Chapter 4: Circulation

These universal design features apply to hallways & pathways throughout the home and movement throughout indoor & outdoor living areas.

Residential Universal Design Building Code, 2024 version. © The UD Project.

Section 4.1: Measurements

4.1.1 Pathway widths ≥ 42 inches.

Hallways and pathways should be no less than 42" (107cm) wide at the narrow-most points.

42" (107cm) of minimum width at the narrow-most point is ideal for anyone who uses a mobility device, parents who push strollers, or offers easy access for moving large items. Even if the full width isn’t used in its entirety, an element of safety results from adequate room to move side-to-side.

When considering furniture placement, ensure no less than 32" (81cm) of width between all travel points.

4.1.2 Interior door widths ≥ 32 inches.

Interior doors should be no less than 32" (81cm) wide.

Where possible, 36" (91cm) interior doors are ideal.

This applies to the width of the door itself. Doorways will often have less clearance when considering door jams and the door thickness, if on a hinge, when open. Swing-away hinges can add extra clearance if needed.

Please refer to 3.1.1 for exterior door widths.

4.1.3 Interior thresholds = 0.0 inches.

Interior thresholds should be flush, i.e., no change in height from the floor.

This includes transitions between rooms that may not be clearly defined as thresholds.

If you can’t easily roll a small ball (e.g., a tennis ball) over the threshold, then the threshold can create difficulty for some people. Like the ball might stop with a threshold in the way, so will smaller wheels on the front of walkers and wheelchairs. If this happens to someone using a wheelchair, their chair may stop, but momentum will keep their body moving forward, leading to potentially falling onto the ground. This also applies to people who might have difficulty picking up their feet or have their arms full and cannot see where to do so.

Please refer to 3.1.2 for exterior door thresholds.

Section 4.2: Features

4.2.1 No interior steps.

No steps should be required to access any inside spaces. This applies to every area inside the home, including storage.

Multiple floors? See Sections 4.3 and 4.4.

Access needs to be everywhere. Sunken rooms, elevated platforms, or any rooms with one or more steps are a no-go for universal design. Avoid areas with multiple levels unless there is a no-step option available. Living spaces at different floor levels (i.e., down a step, up a step) can help define different areas, but they're confining to those who have trouble negotiating steps.

Steps prevent efficient movement throughout the home as any person must alter their movement pattern and divide attention to locate the steps for navigation.

4.2.2 Easily manipulated door hardware.

Door hardware should be operable with one hand while not requiring pinching or grasping.

Use door hardware that requires minimal physical effort, such as lever handles, pulls, electronic locks, and power door openers. Knobs and handle sets are difficult to use if hand function is impaired. Avoid anything that requires pinching or grasping for use.

The physical actions necessary to open a door can make it difficult to maintain balance and cause frustration or fatigue. The rule of thumb is that it should only require someone about 5 pounds of pressure to open a door.

4.2.3 Unobstructive door swings.

Open doors should not obstruct paths of travel wherever possible.

Pocket doors and barn doors are great options for universal design. This applies to doorways between spaces and entrances to closets and pantries.

If space is limited, there are options to maximize clearance for interior doors that aren't realistic for most exterior doors. This allows for easier movement through the home, especially when moving furniture from room to room, carrying laundry baskets, or walking with children in tow.

4.2.4 Visual contrast for transitions.

Visual contrast should exist for transitions between spaces. Visual contrast can be achieved with color or pattern.

The color defining a space (e.g., flooring, door frames, etc.) must have a minimum contrast ratio of 3:1 against adjacent space(s).

Contrast is a feature that assists anyone who has trouble with vision in identifying the separation between spaces. It also decreases visual fatigue in navigating a space so people can divert their attention to other tasks like talking on the phone or carrying items.

The same 3.1 ratio is used in accessible web design. Check color contrast at WebAIM.

Avoid busy patterns (especially in wallpaper) to reduce visual noise.

4.2.5 Solid & high-contrast wall colors.

Walls should contrast with skin tones for enhanced visual communication.

Color walls (especially blue tones) are ideal for creating contrast against skin tones, which is helpful for people who rely on visual communication methods like sign language. Neutral colors are fine but should be used carefully. Keep sight lines in mind when planning interior colors.

4.2.6 Rest areas.

Consider including spaces for benches or seats (e.g., alcoves) in hallways or along longer travel paths between spaces. These spaces can also be used for additional furniture for storage if rest areas aren't needed.

