Clients who find it difficult to maneuver over a typical shower threshold or need to wheel into a shower will benefit from the installation of a curbless or no-threshold shower opening. If your client is considering a no-threshold or curbless shower, there are many special floor construction features that must be considered. With any shower, a major design consideration is to keep water contained so it does not seep into the subfloor and cause damage. Because no-threshold showers may not have a door, designing these showers such that water will not splash out the opening is an additional design challenge. The design components important for keeping water in the shower space include the size of the shower, the location of the handheld showerhead, the slope of the floor, and the drain location. You will find more details about no-threshold showers in chapter 8, "Accessibility in Practice." You can also reference a publication from North Carolina State University titled Curbless Showers: An Installation Guide, which is available on the companion website to
this book (www. wiley. com/go/bathplanning) and online at www. ncsu. edu/ncsu/design/cud/ pubs_p/docs/Curbless. pdf.
A whirlpool, jetted tub, or soak tub can exert a great deal of pressure on a floor because of their weight when filled with water and people. In new construction, extra supports are fairly easy to add. In older homes, however, a careful evaluation of the floor structure is needed. Older floors were typically not built to hold these oversized tubs; therefore, reinforcing the floor is necessary (see Figure 2.2). Stripping the floor down to the joists will help clarify if the joists are large enough and spaced appropriately with enough support to hold these heavy tubs. If they are not, more support will need to be added.