Which materials are most commonly found to harbor mold in buildings?

The materials that are most commonly found to harbor mold in buildings are wood, drywall, carpets, and insulation. These materials are particularly susceptible to mold growth primarily due to their organic nature and moisture retention properties. Wood is a natural substrate for mold since it contains cellulose, which mold thrives on, especially when exposed to damp conditions.

Drywall, also known as gypsum board, is frequently used in construction and can absorb moisture, making it an ideal environment for mold spores to settle and proliferate. Carpets provide a warm and often humid environment that is conducive to mold growth, particularly if spills or leaks occur and are not promptly addressed. Insulation can also trap moisture, especially in poorly ventilated areas, creating a breeding ground for mold.

In contrast, materials like glass and plastic, metals, ceramics, concrete, and brick are less hospitable to mold. They either do not contain organic material that mold can feed on or have surfaces that do not retain moisture as readily as the aforementioned materials. Thus, while mold can grow on virtually any material under the right conditions, the four mentioned in the correct answer are the most frequently implicated in indoor mold issues.