Specifying a Narrow Aisle Warehouse: Aisle Width, Racking and Truck Choice

How to work out the aisle width you actually need, what the truck choice costs you in storage density, and when a very narrow aisle design pays for itself.

Last updated: 11 October 2026

Racking is expensive and floor space is the most expensive thing in the building. Aisle width is where the two meet, and it is usually decided by habit rather than arithmetic.

Measure between uprights, not between rack centres

This sounds obvious and is the most common error in warehouse planning. Manufacturers quote minimum aisle width between rack uprights. If you measure centre to centre you will overstate the aisle by the depth of one upright — typically 100 – 120 mm on a standard frame. On a 50-aisle building that error is several hundred square metres.

What each truck type needs

The arithmetic that decides it

Take a building 60 m deep with racking in double-deep pairs. With a 3.8 m counterbalance aisle you fit a certain number of rack faces. Change to a 2.6 m reach truck aisle and you fit meaningfully more racking in the same footprint, without touching the walls. The saving is not the truck — it is the rent you do not pay and the building you do not have to extend.

Run the comparison like this:

• Count the rack faces each truck type allows in your actual building footprint
• Multiply by pallet positions per face at your beam spacing
• Compare against the truck cost difference over five years
• Add the cost of any guide rails or racking protection the narrower truck needs

The extra costs nobody mentions

• **Guide rails** for three-way trucks — a real capital cost, and they interfere with racking access
• **Floor flatness** — VNA trucks need a flatter floor than a counterbalance truck; if your floor is out of tolerance you will be grinding it
• **Racking tolerance** — narrower aisles demand straighter racking installation
• **Operator skill** — VNA trucks take longer to learn, and a poorly trained operator in a 1.6 m aisle causes expensive damage

When it is worth it

Very narrow aisle pays when land is expensive, the building cannot be extended, and throughput is measured in pallet positions rather than movements per hour. If your constraint is speed rather than space, keep the wider aisle and buy a faster truck.

Frequently asked questions