Universal design should be the standard rather than the exception. It should be expected that any well designed building would provide the minimal amenities of a usable approach, a supportive site, landscaping that can be enjoyed by people of all abilities, and accessible routes throughout the building. Universal design meets the needs of all users, not just the average or the exceptional.

Universal design is a reinforced elevator shaft inside stacked closets so that a residential elevator can be added at a later date. It is not a temporary ramp ruining the appearance of the building, attached as an afterthought, and usable by only a few. Universal design is an elevator used by all, not an open lift separating the users from those who are able to negotiate the adjacent stairs. Universal design integrates, it doesn't segregate into user groups.

Emblems of age and disability are often specified by well meaning designers attempting to make a building accessible. Universal design is invisible; it does not advertise the physical differences of the user.

Exterior Planning
Universal design begins with a covered entry at each exterior doorway. This will be appreciated by anyone who is looking for keys or waiting for a ride. Outdoor seating in this area is also helpful. Plan the entry with a slip resistant surface that drains away from the door. The entry should be protected from wind to allow the door to be easily opened.

If a passenger loading zone is necessary, it should be visible from the front door. It must be slightly sloped for drainage, not to exceed 1:50. At a minimum, it must be 5 ft in width and 20 ft in length parallel to the vehicle space. In a passenger loading zone or garage, a minimum vertical clearance of 9 ft 6 in is needed by some vans.1 Well lighted access aisles should be provided in all parking areas or garages for transfer to a car or van. People who transfer to a car equipped with hand controls require a 5 ft clear space to completely open the driver side car door and transfer. Those using a perpendicular side lift on a van will require a wide access aisle (8 ft) on the passenger side of the 8 ft parking space.2 The access aisle should be marked with diagonal striping. The space and access aisle must be level (not exceeding a slope of 1:50 in all directions).3

A universal parking space is 11-ft wide with a 5-ft wide access aisle. It provides space to transfer from either a car or a van. This extra width also allows users to park on one side or the other depending on transfer needs. This is especially important in "front in" only parking (where users cannot back in to facilitate transfer). When universal spaces are provided, van accessible spaces are not required. Special "van-accessible" signage is not required in universal spaces, but each space must be marked with the international symbol of accessibility.

Two accessible parking spaces may share a common access aisle, but diagonal spaces must have access aisles on both sides since vehicles cannot back in. Provide all accessible parking spaces in the lot closest to the accessible entrance, but calculate a minimum of one accessible parking space per lot.

From the access aisle or passenger loading zone, an accessible route should be provided to all buildings on the site. The route should be free of auto traffic and protected from adverse weather elements. It should be well illuminated and maintained. The minimum clear width for a single wheelchair is 3 ft, but a universal route is 44 inches in width (except at tight turns) to accommodate the needs of both adults and children who need increased maneuvering space. When the route crosses a driveway, it must remain level or the slope can pull people in wheelchairs out into the street.

Provide seating and resting places on longer routes. Street furniture and equipment should be recessed into alcoves, and a companion seat must be provided next to each space planned for a person in a wheelchair. Water fountains, benches, waste receptacles, telephones, trees, and other objects which overhang the route are obstacles to everyone and should be contrasted from their surroundings. For blind adults, these objects must protrude no more than 4 in between 27 in above the finished floor (a.f.f.) and 80 in a.f.f. Blind children may need protection from protruding objects as low as 1 ft a.f.f.

Maps of the parking area are always helpful, especially to people with differences in hearing or speech who may be hesitant to ask for directions. Install adequate lighting for map use and crime prevention. Maps with raised letters or Braille symbols are important, as are auditory cues such "talking signs" which deliver verbal information by remote control.

A quiet building site is necessary for people with differences in hearing, as well as for people who rely more on their sense of hearing than on their vision. People with speech differences also need quiet spaces in which they can be easily heard, and people with mental, learning, and developmental differences profit from reduced noise levels. Select a site away from major roads, airports, and railroads. Windows and doors should be oriented away from any sources of noise adjacent to the site. In existing construction, earth berms and exterior plants can be placed in front of windows and doors to buffer noise. An earth berm can also be used as a ramp.

