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How to Calculate the Ideal Building Column Spacing for Warehouse Pallet Racking

Greg Conner | 13 September 2018

Anyone who has been through the process of laying out warehouse pallet racking knows all too well the frustrations of trying to accommodate building columns. It’s like putting together a jigsaw puzzle without being able to look at the picture on the box. No matter how you tweak your layout drawing, it seems impossible to avoid columns falling in the middle of a drive aisle or in the racking itself. Is there an ideal building column spacing that would avoid this frustrating process and maximize the number of storage locations within a building?

Let’s start with a few definitions.

Building Columns – vertical members which support the facility ceiling.  They come in variety of sizes and designs.

Uprights – vertical supports in a pallet racking system. To build a pallet racking structure, two upright frames are needed on each side to support the horizontal beams.

Beams – horizontal weight-bearing supports in a pallet racking system that connect the upright frames to each other.

Flue Space – spaces between back to back rows of pallet racking.  These back-to-back rows are connected using row spacers.  12” is the most common row spacer length to allow for slight overhang of the pallets in the back as well as allow for fire suppression if needed within the racks.  This flue space also allows for typical building columns (10” x 10”) to be buried within the racking without losing any pallet storage locations.

What do you do with building columns?

Building columns are generally spaced 40 or 50 feet apart by architects and structural engineers, due to standard steel mill member lengths. However, if you can design the building around the intended use and equipment inside, you can modify these lengths and truly get the best use of the space investment.

To optimize your pallet rack layout, there are really only two things you can do to avoid building columns falling outside of the racking and within fork truck drive aisles:

  • Position racking so that building columns land in the flue spaces of the pallet racking.
  • Position racking so that building columns land within the racking itself.

Ideally, we want to position pallet racking so building columns fall within flue spaces to avoid losing storage locations.  Keeping with this strategy, below are the ideal building column spacings for a few different single-deep pallet racking designs.  For the below exercise, we also assumed 12” x 12” building columns and 48” deep pallets (therefore no pallet overhang).

Let’s look at a typical 40-ft. building column spacing for single-deep pallet racking.


Using 48” single-deep pallet racks and 12” flue spacing, we get 11’-0” aisles.

Traditional “Wide Aisle” – If wider aisles are required for faster loading and unloading, a 156” aisle width will increase the building column spacing to 44’-0”.


Narrow Aisle – a 120” narrow aisle width will save some square footage and require only a 38’-0” building column spacing.


Very Narrow Aisle (VNA) – with proper equipment, a 60” very narrow aisle width will allow you to add an additional set of racks at a building column spacing of only 42’-0”.


Therefore, using the following formula will help determine the best building column spacing for your preferred rack layout:

[(Rack Depth x 2) Flue Aisle] x # Bays = Column Spacing

Laying out and configuring pallet racking can be challenging, especially if you are not able to work with your general contractor to optimize the building column spacing within your new building, or if you are moving into an existing building.  Bastian Solutions has over 65 years of experience helping clients optimize their warehouse pallet racking systems, and we can make sure your pallet rack layout will maximize your storage space.

Author: Greg Conner

I joined Bastian Solutions in 2005 after graduating from Purdue University. My first role was as a project engineer before transitioning to a field application engineer. After seven years, I became regional director of Indiana, overseeing all local FAEs as well as Bastian Solutions’ e-commerce business. In 2016, I was promoted to Vice President, Eastern U.S. where I oversaw sales and operations for all Eastern U.S. offices. In 2019, I was promoted to Vice President of Global Sales, now overseeing international operations and global marketing.


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