To what height must bathroom walls and partitions have a smooth, hard, nonabsorbent surface?

Bathroom walls and partitions are specified to have a smooth, hard, nonabsorbent surface up to 4 feet in height to ensure hygiene and ease of maintenance. This height is critical because it provides protection against moisture and potential damage from splashes and spills that occur in such environments. A nonabsorbent surface helps prevent mold growth and makes cleaning more effective, which is essential in a sanitary space like a bathroom.

This standard is often enforced in building codes to maintain health and safety within commercial buildings, ensuring that frequently exposed areas can withstand the wear and tear associated with high humidity and frequent cleaning. A lower height would not adequately protect the walls from exposure, while a higher specification could be unnecessarily costly and unattainable in some designs. Thus, the requirement for a smooth, hard, nonabsorbent surface up to 4 feet ensures a balance between durability, hygiene, and practicality.