Elevated gardens are convenient for gardeners who get stiff while kneeling, for people using mobility aids, and those who have trouble reaching the ground. Pots and planters should be at least 2 ft in height and should be accessible from both sides if they exceed a 2 ft depth. They can be mounted on stands, walls, or racks. Specify nontoxic plants to protect children, pets, and people with allergies.

Flowerpots and baskets can be suspended by a pulley system that allows them to be lowered for pruning and watering. Choose watering products which do not become too hot to hold after sitting in the sun. An alternative method for watering is a drip irrigation system. In addition, carts and watering wands can be used with gardening activities. A vertical garden offers easy access to plants. One version, featured by the Chicago Botanical Gardens, consists of a coarse screen mounted loosely to a wall. The screen is lined with sphagnum, filled with potting soil, and planted through holes cut in the screen.

Patios offer sheltered gardening. They also provide an area in which to move the bed outdoors. An accessible cooking grill should be provided, and seating should be at wheelchair seat height (17 in to 19 in for adults and 11 in to 17 in for children depending on age). Transfer walls at a lower height may be added to move from a wheelchair to the grass or sand. Patios and recreation areas should be covered and extend into an accessible escape route.

Attach the garage on the same level as the main building. Include a covered two car garage to protect the user, as well as an attendant or guest. In commercial spaces, plan a covered connection between buildings. A covered exterior route may be critical for emergency escape. Such a route usually consists of a covered sidewalk around the perimeter of the building. For security and safety, the sidewalk should be well-lighted. It must be adequately drained, yet free of gratings with wide openings which could catch on wheels and crutches. Openings in gratings must be of a size that does not permit passage of a ½ diameter sphere, and elongated openings must be perpendicular to the route of travel.

Brick, sand, and cobblestoned surfaces, and loose soil are examples of textures that are unstable and difficult for many people. Soil stabilizers such as pine resin emulsion, flyash, bentonite, ground seed hulls, latex polymers, and enzymers should be selected according to soil type.5 A stabilizing mat can also be used over loose soil or sand.

Abrupt edges and drops in the sidewalk pose a tripping hazard and a barrier for people using mobility aids. Specify adequate drainage and sidewalk sub-base construction to prevent settling and the resulting changes in level. Ramp existing changes of level exceeding ½ in. Bevel changes of level between ½ in and ½ in.6

Where an accessible route crosses a curb, provide a curb ramp with the least possible slope. A maximum slope of 1:12 is permitted in new construction. Curb ramps must not extend into the parking access aisle or the accessible route. When the accessible route crosses an island, provide a level space of at least 4 ft between the curb ramps. It is usually best to eliminate the curb ramps entirely by cutting the island down to ground level.

Specify flared sides on curb ramps (preferably with a maximum slope of 1:12) since steep sides can pose a tripping hazard to pedestrians. When using flared sides on a diagonal curb ramp at a marked crossing, at least 24 in of straight curb is required within the crossing area. A minimum 48 in landing at the bottom of the ramp must also be contained within the marked crossing to allow people with vision differences to stay oriented.

Curb ramps may be a hazard to people with differences in vision who use curb edges to signal the beginning of the street. Use a uniform textural cue to prevent this problem. Also use color and texture on sidewalk intersections that lead directly into the street or parking lot and around the perimeter of reflecting pools.

Ramps
Ramps are poor design. Older people often experience instability on ramps and prefer stairs. People using mobility aids are frequently segregated to the ramp while everyone else takes a separate path. Ten percent of people with ambulatory differences and over 20 % of wheelchair users cannot use a 1:12 ramp. Over two-thirds of wheelchair users cannot use a 1:12 ramp in a 30 ft length.7 If possible, eliminate ramps through earthwork and site grating. If the approaches to the building do not exceed a slope of 1:20, ramps will not be necessary. If ramps are the only choice for access, try to keep the maximum slopes at 1:20. This slope is also recommended for children.

