If a disability has made it difficult for someone in your family to navigate a flight of steps leading in and out of your home, it's time to consider installing a ramp.

You can get a pre-built ramp by looking in your phone directory under "Wheelchair Lifts and Ramps" and "Hospital Equipment." These all-purpose ramps, which are generally made of aluminum, may be fine for a temporary situation or one in which there are only one or two steps to bypass.

But if you have a greater number of steps and plan to use the ramp for a long time, you may need to have one constructed. This will require taking into account local building codes, the weather, how the ramp will look, the kind of usage the ramp will receive, and whether the strength or mobility of the person using the ramp is liable to change in the future.

Building a ramp yourself is recommended only for those who are rugged of body, knowledgeable about construction techniques, and who have the time (several days at least) and the skill to do the job right.

First you may want to try calling your local Independent Living Center to see if there are any community programs in your area that help families with special needs with the design, labor and/or the cost of building a ramp.

Whether you plan to do it yourself or hire professional help, you should also call your city or county and ask what building codes apply to the placement of ramps where you live.

RAMP BASICS

Exterior ramps can be made from a variety of materials, including metal, concrete and wood, but any exposed wood should be of a variety -- such as redwood -- that is able to withstand severe weather conditions. Allowance should be made for water to run off, so that an icy surface won't form in cold weather and general damage won't occur to the wood. Building a cover over an exterior ramp will definitely raise the cost, but could be worthwhile in areas with lots of snow and rain.

Planks should be laid out perpendicular to the direction the wheelchair travels, so that wheels won't get lodged in the gaps between the planks. The surface of a ramp needs to be rough and slip-resistant. This can be done using a variety of materials, ranging from rolled roof shingling to the kind of paint used on airplane exteriors.

For safety, there should be curbs along the sides of the ramp to prevent a wheelchair from wandering over the edge. Easy-to-grip handrails are also recommended for some in wheelchairs and for anyone who is ambulatory but uses a ramp; rails made of wood are easier to hold onto than metal ones in extreme weather. Ramp width can vary; 4 feet might be good but other factors might require greater or lesser width.

If the old steps are blocked by the ramp, new, available steps should be incorporated in the ramp design.

To reach an entrance 3 feet above the ground, a ramp with an ADA-prescribed 1:12 slope would have to be 36 feet long. A more gentle 1:20 slope would require 60 feet of length to reach the same height. Level landings should be used between ramp segments in both cases.

RISE OVER RUN EQUALS SLOPE

Perhaps the most important consideration is the slope, which is determined by ascertaining the "rise" -- the straight vertical distance a person will travel when going up or down a ramp -- versus the "run," which is distance measured along the ground from one end of the ramp to the other. The ratio of rise over run gives you the slope. (A measurement taken up the sloping surface of the ramp is something else entirely.)

A 1:12 slope is one in which the ramp builder must allow 12 feet of horizontal extension for 1 foot of vertical height. (It's not important whether the measurement is in feet, inches or centimeters, but rise and run are usually expressed in one of these units.) Many people confuse the fact that a 1:20 slope is less steep than a 1:12 ramp. The larger the second figure, the more gentle the slope.

The ADA mandates that ramps in public places must not be steeper than 1:12, and that's generally found to be a good guideline in building ramps on homes. But while a 1:12 slope may be OK for a person in a motorized wheelchair, it may be tough for a manual wheelchair user. A more gentle 1:16 or 1:20 slope may be in order.

The downside of building an easy, gradual slope is that it requires a greater amount of distance extending out from the home. If your front door is 3 feet off the ground, per the 1:12 slope ratio you'd need to have a ramp extending 36 feet. A more gradual slope would need to be even longer. But what if there's only 20 feet from your front door to the street or driveway, or if there's something in the front yard such as a tree or a garden that you can't bear to disturb?

A designer may be tempted to lessen the run by making the ramp steeper, but that's almost always the wrong choice. A ramp that's too steep may require too much muscle power for those in manual chairs, or for those pushing them, and a power wheelchair can topple backwards from its own weight.

