Shop industrial space on clear height, not square feet

The most common brief we receive from a growing distributor is a square footage number. It is almost always the wrong starting point, because square footage is an output of the racking decision, not an input to it.

Start with pallet positions. How many do you hold at peak, not at average? What is your pallet footprint and your rack configuration? Once you know you need, say, 14,800 positions at five high in a narrow aisle system, the clear height requirement is fixed at 32 feet, and every building under that is off the list no matter how large it is.

What height buys you

Clear height is measured to the lowest structural obstruction or the sprinkler deflector, whichever is lower, at the first column line. Not at the ridge. Ask for it at the first column and ask what the obstruction is.

• 24 to 28 feet: four high selective racking of standard pallets. Adequate for most light manufacturing and for distributors with low pallet counts.
• 32 feet: five high selective. This is the current standard for new Twin Cities bulk distribution product and the height most regional distributors should be targeting.
• 36 feet and above: five to six high with narrow aisle or very narrow aisle equipment. Requires a slab poured to a much tighter flatness tolerance.

The specifications that travel with it

Height alone is not enough. A 32 foot building with a standard sprinkler system may still need in-rack heads, which costs money and eats volume. ESFR sprinklers let most users rack to clearance without additional fire protection work, and that is worth asking about before the tour, not during it.

The slab matters just as much. Six to eight inches at 400 to 600 pounds per square foot is the modern distribution standard. Older manufacturing slabs vary, and flatness tolerance is the specification that quietly decides whether a turret truck at 35 feet of lift will work at all.

Then column spacing. A 50 by 52 foot grid gives you clean rack runs. A 40 foot grid in an older building will cost you aisles and positions no matter how tall it is.

A worked example

A client came to us looking for 90,000 square feet because that was 30 percent more than their existing 70,000. Their real requirement was 14,800 pallet positions. At 28 feet clear in a four high configuration, that needed roughly 118,000 square feet. At 32 feet in a five high configuration, it needed about 94,000.

The taller building was 24,000 square feet smaller and, at the rates then available, about 118,000 dollars a year cheaper in gross occupancy cost. It also gave them room to grow without moving again. Square footage would never have got them there.

Figures in this article are illustrative samples for a demonstration website.