Quick answer: What makes a loading dock system work for container unloading?
A loading dock system for container unloading requires a dock leveller long enough to manage the height difference between the dock and the container floor, typically a 10-foot (3-metre) platform. The leveller type, lip configuration, and dock door must all be matched to the container height, delivery configuration, and storage environment.
Most facility teams only start thinking about the loading dock once something goes wrong: the leveller doesn’t reach, the door leaks, or product gets damaged during unloading. Andrew Suckling, a dock systems specialist at Ulti Group, thinks about it before any of that happens. In this video, Andrew walks through a live loading dock system set up for container unloading at a major distribution facility in Auckland, explaining in plain terms why each element was chosen and what happens when it isn’t.
Here’s a breakdown of what he covers.
When containers meet docks, height matters
Why is container height at the dock important? Containers on trailers sit higher than standard rigid trucks at the dock face. In New Zealand, the floor height difference across common vehicle types can vary significantly depending on the trailer configuration. Getting the dock leveller size, gradient, and door clearance right for your actual vehicle type is what determines whether the dock performs safely and efficiently day to day.
A container on a trailer doesn’t sit at the same height as a standard truck. Andrew observes on-site that containers typically sit around 300mm higher at the dock face, and that single difference affects everything: the leveller you need, how you seal the gap, and whether the container doors can even open cleanly.
At this facility, that extra height has a practical upside. The container doors swing in across the top of the concrete dock apron, opening inside the building rather than out in the yard. That keeps the loading environment controlled – particularly useful for export operations where the container needs to be sealed on-site before the truck leaves.
Getting the dock leveller size right
This is where facilities often get caught short.
Because the container floor sits higher than the dock, the gradient of the dock leveller becomes critical. The facility in the video runs a 10-foot (approximately 3-metre) Horizontal Storing Dock Leveller from our dock leveller range. That longer platform is what keeps the slope across the transition manageable for forklift operators.
Specify a leveller that’s too short for the height differential, and the gradient steepens – product can tip and the crossing becomes unsafe for the forklift operator. That’s not an edge case. It’s a daily operational risk that gets locked in the day the concrete is poured.
Key takeaway
Leveller length determines gradient – and gradient determines safety
The longer the dock leveller platform, the more gradual the slope between the dock and the container floor. A 10-foot (approximately 3-metre) platform is commonly used where containers sit significantly higher than the dock. Get this wrong and the gradient steepens – increasing the risk of product tipping and creating an unsafe crossing for forklift operators.
Hinge lip or telescopic lip?
The system at this facility uses a hinge lip leveller – the platform drops and the lip swings out to bridge the gap onto the container floor.
But containers don’t always arrive in the same position. Andrew points out that when a container sits further back on the trailer, not flush with the rear edge, a telescopic lip leveller is the better option. The lip extends out to reach the container regardless of where it sits on the trailer. Which type suits your operation comes down to how your deliveries arrive.
Why this works for dry store – and why cold store is different
Andrew flags something that’s easy to miss at design stage: this dock configuration is well suited to dry storage, but it’s not the right choice for cold store.
When a leveller sits elevated to meet a high container floor, sealing the gaps underneath becomes more difficult. For an ambient dry store, that’s manageable. For a cold store operation, every unsealed gap is an energy loss and a cold chain risk. Cold store docks typically need a different leveller type, one designed for full environmental sealing from the outset.
Sectional doors vs standard roller shutters
The dock in the video is paired with an Insulated Sectional Door on a high lift track. The door travels upward before folding horizontal, keeping the internal space clear and unobstructed.
Andrew’s case for choosing a sectional door over a standard roller shutter comes down to two things: seal and insulation. A sectional door closes with a full perimeter seal. A standard roller shutter doesn’t seal as tightly, and without insulation, heat builds at low level when the door faces direct sun. For a dry store distribution operation running containers in and out all day, it’s the right door for the job.
| Feature | Insulated Sectional Door | Standard Roller Shutter Door |
|---|---|---|
| Sealing | Full perimeter seal | Less effective seal |
| Insulation | High-density insulated panel core | Not insulated (standard model) |
| Heat management | Controls heat gain through door face | Can allow heat build-up at low level when sun-facing |
| Best suited for | Controlled environment, dry store, dock applications | General security, low-environment-control applications |
| Track configuration | High lift, vertical lift, or standard lift options | Rolls up above opening |
FAQ’s
Why does a container sit higher than a standard truck at the dock? Containers on trailers have a higher floor height than standard rigid trucks. At a loading dock, this height difference affects the dock leveller size needed, the gradient of the transition ramp, and whether container doors can open cleanly inside the building. Choosing equipment that accounts for the actual vehicle height is what determines whether the dock performs safely.
What size dock leveller do I need for container unloading? A 10-foot (approximately 3-metre) dock leveller platform is commonly used where containers sit significantly higher than the dock floor. The longer the platform, the more gradual the slope — which reduces the risk of product tipping and creates a safer transition for forklift operators. The right size depends on the specific height difference at your dock.
What’s the difference between a hinge lip and a telescopic lip dock leveller? A hinge lip dock leveller extends a fixed lip out to bridge the gap between the dock and the trailer. A telescopic lip dock leveller extends further — useful when a container sits further back on the trailer rather than at the rear edge. Both suit container loading; the best choice depends on your delivery configuration.
Is a horizontal storing dock leveller suitable for cold storage? Not typically. A Horizontal Storing Dock Leveller at elevated height — used for container-on-truck loading — makes it more difficult to seal the gaps beneath the leveller. In dry storage, that’s manageable. In cold store environments, every unsealed gap creates energy loss and cold chain risk. Cold store docks generally require a different leveller type designed for full environmental sealing.
Why choose an insulated sectional door over a standard roller shutter for a loading dock? An insulated sectional door provides a full perimeter seal and thermal insulation. A standard roller shutter door seals less tightly and, without insulation, allows heat build-up at low level when the door is sun-facing. For distribution and dry store environments where environmental control matters, a sectional door is the more effective option.
What are the benefits of opening container doors inside the building? Opening container doors inside the building keeps the loading environment fully controlled — from the moment the truck backs in to when it leaves the dock. This is particularly valuable for export operations, where the container is sealed on-site before departure. It also improves security and reduces weather exposure during the loading process.
What is a high lift sectional door track? A high lift track is a configuration where the sectional door travels upward before folding horizontal along the ceiling. This keeps the door panels higher in the building, reducing obstruction in the dock area and making better use of overhead space — useful at loading docks where height clearance matters.
Designing a new dock or reviewing what you’ve got?
A dock that works well from day one starts with the right conversations early. Talk to the Ulti team about what a dock system designed for your operation and fleet actually looks like. Explore our dock loading systems →