Permanent ramps attached to a home may reduce the resale value and limit prospective buyers. Wood or metal ramps are easy to dismantle. Wood ramps are also easier to build and can be modified if mistakes are made in construction. Use fire retardant wood that has been pressure treated (or is decay resistant, like redwood). Hot dip galvanized bolts and screws (with washers) should be used to resist corrosion.

Plan fire retardant residential wood ramps with commercial nonskid surface finishes. Do not specify carpet for ramps, especially indoor/outdoor carpeting which may become slippery when wet. Sheet vinyl and painted surfaces are also slippery when wet or dusty, but ribbed rubber matting works well. Install the ribs to run across the width of the ramp.

Permanent concrete ramps are usually more expensive than wood, but concrete ramps are easier to maintain and last longer. Specify a sand float or broom finish brushed across the slope, not with it, to prevent slipping. A broom finish across the ramp is also easier for blind people to sweep with a cane. Avoid exterior ramps in climates with ice and snow, or cover them with a canopy. Built in electric heating coils can also be considered.

Portable ramps are the least expensive method, but they can be too steep for many people to use. If the ramp is 3 ft in length and used on a 6 in step, the user must negotiate a 1:6 slope. This is twice as steep as ramps built to most required standards; even a 1:10 slope is too steep for most wheelchair users and could cause the wheelchair to tip.8

To meet minimum standards, the slope of an interior or exterior ramp must not exceed 1 in of rise for every 1 ft of length (1:12), and the cross slope must be no greater than 1:50. When a 1:12 ramp is not the "least possible slope", it is not complying with ADA. If possible, use a shorter ramp with a more gradual slope. The ramp must never exceed 30 ft in length without a landing. A 20 ft length is a more universal solution, especially for children.

Curbs with a minimum height of 2 in must be installed on both sides of the ramp to serve as guardrails for wheels and crutch tips. Use low curbs instead of sidewalls to prevent scrapes and bumps.

Handrails must extend 12 in beyond the top bottom of the ramp, and the extension must be parallel to the floor. Handrails can be used by both pedestrians and people in wheelchairs who pull themselves up the ramp. Handrails must always be installed on both sides of a ramp if the ramp has a rise greater than 6 in (or a length greater than 6 ft). Install at a height of 34 in to 38 in for adults and another set at 20 in to 28 in for children, depending on age. Handrails are not required by ADA on curb ramps or ramps adjacent to assembly seating areas. Shorter ramps without handrails must have flared sides to prevent tripping accidents.

The landings at the beginning and end of the ramp and at any turn around point must be 5 ft in length and as wide as the ramp. The landings must be slightly sloped (not exceed 1:50) for drainage.

When the door opens onto the ramp, the entrance platform must extend at least 18 in to 24 in on the side next to the latch so that the door can be opened without backing up a wheelchair or walker. The ramp should be directed toward the latch side of the door if the door opens onto the ramp. If the door opens into the building, orient the ramp to the hinge side of the door.

The width must be a minimum of 3 ft for one way traffic including wheelchairs and walkers, 4 ft for two way ambulatory traffic, and 5 ft for two wheelchairs to pass. Since the width of a ramp is an almost insignificant factor in the total cost of the ramp, a five ft minimum width is desirable whenever possible.

A ramp into a swimming pool should not exceed a slope of 1 ft of rise per 10 ft of length.9 It must be 3 ft wide with edging and handrails on each side, which can be used to guide a shower wheelchair during entry and exit. Shower wheelchair users become buoyant (and lose control of their wheelchairs) at a depth of 2 ft 10 in 10 (2 ft 6 in for children).11 A portable lifting device can be used in place of a ramp where space or budget is limited.

A series of steps can also be used to access a pool, with the highest step planned at wheelchair seat height (between 17 in and 19 in for adults and between 11 in and 17 in for children).12 In one creative installation, steps were replaced with a series of smooth rocks that is incorporated into the design.

