Red Seal Lather (Interior Systems Mechanic) Practice Exam

When is it necessary to replace standard drywall with moisture-resistant drywall?

1. In all areas of the house

2. In areas that may be exposed to high humidity

3. In locations that never see water

4. In all ceilings

The correct answer is: In areas that may be exposed to high humidity

Moisture-resistant drywall, often referred to as green board, is specifically designed to withstand exposure to higher levels of humidity, which makes it suitable for areas where moisture is a concern. This type of drywall has a special core and backing that makes it less susceptible to mold and mildew, which can thrive in damp conditions. It is particularly necessary to use moisture-resistant drywall in areas such as bathrooms, laundry rooms, kitchens, and basements, where humidity levels can be elevated due to activities like bathing or cooking. Using standard drywall in these areas could lead to damage, compromising the integrity of the wall and posing health risks associated with mold growth. In contrast, using moisture-resistant drywall in locations that never see water or in areas of the house that do not experience highs in humidity would be unnecessary and potentially more costly than using standard drywall.