The Illustrated Rules of Good Bathroom Design

1. Clear openings of doorways with swinging doors shall be measured between the face of the door and stop, with the door open 90 degrees. (ANSI 404.2.3) If the door can open a minimum of 93 degrees, the handle may be disregarded in measuring the opening.
2. When a passage exceeds 24" in depth, the minimum clear opening increases to 36". (ANSI A117.1 404)

1. The International Residential Code is silent as to door widths and heights of interior doors. Many communities have, however, supplemented the basic code by requiring a minimum 30" door opening in most rooms, 24" for bathrooms, at least one 36" exterior door, and a minimum door height of 6'-8" (80"). For bathrooms complying with the Americans with Disabilities Act (ADA), the clear door opening must be 32" wide with the door fully open which usually requires a 34" wide door at a minimum.
2. Standard door widths include 18", 20", 24", 28", 30", 32" and 36" doors. Any other width and any door wider than 36" is generally made as a custom door.
3. To achieve a clear opening, the door size must ordinarily be at least 2" larger. For example, a 32" clear opening requires a 34" door, and a 36" clear opening requires a 38" door.
4. Since a 34" (2-10) interior door is typically a special order custom door, this standard is usually met with a 36" (3-0) standard door. A 36" opening for a narrow passageway requires a 38" door to meet the requirements of ANSI A117.1 404. These are not available except as custom doors – so narrow passageways should be avoided where possible.
5. In a bathroom remodel, codes generally do not require an existing door to comply with current minimum opening widths but if the door is moved as part of the bath remodel, then most jurisdictions will require that current code minimum opening standards be met.

1. The general code requirement is that ceilings be at least 90" (7'-6") high but an exception is made for bathrooms that are required to be only 80" (6'-8") high. In any place where a person cannot walk, the ceiling may slope or be dropped down to as low as 60" (5'-0"), and most code officials will allow an even lower drop, especially in bathroom remodels, if it is safe and reasonable under the circumstances.
2. The requirement that a shower be at least 30" x 30" x 80" at the shower head is merely practical. Much smaller and the average person would not fit. It is difficult to find a pre-made shower cabinet this small. The usual minimum size is 32" x 32".
3. The minimum height of 80" (6'-8") "over the fixture" includes the required minimum clear floor space in front of the fixture, which must also have a minimum height of 80" (6'-8"). See Guideline 4.
4. This Guideline must be coordinated with Guideline 9.
5. In remodeling bathrooms, this Guideline will have the most impact on bathroom remodels in basements, attics or garrets were ducting or the slope of the roof may reduce the ceiling height over some part of the remodeled bath.

1. The minimum distance from the centerline of the lavatory to a wall is 15". (IPC 405.3.1)

2. The minimum distance between a wall and the edge of a free-standing or wall-hung lavatory is 4". (IRC R 307.2)

1. A pedestal or wall-mounted lavatory must meet both of the Building Code Re­quire­ments.
2. a. The center of the lavatory must be at least 15" away from any side wall or tall obstacle, such as a tall cabinet, and
3. b. The edge of the lavatory must be 4" from the wall or tall obstacle.
4. c. This means that the maximum width of the sink cannot exceed 22".
2. There are practical reasons for the 4" requirement. Any closer and it would be very difficult to clean the sink or the wall behind the sink.
3. In a small bath remodel, careful attention needs to be paid to the size of lavatory sinks to ensure that minimum offset distances are met. When in doubt, go smaller. Almost all fixture manufacturers make lavatory sinks designed to fit very small spaces.

1. This Guideline recognizes that the standard 32" or 36" vanity height is not appropriate for most people.
2. The former practice of installing 32" vanities as a compromise between the best height for children and the best height for adults has fallen by the wayside as builders recognized that after children are grown, adults are stuck with a too-low vanity height for many, many years.
3. The current better practice in remodeling a bathroom is to install a factory-standard 36" vanity, which is better but still too low or too high for most people.
4. If young children are using the vanity, rather than lowering the vanity, buy a stool.
5. However, the best practice in current bathroom remodels is to determine lavatory height based on the height of the user, and adapt the height of the lavatory to the user rather than requiring the user to adapt to the vanity height. For more information on ergonomic design see, "Body Friendly Design".

1. A shower may be of any shape, as long as:
   • A disk 30" (36" recommended) in diameter will fit within the walls of the shower and,
   • The shower head is inside the disk area. (This is something that does not appear in the building code but is in the plumbing code in most localities.)
2. Generally, to meet the code minimum size, a corner shower with an angled door (neo-angle door shower) cannot be any smaller than 32" x 32". A 30" disk will not fit inside the walls of a 30" x 30" neo angle shower. A minimum neo-angle shower size of 36" x 36" is recommended if space is available.
3. The smallest pre-fabricated shower available from most manufacturers is 32" x 32". This dimension is from stud to stud, so it may finish out to less than 32" x 32". A 30" disk will just fit inside the walls of this shower.
4. In a very small bath remodel, this minimum may still be too large. But, before you go any smaller, check with your local code officials. Sometimes, if a need for the shower can be demonstrated, they will allow a slightly smaller finished shower.
5. This Guideline must be coordinated with Guideline 3.

