Dock-High vs Grade-Level Loading

A dock-high door is raised above the truck court. A lender's guide to industrial property puts these doors at typically 48 to 52 inches above the court, with common dimensions of 8 feet wide by 9 feet high, while noting there is no standard size. A trailer backs up to the door, and a forklift or pallet jack moves freight across at floor level.

A grade-level door, also called a drive-in door, sits at ground level. Vans, box trucks and forklifts can go straight through it, with no change in height. The same guide says these doors are generally significantly larger than dock doors.

A few variations come up on tours. A ramp door is a dock-high door converted to drive-in use with a ramp. A half-dock or semi-dock door sits lower for smaller trucks. A truck well is a sloped area that brings a truck down to the loading platform, which the guide says is relatively uncommon in newer buildings.

Start with a list of what actually arrives and leaves, over a typical week and your busiest one.

• Full trailers. Dock-high doors let a forklift move loads at floor level. Without docks, you may need another way to unload at grade, which could take more time and equipment.
• Box trucks. These vary in deck height. Dock doors may work with the right leveler, but a grade-level door may be simpler, particularly if the truck has a liftgate.
• Vans and pickups. Grade-level doors are the natural choice.
• Your own fleet. Grade-level doors can let vehicles park inside if the lease and fire rules allow it. Check before planning on it.
• Large equipment. Forklifts, machines and oversized items may need a tall, wide grade-level door to get in at all.
• Parcel carriers. A van at a door may be all you need.

Many operations need both, a dock for pallets and at least one grade-level door for equipment and smaller vehicles. A warehouse operator's glossary makes a similar point: high-volume cross-docking leans on several dock-high doors, while a trades or online business may need only grade-level access.

There is no universal number, so treat published ratios as a rough cross-check. NAIOP's 2012 terms and definitions list a typical ratio of docks and drive-in doors of about one per 5,000 to 15,000 square feet for a general-purpose warehouse and one per 3,000 to 10,000 for general-purpose distribution, and note that actual characteristics may vary.

A better method is to count from your own schedule: how many trucks arrive at the peak hour, how long each one takes to load or unload, and how many must be at the doors at the same time. Add room for staging behind each door. A door with nowhere to set pallets down is not much use.

The door is only part of it. A lender's guide on dock equipment notes that 18-wheeler deck heights can vary from 40 to 60 inches, and a dock leveler bridges that difference. Levelers can be mechanical, hydraulic or air-powered, built into the floor or stored vertically. The guide adds that most older properties will not have levelers. Bumpers absorb truck impacts, and seals help with weather and temperature.

Dock equipment is also a repair question. Law firm LP lists dock equipment, dock doors, levelers and overhead doors among the items a typical industrial lease makes the tenant maintain, repair and replace. Have it inspected and find out who pays.

Safety rules affect how a dock can run. Check with your safety advisor on how these apply to your operation.

• OSHA's dockboard rule requires dockboards to support the maximum intended load. It also requires run-off protection on those put into service on or after January 17, 2017, unless the employer shows no such hazard exists, and securing portable dockboards.
• OSHA's powered industrial truck rule calls for setting brakes and placing wheel chocks under the rear wheels of highway trucks when forklifts board them, and says fixed jacks may be needed to support an uncoupled semitrailer.
• OSHA also requires sufficient safe clearance for aisles and at loading docks where mechanical handling equipment is used, and its warehousing guidance recommends visual warnings near dock edges.

A dock is useless if the truck cannot reach it. The truck court is the paved area outside the doors where trucks maneuver and back in, and its depth is what you should ask about. Federal law generally requires states to allow semitrailers of at least 48 feet on the national network, with some longer lengths grandfathered, and many operations plan for 53-foot trailers. NAIOP calls the depth from the building to the end of the court its most important measure, since it affects how trucks maneuver, and it notes typical truck turning radii of 130 feet for large pure distribution facilities, 120 for medium to large ones and 110 for smaller ones. A court that also holds stored trailers will generally need more depth. Treat those as starting points. Your carriers and a site plan should confirm that the truck you use can actually make the moves.

• ✓Can our longest truck make the turn from the public street into the site?
• ✓Can it back into each door without crossing another tenant's doors or parking?
• ✓Is the court shared, and could another tenant's trucks block ours?
• ✓Are there local truck route or weight restrictions on the way in?
• ✓Can we park or drop trailers overnight, and does the lease say so?
• ✓Where do trucks wait when all the doors are full?
• ✓Is the pavement fit for loaded trailers and their landing gear?
• ✓Does a dock area have enough lighting and drainage?
• ✓Do hours or noise rules limit night deliveries?

Ask your carrier to look at the site plan before you sign. A driver will notice in a minute what a floor plan does not show.

A building's loading can sometimes be altered, but it takes structural and site work, landlord approval and possibly a permit. Adding a dock can mean cutting walls and floor and changing the pavement, and it may not be possible if the court is too shallow. Get a contractor's opinion and the landlord's position before relying on this.

Put what you are relying on in writing. LeasePilot, a lease software company, recommends that a lease set out specific measurements for dock configuration, door sizes and truck court dimensions, with diagrams attached as exhibits. Also write in your rights to use shared courts, drop trailers and receive trucks at the hours you need.

Tenant Advisory Group represents tenants and buyers. In a search, we help screen buildings against your freight profile and raise loading, yard and parking rights early in the proposal, when a landlord has a reason to agree to them.