An accessible 4 ft route should be planned around the pool. Both the ramp and the route must have a nonslip surface.

Lifts, Elevators, Stairs, and Areas of Rescue Assistance
Lifts and Elevators. Universal design of lifts and elevators involves more than code compliance. Ambient light levels should be increased in the interiors by the use of lighter finishes and diffuse light sources. Mirrors and confusing patterns may reduce stability in a space which is inherently unstable. Redundant cues (such as audible and visible floor notification) are particularly important to decrease reaction time and increase efficacy including contrast around the edges of the floor covering.

In residential environments and unusual commercial circumstances13, a wheelchair lift may be used in place of an elevator. On a lift with a door, specify a locking device that prevents the lift from moving unless the door is locked. The lift should be designed to protect against entrapment under the platform and any failure that could cause the platform to drop. A slippery or jolting platform may cause the user to lose his or her balance. For visual integration, the lift can store in the floor or ground when not in use.

Two types of inclined lifts are available to lift a seated user up a stairway. Both usually following the handrail. The first type works well for an ambulatory use, but the a wheelchair user must transfer onto a seat and then into a second wheelchair at the other end. This type is used when the lift serves one particular individual or where the stair width is limited. The lift seat stores at the bottom of the stairs to permit unobstructed use of the stairway. Folding seats are also available. The second type of inclined lift includes a fold-down platform which caries the user in their wheelchair. If a lift requires a separate power unit, be sure it does not block the accessible route.

If any of the various types of lifts are chosen over an elevator, the designer should pay special attention to the controls. Keyed lifts should not be used in public areas unless some foolproof method is developed to prevent the keys from being lost. Use keyless lifts in easily supervised areas where children can be prevented from playing on them. A "constant pressure" switch stops the lift immediately when released, but it is more difficult to operate than a simple on/off switch.

Freight elevators are not acceptable as the only vertical access for people who use wheelchairs, and most standards prohibit their use to meet accessibility requirements. For an accessible elevator, a minimum interior size of 4 ft 6 in by 5 ft 8 in should be maintained but an existing cab that is at least 4 ft by 4 ft clear may be acceptable in some situations. The door should be a minimum of 3 ft wide.

The elevator must be automatic and self leveling (within a tolerance of 1/2 in). Leveling should be tested with a full load as well as without a load.14 The clearance between the car sill and the hoist way must not exceed 1 ¼ in. The elevator should start and stop smoothly, and a fold down seat (for more than four stops)15 and a stationary handrail should be provided to improve balance.

A visual indicator on each elevator control button should light when touched and extinguish when the command is completed. All car controls, as well as the car platform, landing sill, and car threshold, should be illuminated to at least 5 ft candles.16 Position indicators must incorporate redundant cuing, offering both visual and audible cues. In the hall, an audible signal must sound once for the up direction and twice for the down (or use a verbal announcement of up or down).

Call buttons must be installed at a height of 3 ft 6 in a.f.f., with the up button on top. Consider a second call button for adults of shorter stature or children installed at a height of 3 ft a.f.f.17 Any object placed or installed beneath the call buttons must not project into the space more than 4 in.18 A call button must be a minimum of ¾ in in diameter. Hall lanterns, indicating which car is answering the call, must be a minimum of 2 ½ in in the smallest dimension and must be centered over the door at 72 in a.f.f. In addition, a 2 in high raised floor designation with Braille must be mounted on both jambs at 5 ft a.f.f. A second designation could be installed at 48 in for children when appropriate.19 A tactile star must be provided on both jambs at the main entry level.

Interior control panels must be installed within reach for adults of shorter stature, children, and people in wheelchairs. Controls for children should be installed no higher than 3 ft a.f.f.20 Some panels are designed to be mounted horizontally to improve reach. Arrange the numbers in ascending order, reading from left to right. A floor number or other raised designation must be installed to the left of the button and must contrast with the background. Numerals above the door must illuminate, and a signal must sound as the car passes or stops at a floor. A verbal announcement at each floor is preferred by people who are blind, and this may be substituted for the signal.

