ICC Commercial Building Inspector Practice Test

How high above the maximum elevation of the groundwater table must waterproofing be installed on below-grade walls?

1. 6 inches

2. 10 inches

3. 12 inches

4. 18 inches

The correct answer is: 12 inches

Waterproofing on below-grade walls must be installed a minimum of 12 inches above the maximum elevation of the groundwater table. This requirement is based on the need to ensure that the waterproofing effectively prevents water infiltration during periods of high groundwater, which can occur during heavy rainfall or prolonged wet seasons. Setting the waterproofing at this height provides a safety buffer against potential ground-level water seepage. Proper waterproofing installation at the specified height helps mitigate risks associated with moisture intrusion, which can lead to structural damage, mold growth, and deterioration of building materials. By adhering to this standard, construction professionals can enhance the durability and longevity of below-grade spaces, keeping them safe from water-related issues.