Curbs over 9 inches are classified as what type?

Curbs over 9 inches are classified as tub units. This classification is based on the height and design of the curbs, as they serve specific functions in the context of bathroom fixtures. Tub units typically involve higher curbing to accommodate the requirements of bathtubs, which often necessitate a taller barrier to manage water retention and drainage effectively. This distinction helps ensure proper installation and functionality according to industry standards and practices, which also play a critical role in tiling and waterproofing considerations.

The other classifications, such as shower, sink, and floor units, refer to different fixtures and constructions that do not typically require the same height standards as tub units and are designed for different uses, which reinforces the specific criteria that apply to tub units.