Many people with mobility and vision differences take a little more time to find the elevator and enter the car. The elevator must have an audible and visual signal to indicate arrival, and this signal must be adjusted to allow extra reaction time. ADA and UFAS only require a minimum of 5 seconds from notification until the door begins to close. The following formula is used to calculate the time (T) a door must remain open from notification: T=D/(1.5 ft/s) where D equals the distance from the call button to the center of the elevator door. But earlier notification inconveniences no one since it does not increase the amount of time the door is actually open. According to ADA, the door can be open for as little as three seconds. If the door becomes obstructed, it must reopen without requiring contact and remain open for at least 20 seconds.21 The reopening device must be activated without physical contact by sensing any obstructions between 5 in a.f.f. and at least 29 in a.f.f.

In addition, if an emergency two-way communication system is provided inside the car, it must comply with the accessibility requirements for height, hardware, and length of cord, if any. It must not require the user to speak or hear. A separate verbal system (like a telephone or an intercom) may be incorporated in addition to an alarm system. Push button intercoms are easier to use and tougher to vandalize than systems requiring the use of a handset. Only the nonverbal alarm system is required, however. Instructions for use should be both tactile and visual.

Areas of Refuge.  During an emergency evacuation, elevators in most buildings cannot be used as a required exit. Many people cannot use stairs for the evacuation, so the ADA Standards requires construction of a safe place22 to wait for assistance. The building should also be equipped with evacuation equipment.

These "areas of rescue assistance" or "areas of refuge" are required in the same number as required exits. They must be provided in all new buildings on accessible floors which solely depend on elevators (unless the building has a supervised automatic sprinkling system). The areas are usually placed adjacent to (or inside) stairways or in a pressurized elevator lobby, and each area must have clear floor space for two wheelchairs (unless reduced in size by a local authority). There are also requirements for instructional signage and two-way communication (both visible and audible) to request help and receive confirmation that help is on the way.

Stairs and Handrails.  Many people have difficulty negotiating spiral or curved staircases, which require balance and dependence on the handrails. Straight staircases should provide a safe stopping place midway between floor levels to help those who are prone to dizziness or those who need to conserve energy. A seat on the landing is also helpful to many.

At least 3 ft of clearance must be provided between the handrails on stairs (4 ft on stairs adjacent to an area of refuge). They must be installed on both sides of the stair to accommodate people who are stronger on one side than the other. They must be continuous on the inner rail at switchbacks and doglegs, and the gripping surface must be uninterrupted. Mount the top of handrails at a height of 2 ft 10 in to 3 ft 2 in above the stair nosing.23 A lower handrail can be installed at a height of 20 in to 28 in in for use by children (depending on age). It should have a diameter of 1 in to 1 ¼ in for maximum safety.24

Each handrail should have an outside diameter of 1 ¼ in for the strongest and most comfortable grip for both children and most adults. It must have rounded ends or return to the wall, floor, or post to minimize the chance that it will snag clothing and cause a fall. The handrail must not extend into the pedestrian pathway by more than 4 in.25 A handrail must also clear the adjacent wall by exactly 1 ½ in. This is enough space to allow a panic grab during a fall, but not wide enough to be dangerous. Some people place their entire lower arm on the handrail to push up, and the arm could become wedged between the wall and the rail if a larger clearance is allowed. To prevent scraped knuckles, the wall surface behind the handrail must not be rough-textured. Texture can be used on the handrail itself for improved grip and orientation. Notches or grooves can be cut in the rail to identify location. Braille and audible cues may also be added. Handrails must not rotate within their fittings.

A handrail can be recessed to a maximum of 3 in if the recess extends at least 18 in above the top of the rail.26 It must extend 12 in beyond the top and 12 in plus the width of one riser beyond the bottom of stairs, and the extension must be parallel to the floor. At the bottom, the handrail must continue to slope for a distance of the width of one tread. The remaining 12 in must be horizontal.