Some individuals have poor endurance and can fatigue quickly when traveling longer distances between spaces. A place to rest can make navigating the home easier and will encourage increased physical activity.

4.2.7 Slip-resistant, trip-resistant, and durable flooring.

Floor and pathway surface types should be selected to minimize the potential for slips, trips, and/or falls. This includes long-term durability. Flooring and surface selection should be intentional and appropriate for all intended uses in spaces inside and outside of a home.

It’s important to choose flooring that will hold up to everyday use and will not break down or fall apart easily. Individuals using mobility devices can inadvertently wear down flooring more quickly than typical, so plan accordingly. Also, look for flooring that is easy to clean to make life easier for everyone.

Many variables contribute to slip resistance, such as flooring type, exposure to natural elements or other contaminants, or footwear someone is (or isn't) using. It's important to accommodate as many scenarios as possible.

Rugs:

Loose rugs are a potential hazard for anyone, especially if they have trouble seeing or have decreased balance. This includes throw rugs. Don’t use them unless they are (1) recessed into a floor with no elevation change between the floor and (2) without any gaps in the installation between the floor and the rug.

Carpet:

Wall-to-wall carpet is acceptable if the pile is ≤ 0.5" (1.25cm) and the carpet is either (1) permanently installed or (2) secured with backing or padding to minimize bunching or other movements.

4.2.8 Low-glare flooring.

Flooring should be minimally reflective, particularly in areas with direct natural light.

Natural light is important but can create glare that makes it difficult to confidently and safely navigate some spaces in a home. Reflective flooring can cause people to cover windows unnecessarily to block natural light, which can be detrimental to mental health.

4.2.9 Evenly-lit.

The lighting design should include a combination of natural & artificial light sources that minimize shadows and glare, day and night.

Lighting should minimize shadows and be designed to be as glare-free as possible. This is useful for everyone but especially important for people who rely on visual communication. Lighting low to or just above the floor can create cues about the direction to follow. Use low lights to help define the pathway, but don't make these lights a focal point.

Recommended: indirect and low lighting:

Using indirect ambient lighting and low lighting that illuminates the floor without visible bare bulbs or translucent covers (from a seated or standing position) is ideal. Indirect lighting reduces eye strain and is more calming than direct lighting.

The option to adjust the intensity of ambient lighting (e.g., with a dimmer) should be used wherever possible.

Section 4.3: Elevator

While one-story living is ideal for universal design, elevators that provide access to every floor are the only solution for vertical circulation in multi-story homes.

Anyone should be able to access every part of the home independently.

There's a popular opinion that it's adequate to stack closets or add other features in floor plans that can support the future installation of an elevator. While the intention is good, accessibility will be limited, which is not what universal design is about.

Also, there should be a minimal dependency on an elevator if redundancy is unrealistic (e.g., small single-family homes vs. large multi-family buildings). The ability to safely and quickly exit a home in a fire needs to be prioritized.

4.3.1 Elevator service to all floors.

An elevator must provide access to any floor that is accessible by stairs.

If a home has multiple stories, an elevator providing access to every floor is necessary for true universal accessibility. It's the only option to accommodate every homeowner, guest, or tenant.

4.3.2 Interior width ≥ 36 inches.

The interior width of an elevator car should be no less than 36" (91cm).

4.3.3 Interior depth ≥ 48 inches.

The interior depth of an elevator car should be no less than 48" (122cm).

Elevators must be large enough to accommodate mobility devices. If possible, choose an elevator large enough to also accommodate a companion.

4.3.4 Level entrance.

The entrances to an elevator car should be level with the floor outside of the door. The threshold should be no more than 0.0" to comply with 4.1.3.

Some elevators require a small step or a small ramp to get in and out. These should be avoided unless recessed into the floor to create a level transition.

4.3.5 Automatic -or- push-to-open door.

The elevator door(s) must open automatically or be able to be pushed open with less than 5 pounds of force from the inside without the need to manually unlatch door hardware. If doors need to be locked to prevent access from the outside when the car is on a different floor, they should unlock and unlatch automatically.

Small elevator cars that do not allow someone to turn around inside must be easy to exit. This is particularly important for people who use mobility devices.

Exception

This requirement may be waived if the interior floor space of the car is at least 5x5' (60x60" or 152x152cm). The door hardware must comply with 4.2.2.

