By Paul Bianchina
For many homes and businesses, easy accessibility for people in wheelchairs or who walk with limited mobility is an important issue. The answer in virtually every instance is to install an accessibility ramp, but there are a few construction rules you should know about to make sure you get it built correctly.
Building Code Requirements
The most important thing to bear in mind when planning and constructing a ramp is the slope. Having a ramp that is too steep will be difficult to use, while having one that is too flat will use up unnecessary space and materials in its construction.
Most of the building codes require that egress ramps - ramps that are used to get people into and out of a building - have a maximum slope of "one unit vertical in eight units horizontal (12 percent slope)". The units can be feet, inches or any other measurement, so long as it's consistent.
For example, suppose you have a front porch that is two feet high, and you would like to build a ramp up to it. The unit of measurement is feet, so to climb two feet in height the ramp should be 16 feet in length (2 units x 8 units). If space is an issue, the building officials may make provisions for the construction of a slightly steeper ramp, but that's an individual, case-by-case decision and again, the ramp can't be allowed to be too steep or its usefulness will be affected.
The entire ramp does not need to be constructed in one straight line, although that's obviously the easiest to build and the easiest to use. In the case of the 16-foot ramp above, you could, for example, go eight feet in one direction, turn 180 degrees, and go eight feet in the opposite direction, plus any additional length needed to make the turn. Another example would be to go 10 or 12 feet in one direction, turn 90 degrees, and finish out the last four to six feet in that direction. There are a number of possible combinations.
In addition to the overall length of the ramp, the building codes also require that you provide a landing "at the top and bottom of ramps where doors open onto the ramp and where the ramp changes direction." Landings must be level, and a minimum of 3'x3' in size. This also means that the ramps themselves must be a minimum of three feet wide.
The final building code requirement is for a handrail. Most codes state that "handrails shall be provided on at least one side of all ramps exceeding a slope of one unit vertical in 12 units horizontal (8 percent slope)." Typical handrail requirements are for wood or metal railings between 30 and 38 inches high - there are a number of additional construction requirements, so talk with your building department for specifics before beginning construction.
Construction Materials
If you're looking for a ramp that is sturdy, weather-resistant and virtually maintenance free, the best material is concrete. The standard course of construction for a concrete ramp is to lay-out and pour the flat landings first - this gives you an accurate measure of size and slope for the overall ramp.
After the landings are done, angled forms are constructed between them for the ramp itself. Depending on the steepness of the ramp, cross forms are often installed every four to six feet and the concrete is poured in stages, making it easier to screed and finish the concrete on a slope without it all flowing to the bottom of the ramp forms. A light broom finish is often placed on the fresh concrete to provide a slip-resistant walking or rolling surface.
To soften the appearance of the concrete ramp and to blend it in with the building a little better, you can cover the sides with another material. Wood siding can be used as long as the top edge of the siding is protected from the weather, which would quickly deteriorate the wood, or you can use brick or stone veneer. Plants can also be used in front of the ramp's vertical surfaces to soften and conceal it, but remember to keep all plants trimmed back so that they don't grow onto the ramp and interfere with the walking surfaces.
Wood is also a common material for ramp construction, especially for a residence. Ramps are built in much the same manner as a deck is built, using 4x4 or 4x6 pressure-treated lumber on concrete piers for the main support posts, and 2x6 or other 2x lumber for the joists and other framing.
Plywood is the most common choice for the ramp covering, since it's sturdy, smooth and easy to install. If you choose to paint the ramp, remember to prime the wood first, and then to use a good-quality porch and floor enamel with a slip-resistant additive for the ramp surfaces.
Remember that ramps require a building permit, and the construction specifications can vary widely between jurisdictions. Always consult with your local building department prior to starting work.
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