California Residential Inspector Practice Exam

What is the minimum membrane thickness required for waterproofing exterior concrete or masonry foundation walls in severe soil-water conditions if using flexible polymer cement?

1. 30 mil

2. 45 mil

3. 60 mil

4. 75 mil

The correct answer is: 60 mil

The minimum membrane thickness required for waterproofing exterior concrete or masonry foundation walls in severe soil-water conditions, when using flexible polymer cement, is 60 mil. This specification is based on industry standards that ensure adequate protection against water ingress, which can lead to structural damage and deterioration over time. In severe soil-water conditions, the potential for hydrostatic pressure on foundation walls increases significantly, necessitating a thicker membrane to withstand these pressures and provide reliable waterproofing. A membrane of 60 mil is designed to provide sufficient durability and resistance to penetrating water. The use of flexible polymer cement also plays a crucial role as it forms a continuous barrier that can accommodate slight movements in the structure, ultimately enhancing its effectiveness in such challenging conditions. A membrane of lesser thickness may not provide the same level of protection and could lead to failures that allow moisture to penetrate the foundation, compromising the integrity of the structure.