Top Landings: Top landings should be nearly flush with the exterior door threshold. 1/2" is the typical maximum, particularly when a wheelchair user is involved-anything larger will abruptly stop a chair's relatively small front wheel, or is a tripping hazard for walkers. Pay attention, too, to threshold specs if a new primary door is being installed. If a prehung unit's going in, most don't have the low threshold that's needed here.

For homes on footed foundations, it's advisable in most parts of the state to bolt the top landing into the home's foundation. This will avoid the potential problem of the relatively lightweight ramp landing lifting up due to frost heave and jamming under an outswinging door (like a storm door). For unfooted structures, or temporary foundations such as mobile homes on blocks, bolting the landing may still be appropriate, but the ramp shouldn't be footed for the opposite reason. Local soil conditions -e.g., clay vs. loam- will also play a definite role here.

Top landings at minimum should be at least 60" X 60" if there is an outswinging door, with at least a 12" to 24" of "elbow room" space provided off the door's handle side, particularly for a person using mobility equipment. These dimensions give enough room for a person to move off to the side while opening the door without having to back up to get out of the way of its swing. If there is no outswinging door, the landing may be somewhat narrower- probably 48" at minimum.

Intermediate Landings: Intermediate landings for a long, in-line run of ramp can have the same width as the running surface's, and length can range from 36 " to 60"-the slope chosen is a factor to account for here, with a steeper slope like a 1:12 requiring a longer distance in which to stop when descending. A rough guideline to use is to install an intermediate landing if a section of ramp covers more than a 30" change in rise, but persons with limited stamina/control may need one sooner than this. Dimensions for intermediate landings where a direction change occurs depend on ramp width and the user's circumstances. When a chair user's involved, a 48" X 48" landing for a 90 degree turn is comfortable; for an 180 degree turn, 48" by twice the width of the two ramp sections is typical.

Bottom Landings: For bottom landings, typical minimum dimensions when in-line travel is involved are as wide as the ramp by about 48" long for someone walking, and about 60" to 72" for a chair user. Larger-width landings may be called for if the person has to make a direction change (e.g. 90-degree turn). Make sure the ramp/landing intersection doesn't have a "lip" greater than 1/2" which would become a tripping/rolling hazard.