Case Study: Mold detection dog finds hidden contamination in multi-unit building

A Nashville property owner called Claro after noticing concerning signs in a multi-unit building. The neighboring unit had visible mold around windows, and a wall by the staircase was warped—a clear indicator of moisture intrusion behind the surface.

To locate hidden contamination that wasn't visible to the naked eye, a mold detection dog was brought in to inspect the property. These specially trained dogs can detect mold spores in wall cavities, behind baseboards, and in other concealed spaces where moisture problems often hide.

The mold detection dog marked several locations throughout the building, indicating the presence of mold that couldn't be seen. Claro focused air quality testing on these flagged areas to confirm and quantify the contamination.

The results validated what the dog detected. Multiple units showed elevated mold scores and dangerous spore counts. The upstairs hallway registered a MoldSCORE of 268 with 2,500 spores per cubic meter—nearly half the outdoor level and well into the concerning range. The living room in Unit A scored 131 with 1,200 spores. The main bedroom/bath in Unit B showed a score of 139 with 2,100 spores.

Even areas that appeared clean on the surface were contaminated. The warped staircase wall wasn't just a cosmetic issue—it was evidence of long-term moisture that had created perfect conditions for mold growth throughout the building's hidden spaces.

Claro performed comprehensive treatment of all affected units and common areas. The dry fog process reached into wall cavities, behind the warped staircase wall, around window frames, and every location the detection dog had marked.

Post-treatment testing confirmed complete remediation across all units: total culturable fungi dropped to less than 13 CFU/m³ throughout the building. The upstairs hallway that had shown 268 MoldSCORE and 2,500 spores was now clean. All units returned to safe, normal air quality levels.

The property owner was able to address the underlying moisture issues—repairing the window seals and investigating the staircase wall moisture source—knowing the mold contamination had been eliminated from all units.

This case demonstrates the value of mold detection dogs in multi-unit buildings: they find hidden contamination before it becomes visible damage, allowing property owners to address problems early and protect all tenants simultaneously.