Flooring choices significantly impact indoor air quality. Carpet, especially in basements or high-humidity areas, can act as a reservoir for dust, allergens, and mold spores. In contrast, hard flooring surfaces such as tile, engineered hardwood, or polished concrete are easier to clean and less likely to harbor contaminants.

Also examine finishes such as wallpaper, which can trap moisture and hide mold behind the surface. Ceilings should be flat and smooth where possible—textured or “popcorn” ceilings can harbor dust and are difficult to clean. Recently painted walls, especially if only partially done, may signal an attempt to hide damage.