How to detect mold behind walls?

To detect mold behind walls, look for visible signs such as water stains, discoloration, peeling or bubbling paint, and walls that appear warped or bulging. A strong musty or earthy smell can also indicate hidden mold growth. Use a moisture meter or infrared camera to find damp areas within wall spaces. Cutting a small inspection hole or using a borescope allows direct viewing of possible mold or moisture inside the wall. If mold is suspected, professional inspection and testing are recommended to confirm its presence and identify the extent of contamination safely and accurately.