There are several ways to Half the bathroom floor plan by carving out space from your existing floor plan, depending on the layout of your house. I've presented three options that have worked for my clients: a bathroom hidden beneath a stairwell, one carved from a garage, and another nestled inside a gabled attic dormer. A half bathroom floor plan requires a toilet, a sink, and a mirror. It's nice to have an under-sink cabinet or another storage area for extra tissue paper, hand towels, and soap, but these items can be kept elsewhere if space is limited.