DDA Ramp Requirements: Gradient, Width, Landings and Handrails

A ramp built for public access needs a maximum gradient of 1:15, a clear width of 1200mm or 1500mm, a level landing at the top and bottom, and an intermediate landing every 5 metres of slope. Miss any one of those and the ramp isn’t compliant, however well it’s put together.

This is the specification most contractors and building owners come to us with half-finished. They know they need step-free access. They know it’s a legal duty. What they don’t have is the set of dimensions the ramp has to hit before anyone orders steel. Below is each requirement, what it means in practice, and the components that meet it.

What Makes a Ramp DDA Compliant

“DDA” is trade shorthand that has outlived the law it refers to. The Disability Discrimination Act 1995 was replaced by the Equality Act 2010, which is the legal basis today. The Act requires building owners and businesses to make reasonable adjustments to remove physical barriers that stop disabled people using a building.

The Act tells you that you have a duty. It doesn’t tell you what the ramp has to measure. That comes from two documents:

• Building Regulations Approved Document M: Access to and use of buildings. Statutory guidance covering ramp gradient, width, landings, handrail dimensions, grip and colour contrast.
• BS 8300, the British Standard on designing an accessible and inclusive built environment.

Read them together. Approved Document M is the compliance floor for building work; BS 8300 carries the design detail. A ramp specified against both, and installed correctly, is what “DDA compliant” means in practice.

Gradient: 1:15 Maximum for Public Access

The gradient is the number that decides everything else about the layout. For public access, specify a maximum of 1:15: one metre of rise for every fifteen metres of run.

That ratio has a consequence people underestimate. A 600mm rise at 1:15 needs 9 metres of ramp before you add a single landing. Add the top and bottom landings and the intermediate landing that a 9-metre run requires, and the footprint grows again. This is why ramps switch back on themselves: the gradient dictates the run, and the site rarely has it in a straight line.

Approved Document M sets gradient limits in relation to the length of each ramp flight, so confirm the figure permitted for your specific flight lengths before the layout is signed off. Steeper is not a shortcut. A ramp too steep for a self-propelling wheelchair user is not an adjustment, it’s an obstacle.

Width: 1200mm or 1500mm

We supply DDA compliant ramps in two standard clear widths.

1200mm is the standard specification for public use. It gives a wheelchair or mobility scooter a clear route with room either side of the wheels.

1500mm is the width to specify where a carer needs to walk alongside the user, where two-way movement is likely, or where the ramp serves a building with high footfall, such as a school entrance, a GP surgery or a care home. If the site has the space, the wider ramp is the better adjustment.

Clear width means clear. Measure between the inside faces of the guarding, not the outside of the frame. Handrails, toeboards and infill panels all sit inside the structural envelope and all of them eat into the usable route if the ramp is specified on the wrong dimension.

Landings: Top, Bottom, and Every 5 Metres

Three landing rules apply to a compliant ramp:

1. A level landing at the top. So a wheelchair user can stop, hold position and operate the door without managing the slope at the same time.
2. A level landing at the bottom. So the user can come off the ramp onto flat ground before turning.
3. An intermediate landing every 5 metres of slope. A rest point on any run longer than 5 metres.

Landings are also where a ramp changes direction. Where the site won’t take a straight run, the layout turns at a landing, which is why the intermediate landing rule and the switchback layout tend to solve each other.

Tight sites are the common problem here, and they’re solvable. Send us the levels and the available footprint and we’ll work the layout back from the landings.

Handrails: 42.4mm Diameter, Continuous Run

The Building Regulations recommend a handrail outside diameter of between 40mm and 45mm. Our DDA handrail range is built around 42.4mm o/d tube (size 7 in trade sizing), which sits in the middle of that band and gives a grip section a hand can close around properly.

The handrail has its own rules: see DDA handrail requirements and why the handrail must be continuous.

The second requirement is continuity. The DDA range uses purpose-made fittings so the handrail runs as one smooth line from the bottom of the ramp to the top, with no intermediate upright posts breaking the run. That matters most to a visually impaired user, who can follow the rail its full length without meeting an obstruction.

The fittings that make that possible are specific:

One installation note that matters: the internal fittings (DDA725, DDA09 and A9) sit inside the tube, so they need medium weight tube with a maximum wall thickness of 3.2mm.

Handrails are supplied hot dip galvanised as standard. They can be powder coated to RAL standard colours, subject to quantity and availability. It is worth specifying, because a powder-coated rail gives the impression of being warmer to the touch in cold weather, and colour contrast against the background helps users with limited vision find the rail.

Guarding and Loading

Where the ramp is raised, guarding does a different job from the handrail. Our systems are compatible with Building Regulations Part K (Protection from falling, collision and impact) and Part M, and are designed, like our key clamp handrail kits, for the loading categories typically applied to public barriers: 0.74 kN/m and 1.5 kN/m. Standard barrier height for most public applications is 1100mm. BS 6180 covers barriers in and about buildings and is the standard to check your loading category against.

Three guarding components are worth specifying at design stage rather than adding later:

• Toeboard edge guards stop a wheel or a walking aid running off the edge of the ramp.
• Vertical bar infill panels are anti-climb and appropriate where children use the building.
• Child-height rails add a second, lower rail where the ramp serves a school, nursery or family setting.