4.3.6 High contrast controls.

Elevator controls should be highly visible against the interior wall of the elevator car.

Contrast is a feature that assists anyone who has trouble with vision. Elevator controls should be easy to see. Backlit controls are even better.

4.3.7 Interior lighting.

Lighting should be used inside the elevator.

There's no good reason for someone to ride an elevator in the dark and struggle to locate the controls or door hardware. Automatic lighting triggered by the door opening or a motion detector is ideal.

4.3.8 Battery backup -or- powerless operation.

The elevator should be able to return to a ground-level floor in case of a power outage.

Also applicable: 10.2.15 Breaker panel connection for backup or redundant power.

If the power goes out, it's important for someone unable to safely navigate stairs to access an exit.

Section 4.4: Stairs

Definition: This section defines "stairs" as any place where multiple steps are used together.

4.4.1 Tread width ≥ 36 inches.

The width of the area where someone places their feet on a step should be no less than 36" (91cm) wide.

4.4.2 Tread depth ≥ 11 inches.

The depth of the area where someone places their feet on a step should be no less than 11" (28cm) deep.

4.4.3 Stair height between 5.5-7 inches.

The height between the top surface of stair treads should be no less than 5.5" (14cm) and no more than 7" (18cm).

Stairs must be as safe as possible for universal design, necessitating uniform dimensions for each step. Unlike small steps on a ladder, each stair should be deep enough to allow people to put most of their foot on the step when going up/down the stairs.

36" (91cm) of minimum width at the narrow-most point is ideal for anyone who uses a mobility device or offers easy access for moving large items. Even if the full width isn’t used in its entirety, there’s an element of safety that results from space to move side-to-side.

4.4.4 Enclosed risers.

Risers (the backs of steps) need to be enclosed.

Risers should not be open to prevent someone from stepping too far forward and catching a toe under the next step, which creates a fall risk. This also increases safety for small children.

4.4.5 Slip-resistant tread surface.

Tread surfaces should be slip-resistant and not allow footwear to slide easily.

Slip-resistant flooring choices on stairs in stairwells are important to reduce the occurrence of a trip or fall. It's important to choose flooring that will hold up to everyday use and will not break down or fall apart easily. Also, keep it easy to clean and make life easier for everyone.

4.4.6 Visual contrast between the frontmost 2 inches of tread and the remaining rear tread.

Contrasting colors (light/dark) need to be used between the first 2" (5cm) of the front of the tread and the rear of the tread surface.

Visual contrast is a feature that assists anyone who has trouble with vision in identifying the separation between steps. It is also generally helpful for anyone navigating the stairs at night or early in the morning when it can be more difficult to see. The contrast on the tread surface is for when people are descending stairs.

4.4.7 Visual contrast between the front of the nosing or the radius of the tread edge and the risers.

Contrasting colors (light/dark) must be used between the nosing and the risers.

Visual contrast is a feature that assists anyone who has trouble with vision to identify separation between steps, or for anyone who has trouble seeing the stairs during darker hours. The contrast between the nosing or the radius of the tread edge and the risers is for when people are ascending stairs.

4.4.8 Handrails on both sides.

Handrails need to be installed on both sides of the stairs.

Handrails on both sides of the stairs are a universal design feature that gives people options for stabilizing themselves when going up or down the stairs.

4.4.9 Handrails extended beyond steps and continuous for changes in direction.

Handrails need to be extended beyond the top and bottom steps and continuous throughout the entire stairwell if there are any landings or changes in direction.

Extending the handrail one foot beyond the top and bottom step increases safety by helping people maintain balance. They also serve as a tactile alert for people with vision impairments to indicate a transition is about to occur. If the stairs change direction, curve the handrail around the walls for uninterrupted support.

4.4.10 Landings ≥ 48x48 inches at top and bottom.

A landing area with a minimum size of 48x48" (122x122cm) needs to exist at both the top and the bottom of the stairs.

A wide-open landing at the top and bottom of any stairwell is important for universal design because it provides adequate space to maneuver on and off the steps and space for two-way passage. If mobility equipment is used, this space gives individuals and/or other family members room to move around without barriers.

4.4.11 Evenly-lit with stair lighting.

Both overhead lighting and stair lighting (low & close to steps) should be used to maximize safety.

Thoughtful and thorough lighting is necessary for safe and easy navigation of stairs. The objective should be to minimize shadows. The placement of light sources is important for people to maintain focus on where they are going while avoiding glare.