Floor Loading 101:

How to Plan for High-Density Mobile Storage System Installations

We’ve worked with architects and their teams on countless new and existing construction projects for a variety of applications—and we know there are plenty of factors for an architect to consider when planning for use of a high-density mobile storage system. We’ve highlighted a few of them these factors—for even more insight, we’d encourage you to download our Floor Loading Considerations Brochure.

By working with Spacesaver at the beginning stages of a project, we can help you conserve space as well as contribute to a significant cost savings. In being involved in the initial planning stages of the Main Library at the University of Illinois at Urbana-Champaign, the architect was able to decrease the building from 162,000 sq. ft to 91,000 sq. ft—enough to house the Library’s five million volumes and still plan for two million more.

By working with Spacesaver at the beginning stages of a project, we can help you conserve space as well as contribute to a significant cost savings. At the Main Library at the University of Illinois at Urbana-Champaign, the architect was able to fit 55 miles of shelving in 91,000 sq. ft—enough to house the 7 million volumes—instead of the original building plan, which would have made the building 78% bigger.

Need More Information?

Our Floor Loading Considerations Brochure takes an in-depth look at all of these aspects and more.

Brochure: Floor Loading Considerations | High-Density Mobile Storage

20-page Floor Loading Considerations brochure.

Most Architects and Structural Engineers are aware of Spacesaver high-density mobile storage systems. Spacesaver systems are universally recognized by all sectors of users desiring the advantages of functional utility, higher storage density, cost savings and space conservation.

Spacesaver high-density mobile storage systems offer Planners a broad selection of system configurations in standard sizes, while Spacesaver’s unique flexibility allows customization for specific applications. Spacesaver can provide choices of standardized systems and data to accommodate special conditions for existing buildings and new construction.

For all existing buildings, Spacesaver recommends that a Structural Engineer be commissioned to analyze the building's structural system and ensure it can safely support code-imposed gravity loads and, if required, seismic loads. A Structural Engineer can analyze existing structures and, if necessary, provide details on structural retrofitting. For new construction, a Structural Engineer can help select efficient structural framing details for supporting Spacesaver high-density mobile storage systems. For a recommendation of an independent Structural Engineer, contact your Spacesaver Area Contractor.

This guidebook has been prepared as an introduction to floor loading, when considering Spacesaver high-density mobile storage systems. Spacesaver Engineering Staff and Spacesaver Area Contractors will be pleased to discuss any questions you might have on floor loading or structural retrofitting.

The High-Density Concept & Carriage

Spacesaver’s high-density mobile systems maximize square-foot capacity for storage by providing movable storage shelves and aisles instead of fixed shelves and aisles. The versatile Spacesaver carriage, with its welded “uniframe” construction is designed to provide exceptional rigidity and results in minimal distortion and keeps carriage members structurally square and true under heavy loads.

Floor Load Considerations

The magnitude of a floor-load capacity required will be contingent on what’s being stored. For instance, typical floor requirements for paper files or books will be 125-200 psf (pounds per square foot), while museum applications may require 275-300 psf depending on the number of shelf tiers and type of floor system.

Rail Flexibility & Placement

The heaviest floor loads can be distributed through the flexibility of Spacesaver’s rail layout, and there are countless options for distributing these loads, simply by adjusting rail placement and spacing.


Footprint & Distribution

For a high-density mobile storage system, the Impact Area Footprint is the combined area of the storage system plus aisles. Loads from the shelves of the system are transferred to the carriages, which are transferred to the wheels, then the rails, then the structure of the building. Keep in mind that the aisles are subjected to pedestrian loads (15 psf minimum), which must be considered in conjunction with the storage system loads. In terms of rail loads, Spacesaver high-density mobile storage systems are planned with approximately equal rail loads—however, it’s also possible to develop unequal rail loading if conditions are more advantageous.

Orientation & Relocation

When evaluating floor load imposed by Spacesaver systems, initial layouts may yield conditions that don’t meet your specific criteria. However, Spacesaver’s rail size selections offer a unique ability to be reoriented over load bearing points—so satisfactory loading can be accomplished. Same with relocating a system of a certain weight to a bay’s allowable load capacity—systems can be repositioned over an adjacent bay and an additional rail can be attached so the weight can be distributed evenly.

Post Construction Modifications

There are several types of structural modifications, supplements, and suspended systems that can be utilized to reinforce the beams and joists that support a high-density mobile storage system. Click here to access drawings of some of the many modifications we’ve seen in the field.

Post Construction Modifications

Structural & Seismic Considerations

All framed floor systems are subjected to deflection when load is applied to the floor system, and the amount of deflection is proportional to the applied load. Buildings with large bays can have enough deflection, which could cause a high-density mobile storage system to drift. Spacesaver has developed a patented positioning brake, which will present a system from drifting. In addition, Spacesaver has also developed patented anti-tip systems that meet all code requirements for buildings in areas that are prone to seismic activity.

Rail Placement