A ramp that is too steep isn’t a minor inconvenience — it can turn a "solution" into a hazard, tipping a manual chair backwards on the push up or letting a powered chair run away on the way down. Yet gradient is the one spec that gets skipped most often when someone buys a portable ramp online or asks a builder to "pop a slope in" by the front door. Before you spend money on a ramp, or agree a quote for one, here is what UK guidance actually says the gradient should be — and why the answer depends on more than just how steep the drop is.
What "gradient" actually means for a ramp
Ramp gradient is expressed as a ratio of rise to run — for example, 1:12 means the ramp climbs 1 unit of height for every 12 units of horizontal length. The smaller the second number, the steeper the ramp. It sounds like a small detail, but the difference between 1:12 and 1:20 is the difference between a ramp a self-propelling wheelchair user can manage alone and one that requires someone pushing from behind.
In the UK, ramp gradients for permanent installations are set out in Building Regulations Part M (Access to and Use of Buildings) — Volume 1 covers dwellings, Volume 2 covers buildings other than dwellings — and echoed in BS 8300:2018, the British Standard for accessible and inclusive design. Part M is a legal requirement for new or altered buildings; BS 8300 is best-practice guidance that generally aligns with it. Separately, the Equality Act 2010 requires reasonable adjustments to be made so disabled people are not put at a substantial disadvantage — which is often the practical reason a ramp gets installed at all.
The gradient numbers, and why they change with distance
There isn’t one single "correct" gradient — it depends on the building type and how much height the ramp needs to overcome. As a general guide for permanent ramps in non-dwellings:
| Gradient | Maximum rise per flight | Maximum flight length |
|---|---|---|
| 1:12 | 166mm | 2m |
| 1:15 | 333mm | 5m |
| 1:20 | 500mm | 10m |
The pattern is straightforward: the steeper the slope, the less height it’s allowed to cover before a level rest landing is required. For public buildings, 1:12 is generally treated as an absolute maximum reserved for very short rises where space genuinely doesn’t allow anything shallower — the preferred gradient is 1:15, or 1:20 where there’s room, because a shallower slope is manageable by a far wider range of wheelchairs and mobility scooters. For dwellings, the guidance is stricter still: 1:20 is generally the recommended maximum for a new permanent domestic ramp, not just the preferred option.
Portable ramps sold for home use sit in a slightly different category — they aren’t governed by Building Regulations in the same way, but British Standards guidance still applies a 1:20 to 1:12 range as sensible, with steeper gradients such as 1:8 considered acceptable only with an assisting carer or for a powered wheelchair, and only after a proper risk assessment. A steep portable ramp bought on gradient alone, without checking who will actually be using it and whether they’ll be alone, is a common and avoidable mistake.
Width, landings and handrails: gradient is only part of the sizing job
Getting the slope right doesn’t make a ramp safe on its own — three other measurements matter just as much:
Width. In public buildings the clear width should be at least 1500mm, wide enough for a wheelchair and a pedestrian to pass safely; an unobstructed 1.8m is recommended where two wheelchair users need to pass each other. For a private home, 900mm is the standard minimum width, rising to 1200mm for shared or communal access.
Landings. A level landing is required at the top and bottom of every ramp, at least 1200mm long and kept clear of any door swing. Where a ramp is long enough to need an intermediate landing — because no single flight should run further than 10 metres or rise more than 500mm — that landing should be at least 1500mm long, widening to 1800mm x 1800mm where there are three or more flights, so that two chair users have room to pass.
Handrails. Handrails are compulsory on both sides of any ramp steeper than 1:20, fitted between 900mm and 1000mm above the ramp surface and extending at least 300mm beyond the top and bottom of the slope. Where one side of the ramp is open — not bounded by a wall — edge protection such as a raised kerb is also expected, to stop a wheel running off the side.
Why this matters more than the price tag
Consumer advocacy in health has always meant the same thing: asking whether a product actually does what the buyer needs, not just what the seller claims. A ramp is no different. A steep, narrow ramp bought because it was the cheapest option on a listing can leave someone permanently dependent on a helper to get in and out of their own home — the opposite of what a mobility aid is supposed to achieve. Before buying or commissioning a ramp, measure the actual rise you need to cover, work out the flight length the gradient tables above imply, and check that width and landing space are realistic for the space available — not just for the ramp on its own, but for the door swing, the turning circle, and anyone who might need to pass another person on it.
If a supplier or installer can’t tell you the gradient ratio they’re proposing, or brushes off questions about landings and handrails, treat that as a warning sign rather than a technicality. Getting the sizing right the first time is what turns a ramp from a compliance box-tick into something that genuinely restores independence.