When is a crawl space considered a basement?

A crawl space is considered a basement under specific conditions that pertain to its height and usage. The consideration of both height and the presence of certain mechanical systems or occupancy is essential in delineating between a crawl space and a basement.

The criteria set forth in the correct answer highlight that a crawl space that exceeds a height of 1800mm (or approximately 6 feet) is often classified as a basement due to the potential for human occupancy and use. Additionally, the presence of mechanical ducts or piping indicates that the space is designed for more than mere storage; it may serve as a functional part of the building’s infrastructure, further justifying its classification as a basement.

In essence, both the height and the presence of systems that support human activity or environment management within the space contribute to its classification. Thus, both factors from the correct answer are significant in defining when a crawl space transitions into the category of a basement.