Surface: Slip Resistance, Drainage and Contrast

An outdoor ramp is a wet ramp for a good part of the British year, and a slippery ramp defeats the point of building it.

Our ramps use a GRP (glass reinforced plastic) walkway with grit built into the surface and drainage holes through the panel. Water and ice drain rather than sitting on the slope, so the surface performs across the seasons rather than only in dry weather.

Panels can be colour contrasted to help users with visual impairments read the edge of the route and the transition onto each landing. Contrast is a genuine accessibility feature, not a finish option: Approved Document M treats visual contrast as part of accessible design.

The frame is galvanised steel, hot dip galvanised to BS EN ISO 1461. It resists rust and moss and needs very little maintenance, which is the practical difference between a steel ramp and a timber one after five winters.

Why Modular Steel Rather Than Concrete or Timber

The ramp has to be compliant. It also has to be built, on a live site, usually around an entrance that has to stay open.

Our ramps are assembled from tubular key clamp fittings and galvanised tube. That has four consequences on site:

No welding and no hot works. Assembly needs a hex key. No hot work permit, no welder, no fabrication shop.

No heavy groundwork. Load-bearing feet adjust on site to take up level changes, rather than requiring a poured foundation.

Adaptable around what’s already there. Doorways, uneven ground, changing levels and awkward corners get designed around rather than dug out.

Reversible and extendable. A modular ramp can be modified, extended or taken down and rebuilt. A concrete one can’t. On a leased building, that’s often the deciding factor.

A standard ramp can be assembled in around a day by your installer, depending on the design. See a wheelchair access ramp handrail project for how it goes together on site. We supply the ramp; the fitting is done by you or your contractor.

Where the Duty Sits

Worth being plain about this, because it’s the part suppliers usually leave vague.

The Equality Act 2010 duty to make reasonable adjustments sits with the building owner or occupier. On a construction project, the duties under CDM 2015 sit with the client and the contractor. As a supplier, we provide product to a specification, with technical data, and test reports available on request. We don’t take on the duty-holder role.

What that means practically: a compliant ramp is a correctly specified ramp that has been correctly installed. Get the specification right, use an installer who follows it, and keep the paperwork. If you want the Health and Safety Executive or Approved Document M checked against your specific layout, do it before the steel is ordered rather than after.

Specifying and Ordering

We’ve supplied ramps and access handrails since 1912, from stock, from our Worcester warehouse. Ramps are used across GP surgeries, schools and libraries, retail and commercial entrances, care homes and supported housing, offices and workplaces, and private homes needing step-free access.

What you get from us:

• A free design service at layout level. Send us your levels, footprint and door position and we’ll configure the ramp and the kit list around them.
• Quotes within one hour during working hours.
• Next-day delivery on the majority of stock orders, with most ramps despatched within days of order.
• Free cutting: tube cut to length before despatch, so it arrives ready to assemble.
• Test reports on request and technical data with every component, with spec sheets on our brochures page.

Send us your site levels and entrance dimensions and we’ll come back with a layout and a quote. Request a quote or call the sales office on 01905 779944.

DDA Ramp Requirements FAQs

What Gradient Does a DDA Compliant Ramp Need?

A maximum of 1:15 for public access: one metre of rise for every fifteen metres of run. Approved Document M sets gradient limits in relation to ramp flight length, so confirm the permitted figure for your specific flight lengths before finalising the layout.

What Width Should a Wheelchair Access Ramp Be?

We supply two standard clear widths: 1200mm, which is the standard specification for public use, and 1500mm for sites where a carer walks alongside the user or where two-way movement is likely. Measure clear width between the inside faces of the guarding, not the outside of the frame.

How Often Does a Ramp Need a Landing?

A level landing is required at the top and at the bottom of the ramp, plus an intermediate landing every 5 metres of slope. Landings are also where the ramp changes direction, which is why longer ramps switch back rather than running straight.

What Diameter Should a DDA Handrail Be?

The Building Regulations recommend an outside diameter of between 40mm and 45mm. Our DDA range is built around 42.4mm o/d tube (size 7 in trade sizing) and uses purpose-made fittings so the rail runs continuously with no intermediate uprights breaking the line.

Why Does a DDA Handrail Need to Be Continuous?

So a visually impaired user can follow the rail from one end of the ramp to the other without meeting an obstruction. Intermediate upright posts breaking the run interrupt that, which is why the DDA range connects the rail through purpose-made brackets rather than around posts.

What Surface Do Your Ramps Use?

A GRP (glass reinforced plastic) walkway with grit built into the surface and drainage holes through the panel, so water and ice drain rather than sitting on the slope. Panels can be colour contrasted to help users with visual impairments read the edge of the route.

How Quickly Can a Ramp Be Assembled?

Assembly is key clamp and hex key, with no welding or hot works, so a standard ramp can be assembled in around a day depending on the design. We supply the ramp, the fittings, the tube cut to length and the layout.

What Standards Do Your DDA Ramps and Handrails Work To?

Ramps are specified against Building Regulations Approved Document M and BS 8300, with the legal basis being the Equality Act 2010. Guarding is compatible with Approved Document K at the 0.74 kN/m and 1.5 kN/m loading categories, at 1100mm standard barrier height. Steelwork is hot dip galvanised to BS EN ISO 1461. Test reports are available on request.