People who are a little unstable may be able to manage steps more easily than ramps, but do not design steps with abrupt or square nosings which project more than 1 ½ in. It's easy to catch a toe on this overlap. Use wedge shaped fillers on existing square nosings. Open risers are nearly impossible for use by people with canes or other mobility aids. Consider a clear filler for an open riser Keep every riser constant at the same height (7 in maximum preferred) and every tread constant at a minimum of 11 in deep in any flight of stairs.27. Tread width must also be consistent within each flight since varied widths can create optical illusions that affect the balance of users. Avoid confusing patterns on stairway floor coverings for the same reason.

To prevent people from walking into hanging stairways or other elevated protruding objects, install wing walls or curbs under them. Guardrails or planters could also be used.

On stairs, color contrast the edge of treads and risers so that the edges can be spotted more easily. This is especially important on the first and last steps. With self-illuminating strips, the edges can be seen in the dark. Also contrast the handrails from the wall so that they can be seen more quickly in an emergency.

Single stairs can be difficult to see and are dangerous when they are not expected or lighted properly. Many building codes do not allow their use, but when use is allowed, a change in texture or color on a single stair will help. Texture should also be used to mark stairway landings and other areas that are hazardous to people with differences in vision. Landings at exterior stairway entrances may become slippery when wet, so they must be slightly sloped (not exceeding 1:50) for drainage.

References
1. Uniform Federal Accessibility Standards, 24 CFR subtitle A 4 1 90 (Washington, D.C.: Government Printing Office, 1990).
2. Americans With Disabilities Act Accessibility Standards, 1991.
3. UFAS, 1990.
4. Department of Justice. "ADAAG for Buildings and Facilities; Children's Facilities; Proposed Rules" Federal Register July 22, 1996.
5. Hofstedt, Denise, ed. "Accessible Trails: Consistency Still a Question". Universal Design Newsletter April 1996, 2 (6), p. 8.
6. ADA Standards, 1991
7. Van der Voordt, D.J.M., "Accessibility by Means of Ramps", Proceedings of the Built Environment and the Handicapped: Toward a Normal Life for the Disabled and Elderly, (Gotheberg, Sweden: Swedish Council for Building Research, 1981), 38-40.
8. Van der Voordt, "Accessibility", 38-40
9. Robert Sorensen. Design for Accessibility. (New York: McGraw Hill, 1979), 158.
10. ADA Standards, 1991
11. National Center for Accessibility, 1997, "Swimming Pool Accessibility Project", Martinsville: NCA (800 424-1877)
12. American National Standards Institute, American National Standard for Buildings and Facilities Providing Accessibility and Usability for Physically Handicapped People, ANSI A117.1 1986 (New York: ANSI, 1986).
13. ADAAG 4.1.3 (5)
14. ADA Standards, 1991
15. Van der Voordt, Theo J.M. et. al., January, 1996. Checklist for Adaptable Renovation. Delft, The Netherlands: Technical University of Delft, Dept. of Architecture. (FAX 31 15 278-1028)
16. ADA Standards, 1991
17. North Carolina State Building Code Council, North Carolina State Building Code, vol. 1 C (Raleigh: NCSBCC, 1989).
18. NCSBCC, 1989.
19. NCSBCC, 1989.
20. NCSBCC, 1989.
21. ADA Standards, 1991
22. ADAAG 4.3.11
23. ADA Standards, 1991
24. NCSBCC, 1989.
25. ADA Standards, 1991
26. ADA Standards, 1991
27. ADA Standards, 1991

Excerpted from Beautiful Universal Design by Cynthia Leibrock and James Evan Terry; used with permission.
Copyright © 1999 by Cynthia Leibrock and James Evan Terry

Read more
For more information on financing your home remodel, see Financing an Accessible Home: How to Remodel and Stay Within Your Budget.

For other accessible lift options for your home, see Three Lift Options to Make Your Home More Accessible.