By Jared Donnamiller, PE
Partner, AKF Group
Multistory warehouses may be the future of warehousing in the United States’ dense urban markets. Global e-commerce sales continue to climb as a share of overall retail sales. E-commerce retail sales are expected to top $1 trillion in 2022, according to the U.S. Department of Commerce, as e-commerce continues to penetrate the retail market. Businesses are working to increase parcel volume to match growing demand and expedite deliveries to satisfy the same-day or next-day delivery expected by consumers. The ever-growing demand and need for prompt fulfilment is forcing businesses and developers to react to the market with more warehouse space that is closer to the consumer. When development footprint in the middle of major U.S. cities is high in price and in low supply, you must build up, not out — this has been the answer in the commercial and residential markets for decades.
The concept of a multistory warehouse is not a new one, globally. High land costs and densely populated urban centers across Asia-Pacific created the demand for multistory warehouses. Some of the multistory warehouse stock has been in operation for more than 25 years with developments as tall as 24-stories. Multistory warehouses in the U.S. have previously been considered speculative construction given the lack of tenant demand. Historically low vacancy rates and growing demand are now pushing developers to explore multistory sites in densely populated urban areas, forcing U.S.-based architectural and engineering design firms to think differently about these innovative and complex developments.
A single-story warehouse in the middle of an industrial park requires a relatively simple design regarding Mechanical, Electrical, Plumbing and Fire Protection systems. Roof access allows for gas or electric fired rooftop AC units with direct penetrations into the space and limited ductwork distribution. Ground space is available on the sites for exterior pump houses and electrical service closets. Multiple stories present challenges with system selection, vertical distribution and the potential for high-rise design requirements.
A warehouse with three or more stories can be surrounded by integrated ramping to get delivery vans and in some cases, 53-foot trucks, up to the upper floor truck courts. This can leave limited façade space for HVAC intake or exhaust, necessitating mechanical systems to be centrally located on the roof level with vertical distribution through the floors. Vertical piping and ductwork must then be coordinated to limit the loss of usable floor area. This same verticality extends to fire protection systems, electrical distribution and plumbing stacks.
Floor-to-floor heights is a favorite topic of discussion in the industrial market with heights ranging from 18 to 40-feet clear. It only takes a few floors to have the highest occupied floor above 75-feet. High-rise design introduces requirements and challenges with stair pressurization, stack effect, complex fire protection systems, and generator requirements. Multiple floors on one lot also increases the typical power density of the site. The introduction of EV charging for commercial vans further impacts the power requirements and, in some cases, demands more than what is available from the utility in some industrial zoned neighborhoods.
It is unclear if multistory warehouses are the way of the future in the urban markets in the U.S., but elegant design solutions exist that support the concept. Developers, architects and engineers continue to advance multistory design to support the future needs of owners and operators in dense urban markets. Last-mile logistics related to same-day and next-day deliveries will continue to drive the demand for warehouses near consumers; how tall they will go has yet to be seen.
