The short answer
A dock leveller is a steel platform set into a loading bay at the door, which rises or falls to meet the bed of a trailer and rests a hinged or sliding lip on it. It lets forklifts and pallet trucks drive straight between the warehouse floor and the vehicle, whatever the trailer's height.
On this page
Why loading bays need one
A warehouse loading dock is usually built with its floor around 1.2 m above the yard, so that it lines up roughly with the bed of a lorry trailer. Roughly is the problem. Trailer beds vary with the make, the suspension, the tyres and the load, and they sink as a forklift drives on. Without something to bridge the step and the gap, every pallet goes over a lip that can tip a load or jolt a driver.
A dock leveller closes that gap. It sits in the floor right behind the dock door, level with the warehouse floor when it is not in use. When a trailer backs on, the operator raises the platform, the lip swings or slides out, and the platform lowers until the lip rests on the trailer bed. The result is a gentle ramp that moves with the trailer as it is loaded.
The main types
Hydraulic swing lip
The most common leveller in UK warehouses. An electro-hydraulic power pack raises the platform, the hinged lip swings out at the top of the stroke and the platform lowers onto the trailer. One button, a few seconds. It handles curtain-siders and box trailers well and is the default choice for general distribution.
Hydraulic telescopic lip
The lip slides out instead of swinging, so the operator can place it exactly where it is needed, even a short way into the trailer. That suits end-loaded trailers, cold stores where the last pallet sits right at the back doors, and loads that do not like being bumped.
Edge-of-dock
A short plate bolted to the face of the dock with no pit. It is the cheapest and quickest to fit and suits sites where the trailers are always close to dock height. It cannot cope with large height differences.
Mechanical and air-powered
Spring-loaded mechanical levellers and air-bag levellers exist and are common in some markets, but most new UK installations are hydraulic.
Size and capacity
Levellers are specified by platform length, platform width and capacity.
| Choice | Typical options | What it affects |
|---|---|---|
| Length | About 2 m to 4.5 m | Longer gives a gentler slope over the same height difference |
| Width | About 2 m, wider for some uses | Clearance for pallets and trucks at the trailer edges |
| Capacity | Commonly 6 tonnes, often more | Must cover the truck, its load and the impact of driving on |
The slope matters most. Low pallet trucks and heavily laden forklifts struggle on steep ramps, so the length is chosen from the biggest height difference the dock sees and the gradient the equipment can manage.
Shelters, seals and the door
A leveller rarely works alone. Above it sits the dock door, usually an insulated sectional door. Around the opening there is either a dock shelter (a frame with fabric curtains that close around the trailer) or a compression seal (foam pads the trailer pushes against). Bumpers on the dock face protect the building from reversing trailers. Together they make up a loading bay, and they are best specified as one package.
Safety
The most serious loading bay accident is a vehicle moving while a forklift is on the leveller, either because the driver pulls away early or because the trailer creeps forward under the forces of loading. HSE guidance sets out ways to stop it, from wheel chocks and a key or traffic light system to engineered trailer restraints and interlocks that stop the door opening until the vehicle is held. Many large operators now require a restraint at every bay.
The leveller itself needs toe guards on its sides, a working emergency stop and a maintenance free-fall valve that stops the platform dropping if a hose fails. Because a leveller is work equipment, it must be kept in good repair under the Provision and Use of Work Equipment Regulations 1998, which in practice means a planned service, often every six months, and daily checks by operators.
What one costs
A hydraulic pit leveller is typically £6,500 to £12,000 installed before VAT, and an edge-of-dock unit £1,700 to £3,600, with shelters, seals and new pits on top. The dock levellers page breaks these down per loading position, and the industrial door cost calculator prices a full set of bays with their doors.
If you are planning new bays or replacing worn levellers, describe the site and we will find a loading bay specialist who covers your area.