ADA Parking Slope in Plain English

Accessible parking and the access aisle are built nearly flat so a wheelchair does not roll. A commonly cited maximum is 2 percent, about 1/4 inch per foot. Check the current ADA Standards and the local official before you pave. Paint does not level a steep bay.

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What 2 percent looks like on a tape

Accessible parking and the access aisle are built nearly flat so a wheelchair user does not roll while getting into a vehicle. The figure people cite most often is 2 percent maximum slope in any direction on the stall and the access aisle. Two percent is 0.02. On a 12 inch foot, 0.02 times 12 is 0.24 inch, which is about 1/4 inch per foot. On an 18 foot stall length, 0.02 times 18 feet is 0.36 feet, about 4.3 inches of rise if the whole stall sat at that limit. That arithmetic helps you see the slope. It is not a ruling. Check the current ADA Standards and your local building official before you pave, because the number, the signs, and the markings are a legal design, not a blog opinion.

A steep lot needs a leveled bay

A lot can slope enough to drain and still be too steep for an accessible stall. Paint on that slope does not make it flat. The usual fix is a leveled bay: a small area graded to the flatness limit, with the rest of the lot sheet-draining around it. Ask the designer where that bay sits relative to the entrance, because a flat stall that is far from the door still fails the trip. The asphalt under the bay is real pavement. If the leveled area is 14 by 20 feet, that is 280 square feet. At 2 inches and 145 pounds per cubic foot, 280 times 2 divided by 12, times 145, divided by 2,000, is about 3.4 tons as a planning estimate. The plant ticket is the real weight. Grading, not the sealer, creates the flatness.

Measure before the paver leaves

Check slope in both directions, not only down the stall. A cross slope can hide while the length looks fine. Use a straightedge and a level, or a smart level, and write the percent down. If the fresh mat is already steeper than the limit the official told you to meet, the time to fix it is before the lot is striped. Milling a high spot or adding a thin level is a paving decision. Do not invent a variance in a blog. Ask the local official which edition of the standards applies and how they want the access aisle marked. Keep drainage so the flat bay does not become a pond. A birdbath in an accessible stall is its own failure, even when the average slope looks gentle.

A practical sequence

Read 2 percent as about 1/4 inch per foot, then confirm it in the current ADA Standards.
Ask the local official which rules apply before you pave the bay.
Level the stall and access aisle in both directions, not only with paint.
Plan the paved area at 145 pounds per cubic foot, and use the plant ticket as the real weight.

The mistake to skip

Striping an accessible stall on a slope and hoping the sign makes the bay legal.

Questions people ask

Is 2 percent the rule I can build from this page?

Two percent, about 1/4 inch per foot, is the figure commonly cited for an accessible stall and its access aisle so a wheelchair does not roll. Check the current ADA Standards and the local official before you pave. Markings and signs are part of that design. This page is a planning explanation, not a legal conclusion or a waiver.

Can sealcoat flatten a steep accessible stall?

Sealcoat is a thin film. It does not change slope in any meaningful way. A steep lot needs a leveled bay, graded and paved to the flatness the standard requires. Confirm that limit with the current ADA Standards and the local official. Any new asphalt tons are a planning estimate near 145 pounds per cubic foot, and the plant ticket is the real weight.

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