When is it required to damp proof floor and walls?

Damp proofing of floors and walls is essential in construction and is particularly necessary to protect structures from moisture that can lead to damage and deterioration. The correct answer highlights that damp proofing is required when ground water is above 6 inches.

When ground water levels rise above a certain threshold, typically considered to be 6 inches in many building codes and practices, there is a significant risk of water intrusion into the building. This moisture can cause several issues, including mold growth, structural damage, and compromised integrity of finishes and insulation within the walls and flooring.

The choice indicating requirements when consistently below ground or when below the ground water level doesn't recognize the critical threshold that initiates concerns for damp proofing. Simply stating that damp proofing is always required does not reflect the specific conditions under which it becomes imperative; rather, it is contingent on the prevailing ground water levels. Thus, knowing that damp proofing is necessary when the ground water exceeds 6 inches is vital for ensuring the longevity and safety of residential structures.