1. Pressure balanced,
2. Thermostatic mixing, or
3. Combination pressure balance/thermostatic mixing valve types. (IRC P2708.3)

1. These requirements are intended to reduce the risk of scalding. If the cold water fails for any reason, the shower is prevented from continuing to pump out hot water by these valves that either shut the water off or rebalance the temperature.
2. Some jurisdictions require these valves only on multi-family residences but regardless of your local code requirements, it is always a good idea to install one of these types of shower valves whenever a bathroom is remodeled. In our bathroom remodels, we always specify one of these types of shower valves. In our opinion, no conscientious bath remodeler will do anything else when remodeling a bathroom.
3. It is almost impossible to buy shower control valves from a mainline manufacturer that are not either pressure balanced or thermostatic mixing but some inexpensive valves from generic suppliers of imported shower controls may not have these features, so look for one or the other in any shower or tub valve. If a licensed plumber installs the valve, it will almost certainly be one of the other but it never hurts to ask.

4. What is the difference between the two types?
5. The older, pressure balanced valve invented by Symmons Industries in 1939 senses differences in water pressure between the incoming cold and hot water, and keeps the pressure balanced. But, it does not sense fluctuations in temperature, so that if the hot water turns colder, it does not know to reduce the flow of the cold water to compensate.
6. The newer thermostatic mixer technology senses variations in both pressure and temperature, and adjusts the water flow if either the water pressure or water temperature changes to keep the water within a few degrees of the set temperature. Electronically controlled mixers can even adjust the temperature of the water for each user.
7. Of the two, the Thermostatic mixer is preferred but it is also usually the more expensive.

1. In our bath remodels, we treat the code required 72" as the minimum height but build the enclosure to 3" or more above the shower rough-in as recommended by the guideline.
2. The shower rough-in is nothing more complicated than the height at which the shower arm comes out of the wall.

2. If a ceiling-mounted showerhead is used in a bath remodel, we generally build the enclosure to within 12" of the ceiling or to 84" in a bathroom with a standard 96" ceiling.
3. The shower enclosure should not extend all the way to the ceiling on all four sides unless power ventilation is provided inside the enclosure. Otherwise, steam from the shower has no place to vent. Eventually, the constant moisture inside the shower enclosure will result in mold and mildew forming on the shower walls. Leave a space at least 6-12" between the top of the shower enclosure and the ceiling on at least one side for ventilation.

So the final rule is: The shower enclosure should be a minimum of 72" from the finished floor of the shower or 3" above the shower rough-in, whichever is higher, but at least one side of the enclosure should not be closer to the ceiling than 3" to allow for ventilation.

1. Glass used in tub or shower enclosures (i.e. tub or shower door) or partitions must be tempered or an approved equal and must be permanently marked as such. (IRC R 308.1)
2. If the tub or shower surround has glass windows or walls, the glazing must be tempered glass or approved equal when the bottom edge of glazing is less than 60" above any standing or walking surface. (IRC R 308.4.5)
3. Any glazing (i.e. windows or doors) whose bottom edge is less than 18" above the floor must be tempered glass or approved equivalent. (IRC R 308.4.7.2)

1. This is a safety measure. Most building and safety codes require glass installed closer than 18" to the floor to be tempered because it is easy to break the glass by inadvertently kicking it. This applies to any room in the house, not just the bathroom. In planning a bathroom remodeling project where windows are involved, it is often easy to forget that glass over a tub or in a shower must be tempered.
2. The 60" inch rule is also a safety measure to prevent you from putting your elbow through window glass while showering or bathing. Any glass at or above 60" is considered high enough that it is unlikely to be accidentally broken but any glass lower than 60" is at risk.
3. Many older homes include bathroom windows that do not comply with these rules. Whether you have to plan for replacing non-conforming glass when remodeling a bathroom generally depends on the requirements of local code authorities.
4. Where tempered glass is required, glass block may ordinarily be used instead but check with your local building code authority to make sure.

1. This guideline refers to permanently installed steps, not temporary, removable steps.
2. Steps in a bathroom where water can make them slippery are generally not a good idea. There are too many better ways to deal with getting into and out of a bathtub, including the many walk-in bathtub designs on the market.
3. Certain bathroom styles, however, include bath steps as a design feature. For example, a Japanese Bath that includes a soaking or ofuru tub generally includes steps to get in and out of the tub.
4. As a general rule, however, if at all possible, plan your bathroom remodeling project without bathtub steps of any kind.