TWISTS AND TURNS

One way to address the length problem without increasing the slope is to build turns into the ramp, making it in an "L" shape or even making a "switchback ramp," one which includes at least one 180-degree turn.

The modular method of ramp building allows for ramp segments to be assembled off-site and makes for quicker construction. Almost any group of volunteers can do the job if supervised by a professional. (Photos in this article are courtesy of the Metropolitan Center for Independent Living in St. Paul, Minn.)

When turns are included, the ramp must level off at a landing large enough to allow a wheelchair to turn with ease, and then a new ramp segment continues in a new direction. The landing at each turn should be at least 5 feet by 5 feet.

Another landing is necessary at the top of the ramp by the door to the house. Without it, the person in the wheelchair is in danger of slipping back down the ramp while trying to get the door open. The height difference between the top of the ramp and the door shouldn't be more than half an inch. The same is true for the distance between the bottom of the ramp and the ground.

Even without turns, a ramp segment shouldn't extend more than 30 feet without stopping for a landing. "You don't want to go on a continuous slope for more than that," says Bob Zimmerman, an independent living counselor with the Minnesota Division of Rehabilitation Services. "Some people want a rest spot every 15 feet. That's where you have to examine the needs of the individual."

"The most important part of access design is considering the person's total situation in order to come up with the best solution," Zimmerman says. "Sometimes ramps are not the best choice and looking at lifts or other options is important. If you don't have the room, a lift may be your only choice."

Also, the location of the ramp -- front door, back door or elsewhere -- is an important consideration that needs to be carefully thought out.

CREATIVE SOLUTIONS

In 1992, Zimmerman worked with the Metropolitan Center for Independent Living in St. Paul to develop a statewide program called the Minnesota Ramp Project, which employs a special, easy-to-install modular ramp design. The modular design allows ramp segments to be built off-site prior to construction, and disassembled and reused elsewhere later.

"Having a structure that can be used as long as needed and then easily removed for reuse at another location gives people some control of their situation," Zimmerman says.

For some people long-tread, low-riser steps are easier to use than a ramp. The red markers on each step are depth perception aids that help guard against tripping.

There is an alternative to ramping called long-tread, low-riser steps. These are specially built steps that are much more gradual than normal and much easier to use, and may be a good idea for people with walking difficulties who are still ambulatory. They aren't appropriate for wheelchair users.

"The benefit is that your feet stay level at all times, so your balance is not affected," says Zimmerman, who has built these kinds of steps for people in early stages of ALS, while allowing for the possibility that the steps might eventually have to be replaced with a ramp for wheelchair use.

"We recently installed a set of modified steps in the home of a 3 1/2-year-old boy who has spinal muscular atrophy. He and his family live in a multi-level home and his parents had to carry him up and down the steps to the garage. Now he uses the new steps all by himself and is immensely proud of his ability to do so."

FAMILY ISSUES

"Children love to play on ramps," says Gail Bouchee, Home Access Program Coordinator at Direct, an Independent Living Center in Tucson, Ariz., that helps provide ramps to low-income families. "They become a piece of jungle gym equipment, and then the family is upset because the ramp doesn't hold up. They're not designed for baby carriages and bicycles and wagons and everything else, or for kids to be swinging from them. That can be a problem sometimes.

"We have ramps that are going on 10 to 12 years, generally when the families have been good about doing some routine maintenance and painting," Bouchee says.

For additional information about ramps and ramp-building programs, write to DIRECT Center for Independence, 1023 N. Tyndall Ave., Tucson, AZ 85719-4446, or call (520) 624-6452 (VOICE or TDD).

Bouchee notes that family issues must be taken into account when she counsels someone about adding a ramp or other home modification. "Sometimes Dad doesn't want to build the ramp under the carport because he works on his car out there," she says. "We try to explain the things that families need to think about, and then give them a little space so they can sit down as a family and say, what are we going to have to compromise?"

For Bouchee, the most gratifying feedback she gets is when she calls a client and asks if she can come and see how their new ramp looks. "And they say, sure, come right over, but I'm not going to be here, I have to leave. That's thrilling to me, because it means now they're in a position to go out, get to school, or do whatever they need to do. They'll take this opportunity and move on with their lives."