International Compliance Association (ICA) Home Inspector Practice Exam

Which materials are most likely to develop mold when exposed to moisture?

1. Metal, glass, and plastic

2. Wool, cotton, and paper

3. Concrete, stone, and metals

4. Wood, cement, and clay

The correct answer is: Wool, cotton, and paper

Mold thrives in environments where organic materials are present, particularly when those materials are exposed to moisture. Wool, cotton, and paper are all organic substances that provide a suitable environment for mold growth. When these materials come into contact with high humidity or water, they can retain moisture, allowing mold spores to settle and begin to grow. Wool and cotton are both natural fibers that are susceptible to degradation by mold, especially in damp conditions, while paper is derived from cellulose, another organic compound that mold can easily digest. The presence of moisture not only activates mold spores but also provides the organic nutrients these microorganisms need to flourish. In contrast, materials like metal, glass, and plastic are non-porous and do not provide organic material for mold to feed on. Concrete and stone are less amenable to mold growth because, although they can retain moisture, they lack the organic components that support mold. While wood can develop mold, the specific choice of wood, cement, and clay doesn’t directly highlight the risk as clearly as the group of wool, cotton, and paper does. Thus, while some materials can be affected by mold, the ones that are most likely to develop it when exposed to moisture are indeed the organic options presented in the correct answer