The floor and the way in
Every page says "low threshold". This is what that means in inches, and what each kind of entry takes to build.
- Curb
- The low wall at the entry that keeps water in. The plumbing code sets its depth at 2 to 9 inches, measured from the top of the curb down to the top of the drain. A lower curb is easier on knees and hips, and it asks for a more careful slope behind it.
- Shower floor (the pan)
- The code asks it to fall to the drain at 1/4 to 1/2 inch per foot. We build it over a waterproofing membrane, so water that gets through the grout still has only one place to go: the drain.
- Linear drain
- A long, narrow drain along one wall or the entry instead of a round one in the middle. The floor slopes one way, which allows large tile and makes a curbless entry practical.
- Minimum size
- Code sets the smallest shower at 900 square inches of floor and at least 30 inches across. A tub alcove is about 60 by 30 inches, twice that, so a conversion usually has room for a seat.
| Entry | Height at the entry | Who it suits | What it takes |
|---|---|---|---|
| Standard curb | A step of a few inches | Anyone who steps over it easily today | The simplest build, on any floor |
| Low beveled threshold | About 1/2 inch, sloped | Canes, walkers, a rolling shower chair | A precise slope, often a linear drain |
| Curbless | None, level with the room | Wheelchairs, and anyone planning to stay | A recessed floor (on a slab, cut concrete), a linear drain, membrane past the entry |