1. All equipment, including access panels, must be installed as per manufacturers' specifications. (IRC M 1307.1)
2. All manufacturers' instructions must be available for installers and inspectors and left for homeowners. (IRC P 2720.1)

1. All bathroom equipment and accessories installed during a bathroom remodel must be installed following the manufacturer's instructions. Most equipment made for use around water is tested and certified by various testing organizations to be safe only if installed in the way the manufacturer intends. If the manufacturer requires an access panel for equipment installed in a bathroom, the access panel must be built and must be the size and location specified in the manufacturer's installation instructions. This applies primarily to whirlpool tubs.
2. Most local codes require that installation instructions for bath equipment and fixtures be delivered to the homeowner and available to the building or plumbing inspector.

1. The Guideline implies that a toilet compartment must have a door. Actually, more toilet compartments are built without doors than with.
2. An inswing door can be used if the width of the door is added to the depth of the compartment. For example, if the compartment has a 24" door, add 24" to the 66" length of the compartment. The new 90" depth accommodates the inswing of the door.
3. This guideline also applies to a bidet compartment.
4. If both a bidet and toilet or toilet and wall urinal are built into one compartment, the arrangement of fixtures within the compartment must conform to Guideline 20. This usually results in a minimum compartment width of between 62" and 65", depending on the width of the fixtures selected.
5. If the compartment needs to be wheelchair accessible, the minimum width is 60".

1. Place a mirror above or near the lavatory at a height that takes the user's eye height into consideration.
2. The toilet paper holder should be located 8" to 12" in front of the edge of the toilet bowl, centered at 26" above the floor.
3. Additional accessories, such as towel holders, soap dishes, etc., should be conveniently located near all bath fixtures.

1. Mirrors: There can be no hard and fast rules for setting a mirror. Mirrors come in various sizes and shapes, and so do users of the bathroom. The general rule we follow is to set the mirror so that the top of the glass portion is a few inches above the eye level of the tallest user. The mirror itself should be tall enough to permit all users to see from the top of his or her head to the top of the sink.
2. Towel Bars and Rings: Towel bars should be set at a convenient height that looks good to you. For most bathrooms, 48" - 54" from the finished floor is usually about right. If the bath has a tile wainscot, you may want to adjust this height to avoid drilling through the tile. For children, a lower bar is often more convenient and encourages hanging up the towel. However, always leave enough space below the towel bar for a towel to hang freely without touching the floor or a surface below the bar. Generally, the absolute minimum height is 36" for towels, 18" for washcloths.
3. Robe Hooks: Robe hooks should be set at 66" or higher, depending on the height of the user. Tall users might find that a higher hook is needed to keep the robe from touching the floor.

1. At least one wall-switch-controlled light must be provided. A switch must be placed at the entrance. (IRC E 3901.6, IRC E 3803.2)
2. All light fixtures installed within tub and shower spaces should be marked "suitable for damp/wet locations". (IRC E 3903.8)
3. Hanging fixtures cannot be located within a zone of 3' feet horizontally and 8' vertically from the top of the bathtub rim. (IRC E 3903.10)

1. At least one electric light, controlled by a wall switch, must be provided in a bathroom. A pull-chain is no longer allowed. Other sections of the electrical code require that the switch be located near the entry door.
2. The safest light over a tub or in a shower is a recessed light with a waterproof lens. If a surface-mounted ceiling lamp or hanging (pendant) lamp is used, then it must be 96" above the rim of the rub or 36" outside the edge of the tub. This rule seeks to prevent people from grabbing a handy light cord to steady themselves if they lose their balance in a tub or shower, and possibly pulling the live light fixture into the water. The light must also be high enough or outside the tub far enough so that a bather could not accidentally reach out and touch the light fixture while standing in water.
3. Ceiling lights are usually wanted over the tub but since the ceiling in most baths is 96" from the floor, the light cannot possibly be installed 96" from the top of the bathtub rim, which is usually between 13" and 16" from the floor. The idea behind the rule is to keep people from grabbing onto electrical fixtures for balance if they start to slip. Falling is bad enough but electrocution combined with falling is even worse. Recessed lighting above the tub, if the light is enclosed with a water-resistant lens, is fine and will be approved by nearly all local inspectors.

1. Generally, a bathroom should be 10° warmer than the rest of the house when someone is bathing or showering. Normal warm room air on wet skin feels cold.
2. Whatever the supplemental heating solution, it should not involve blowing air. Moving air on wet skin feels cold no matter how warm it is.
3. Underfloor electric radiant heating, heat lamps, and wall-mounted radiant heating should be considered. An inexpensive panel heater like the one shown or a baseboard heating unit are inexpensive additions.
4. Supplemental heating should include a separate room thermostat and some form of automatic shutoff or timer to ensure the supplemental heat is not left on once the need for it has passed. Otherwise, a lot of electricity is wasted.