Sharing a Bathroom

On a cost-per-square-foot basis, the bathroom is typically the most expensive room in a house. Instead of several bedroom/bathroom suites, one bathroom designed to serve several bedrooms is a smart strategy for keeping down costs or when building a smaller house. The trick, however, is designing a bathroom that can be used comfortably by two or more people at a time.

Too often, a designer adds a second entry to a traditional bath layout with the hope that it will serve more people. Despite two entry points, the bathroom is actually less accommodating of multiple users than it would be with a single door. A person using the toilet in the middle of the night is left to wonder nervously whether she locked the other door when she hears a houseguest walking down the hall. And if she forgets to unlock the door when she’s done, that guest might not have access to the bathroom.

Typically, a bathroom like this also includes a double vanity with the aim of accommodating two people getting ready for work or school in the morning or preparing for bed in the evening. But even for spouses or partners, this arrangement is of limited use if the bathroom has an open layout.

If you want to replace several bathrooms in a floor plan with a single bathroom serving multiple bedrooms, it’s important to consider the users of the bathroom, the degree of privacy they need, and sightlines through the bathroom.

Add privacy to a shared bathroom Compartments for each bathroom function mean that a single person using the toilet won’t halt others’ morning routines. This bathroom for a small family is part of a suite away from the house’s public areas. Sometimes called a European design, the layout has separate water-closet and shower areas, and takes the place of a typical bath-and-a-half found in smaller houses. In contrast with the rest of the house, the low ceiling in the 3-ft.-wide toilet compartment creates a comfortably proportioned space. The 9-ft. ceilings in the rest of the bathroom allow light to stream through the compartments. A transom window above the shower-compartment door helps to bring natural light deep into the bathroom from the window over the shower.

How many doorways?

Deciding how the bathroom relates to the bedrooms it serves is the first order of business. Shared bathrooms usually fall into three categories: a bathroom with a single hallway entry that serves several bedrooms; a suite bathroom with a second entry from the hallway so that others can access the bathroom without traipsing through the bedroom; and a bathroom with access only from the two bedrooms that it is intended to serve.

To determine the number of entries and whether the bathroom should be tied directly to a bedroom, you first have to figure out who will use the bathroom. Will family members share it on a daily basis? Or will one family member share it with an occasional guest?

If people from more than one bedroom will be using the bathroom regularly, a single entry from the hallway often works best. Designing a suite bathroom with two entries demands greater attention to limiting sightlines within the bathroom. Even with a single entry, a bathroom is more comfortable if the sightlines are carefully planned.

Compartments add privacy

By treating the vanity as a common area and isolating the toilet and shower, two or more people can use the facilities comfortably. A toilet compartment provides privacy and a sense of security for the person in the water closet, and it allows others to use the lavatory or shower at the same time. Depending on how you add compartments and arrange different functions, up to three people can use a bathroom at once within an 8-ft. by 10-ft. plan.

If it’s not possible to fit a compartment with a door into the floor plan, carefully placed half-walls can shield the toilet and toweling-off areas to avoid embarrassing moments if someone accidentally barges in.

One efficient way of creating a bathroom that can serve several people at the same time is to adopt what some call a European design (see the drawing in “Add privacy to a shared bathroom” below). This type of bathroom has separate enclosures for the toilet and the shower, and the vanity is open to the hallway in the bedroom wing.

If the shower and the toilet area are in separate compartments, each one must be ventilated. A multiple-duct fan wired to a timer switch is an efficient way to clear the air (To learn more, read “A Buyer’s Guide to Bath Fans“).

Better sightlines improve a bath between two bedrooms This poorly planned bathroom between two bedrooms (top drawing) has a lot of wasted space. Attention to sightlines and the use of half-walls and enclosures improve the bathroom and make better use of the space, allowing for the addition of a tub. Thanks to offset doors, the bathroom fixtures don’t have to be lined up along one wall, and the hallway effect (a direct view from one bedroom to the other) is eliminated. A toilet enclosure and a half-wall at the vanity further shield views into the bathroom.

Look on the bright side

“There isn’t enough light” is the most common refrain I hear from clients about their bathrooms. Compartments and doors that divide a bathroom exacerbate the problem, so lighting strategies are important.

Adequate overhead lighting and good task lighting mounted on both sides of a mirror are essential, but nothing beats natural light. Skylights, both traditional and tubular, bring light into compartments, and I use them liberally. But I also make sure light from windows travels as far as possible. Relites—transom windows that function like clerestories—are a simple, effective way to get indirect light deep into a bathroom.

Drawings by: Russell Hamlet, AIA

From Fine Homebuilding #199