The process of designing a home is an evolution from macro concepts to micro solutions. At the outset, a designer focuses on a client’s patterns of movement, behavior, and other “lifestyle” input that determines the living spaces and occupant flow. But once you’ve settled on these larger issues, the real puzzle-solving begins. Now you have to stuff the client’s “can’t live without” walk-in closet next to their “must have” makeup mirror and simultaneously try to accommodate the “wouldn’t it be nice to have” Zen view window. Many times it becomes a fight for square footage and a struggle for inches.

In my 20 years of designing bathrooms, jockeying for space has occupied more time than all the other design problems combined. Perhaps it’s because many of my clients are trying to build sensible, affordable homes and their baths have to do double duty as a laundry or utility room, or both. Whatever the reason, the bathroom never seems to have quite enough space. Over the years, I’ve developed some techniques and rules of thumb to design my way out of this quandary. Here are some of the designs that resulted.

The Basic 5x7 Bath

The classic bathroom, found in millions of houses built during the post World War II building boom of the 1950s, is 5 feet wide by 7 feet long. It is 5 feet wide because that’s the length of the standard tub. It’s 7 feet long because when you add up the space required for a toilet, sink, tub, and the swing of a door, you arrive at 7 feet.

There are two versions of the minimum bath (see Figure 1, top, above). Each takes up 35 or 40 square feet (not counting the wall thickness). In the first version, the tub, toilet, and wallhung sink are all in line. The door is shown on the end of the rectangle, but it can just as easily be put on the side. The plan offers plenty of room in front of the toilet and sink, but the sink itself is small and a cabinet surround just makes the room feel smaller. The rectangular shape of the room and the optional door location make this bath easy to fit into many floor plans.

The second 5x7 bath (Figure 1, bottom, above ) offers a little more room for a sink or 24-inch vanity, but at the expense of space in front of the toilet. Also, the largest door you can fit in this plan is a 2'-4". The only place to grab some storage space in these baths is over the toilet, using open shelves or a mirrored upper cabinet.

Many clients tell me they need only a shower, and in their minds that means a 3x4-foot shower with a glass door. They think they’ll save space this way since the tub is larger. But in reality, it’s the swing of the shower door that eats up the space. So I commonly end up with a tub/shower, usually with a sliding door.

Desperation Baths

In really tight spots, I’ve had to come up with even smaller designs. Using a shower with a curtain instead of a door it’s possible to trim off 5 square feet and get the room down to 30 square feet overall.

The top bath in Figure 2 above uses a 36-inch corner shower unit. This plan also requires a wall-hung sink, and the door swing intrudes into the space in front of the toilet. Although the design is a seemingly efficient square, for some reason I can’t explain it almost never fits comfortably into my floor plans.

The bottom bath in Figure 2 above is a series of compromises. A wall-hung sink is all that fits, the bath door itself has to swing out, and, for lack of swing clearance, the shower can only have a curtain. There is, however, room for an extravagant set of shelving next to the toilet.

Minimal Baths With Utilities

Just designing a small, efficient bath would be too easy. Several of my jobs have required that the “core” plumbing and heating utilities and the washer and dryer also be included in the space. These are good goals for decreasing plumbing costs and saving space, but I used up a lot of erasers arriving at the designs.

The bath shown at the top in Figure 3 (above) has a long and a short version. The short version is a full bath with washer/dryer and room for the water heater. There is also space for cabinets over the washer/dryer and shelving over the toilet.

Lengthening the room stretches the vanity so that it can double as a folding table for laundry, or you can add a second sink. The opposite wall has space for a floor-to-ceiling linen closet. The other bath/utility core design (Figure 3, bottom, above) has washer/dryer, water heater, and furnace as well as a full bath with linen closet, all tucked into 82 square feet. Cabinets above the washer/dryer and shelves over the toilet add even more storage.

A third configuration of baths with integrated utilities was designed for a duplex on a long narrow lot (Figure 4 , above). I include it because it combines two bathrooms and a utility room into a spacesaving unit that can be adapted to townhouses or other narrow-lot designs. Note how two bedrooms share one bath, while the master bedroom uses the second. This is a plumber’s dream because all the piping is tightly arranged.

Attic Baths

Cost-conscious homeowners are always looking for opportunities to use attic spaces, so I’ve included a couple of second-story or attic baths (Figure 5 , below). These are especially challenging because a third dimension — height — further constrains movement in the room.

The good news is that there’s only one number you need to remember: 6 feet. The top of a mirror should be a minimum of 6 feet, the lowest wall in a shower should be 6 feet (unless you provide an operable skylight like we did in one house), and the floor-to-ceiling height above the midpoint of the toilet must be at least 6 feet (for reasons obvious to tall men).