According to the 2010 update to adaag the basic ada guidelines for a single user restroom are.
Minimum ada restroom dimensions.
Ideal ada bathroom guidelines for foldable l shaped shower seat is 585mm long for wide section and 405mm long for narrow section.
But technically the ada does not have a minimum space requirement for the overall size of an accessible bathroom.
Once you get accessible shower stalls for your shower mount them on your shower wall.
Ada bathroom grab bars.
Horizontal grab bars must be installed behind the toilet and on the nearest wall or partition whichever is closer.
Floor space guidelines the required minimum floor space for a handicapped accessible bathroom is 30 inches by 48 inches.
Accessible toilet stalls or compartments must have a minimum width of 60 inches and sufficient space to accommodate a wheelchair to the sides of the toilet or in front of it.
To start with the ada requires a clear floor space of at least 60 inches in diameter for the turning space within a bathroom in addition to the space taken up by the sink toilet and or shower tub.
In a corner handicap stalls require a minimum of 60 x 60 compartment and is required with a minimum door size of 32 and the maximum size and more common is the 36 door.
Ambulatory compartment stalls are 35 37 width and have a 32 door which is handicap prepped.
The ada americans with disabilities act also dictates the configuration of the fixtures in the room so they can be easily reached by wheelchair bound people.