What is the steepest gradient allowed for a ramp?
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1:12 is the steepest gradient in Approved Documents K and M, and only for short flights. Each flight is limited by gradient: 1:12 allows a 2m going (166mm rise), 1:15 allows 5m (333mm rise) and 1:20 allows 10m (500mm rise), with gradients in between interpolated.
What is 1:12 as a percentage or angle?
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1:12 is 8.3%, or about 4.8 degrees. 1:15 is 6.7% (3.8 degrees) and 1:20 is 5% (2.9 degrees).
How wide does a ramp need to be?
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For non-domestic buildings, Approved Documents K and M ask for a surface width of at least 1500mm. In dwellings, Approved Document M asks for 900mm for M4(1) and private M4(2) approaches, and 1200mm for communal M4(2) and M4(3) approaches.
How long should ramp landings be?
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In non-domestic buildings, top and bottom landings should be at least 1200mm long clear of any door swing, and intermediate landings at least 1500mm long. Where a ramp has three or more flights, or users can't see from one end to the other, intermediate landings should be 1800 × 1800mm passing places.
When do I need steps as well as a ramp?
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Approved Document M Volume 2 asks for steps in addition to the ramp where the total rise is more than 300mm, and for a lift or other alternative where the rise is more than 2m.