Mold is a big issue in older developments. Oftentimes, it’s caused by neglect of the landscaping near walls. As the property ages, the mulch rises to meet the level of the building slab. Because the contruction is wood, the moisture and mold spread in the studs and drywalls. Also people don’t monitor the sprinklers causing overwatering thus exacerbating the mold problem. Gardeners would rather over-water lest owners complain about dead plants — they don’t pay for the water.

Pinhole leaks in the walls and slab leaks are big causes of mold. Drain pipes also settle and crack causing tiny undetected leaks in the walls.

I worry about about all the condo complexes that are 30+ years old. They almost need a complete redo down to the studs. If this were Florida, the mold issue would be 10x greater.