Case Study: Guest bedroom smell revealed construction defect and extreme mold
A Nashville homeowner noticed an odd smell coming from their guest bedroom. Then they spotted water leaking from an electrical outlet box—a clear sign something was seriously wrong behind the walls.
They called in contractors who performed moisture testing on the walls. The readings were alarmingly high. When they opened up the wall to investigate, they discovered the problem: poor construction methods had trapped moisture inside the wall cavity, creating the perfect breeding ground for mold. Before closing everything back up, they needed to know exactly what they were dealing with.
Air quality testing revealed one of the most severe mold contamination cases we've recorded. The upstairs guest room—where the leak and smell originated—showed catastrophic levels: 1.8 million spores per cubic meter.
The dominant species was Penicillium/Aspergillus at a staggering 1.7 million spores—an extraordinarily dangerous concentration. Chaetomium, a water-damage indicator mold, measured 92,000 spores. Hyphal fragments reached 7,000, confirming massive active mold growth.
Even the downstairs area, far from the source, showed elevated contamination at 4,200 spores with Penicillium/Aspergillus at 2,100 spores. The poor construction had created a hidden reservoir of mold that had been releasing spores throughout the home for an unknown period.
Given the extreme contamination levels, Claro performed an intensive whole-home treatment while the walls were still open, allowing the dry fog to reach deep into the wall cavities where the mold had established itself. The EPA-certified process eliminated contamination in both the visible damaged areas and throughout the rest of the home.
Post-treatment testing confirmed complete remediation: total culturable fungi dropped to less than 13 CFU/m³—essentially undetectable. The 1.7 million spores of Penicillium/Aspergillus were completely eliminated. All other dangerous mold species were reduced to safe, normal levels.
With the mold eliminated and the construction defects properly repaired, the contractors could close up the walls knowing the home was finally safe. The smell disappeared, and the family could use their guest room again without risk.
This case demonstrates why moisture testing and proper construction methods are critical—and why suspicious smells should never be ignored.
