture intrusion problem and respond quickly and efficiently. It will ultimately save money in both construction and litigation costs.