Self-Storage Facility Design: Maximizing Land Use and Property Potential

By Bruce Jordan

There are many factors to consider during the development of a successful self-storage project. Market influences, local politics, zoning, development standards, topography, parcel configuration and phasing all play a role in shaping facility design. A thorough analysis and understanding of these issues will help you select the optimum design for a particular site and maximize both the land and the property’s potential. Let’s take a detailed look at these critical criteria.

Zoning and Development Standards

When I start designing a particular site, I want to have a very complete understanding of the jurisdiction’s zoning ordinance and its impact on the subject location. Having designed self-storage throughout the United States, I can tell you the effect of zoning varies greatly from one city to another.

The term “discretionary review” is often misunderstood, but it’s important to know when it applies to your property. It means a jurisdiction has the right to review and impose conditions on a proposed project design. Under this provision, city councils, planning commissions, design-review boards and zoning administrators are given the right to modify or impose conditions on a project if they believe the changes are necessary to make it compatible with a community or neighborhood. If a zoning ordinance gives the jurisdiction discretionary review over your project, you’ll likely need to pay particular attention to aesthetics, materials and local politics.

Some cites will have a limitation on floor-area ratio (FAR), the ratio of land area to building area. Other may impose a lot-coverage restriction, which is the percentage of land area covered by the building’s footprint. While FAR limitations restrict the total building area on all levels, lot-coverage restrictions only limit what intersects with the ground; upper stories aren’t regulated other than by height limitations.

Some cities exempt mechanical rooms and the thickness of the exterior walls from the FAR. Understanding this can potentially add thousands of square feet to a project. Similarly, some cities exempt a basement area. Since most jurisdictions define a basement as a floor area being more than 50 percent below grade, a lower floor with roll-up doors facing a drive aisle may be exempt from FAR limitations if the opposite side of the building’s lower level is 100 percent below grade.

Topography

While topography can present design challenges, you can sometimes use it to your advantage. For example, it can be used to gain access to two levels, where a lower drive aisle serves the first floor, an upper drive aisle serves the second floor, and both drive aisles are joined via a 10 percent sloping ramp on the narrow end of the building. We call this an over/under design. A site with eight to 12 feet of fall will allow for such a configuration.

The advantage here is in achieving much higher efficiency from eliminating elevator shafts, machine rooms and exit stairs as well as reducing internal hallways. A conventional elevator serving a two- to three-story building will have approximately 75 percent efficiency (the ratio of net to gross square feet), and a building served by a two-story ramp will have approximately 88 percent to 90 percent efficiency. The over/under configuration will have many more drive-aisle-accessible units and, hence, less need for interior hallways. Since the gross building area drives costs and net area drives income, it's easy to see that a 13 percent to 15 percent increase in efficiency can have a positive impact on a project’s bottom line.

A similar and equally efficient technique for flat sites with minimal topography is the two-story ramp concept. This usually employs a fortress design, with single-story buildings on the perimeter and a pair of two-story buildings in the center of the site. In this configuration, the outer drive aisles serve the first floors of all buildings, and a ramp aisle between the two-story buildings serves the second floors of those structures. Similar to the over/under concept, this will usually result in an efficiency upward of 90 percent. Zero elevators and more drive-aisle-accessible units increase the efficiency.

Both of these designs types work well in urban areas where land costs would limit the feasibility of a single-story project and its lower coverage.

Parcel Configuration

Every site has a particular shape and size and other parameters that must be addressed to achieve maximum use of the property. For example, a site in a completely climate-controlled market will have a different design than one in a market with minimal or no climate-controlled units. A facility with all climate-controlled units will likely include a consolidated multi-story building or multiple buildings.

While I’m a big fan of fortress-style design, it's not the best for facilities with 100 percent climate-controlled units. Conversely, it does usually offer good site coverage and efficient design, where the greatest area is at the perimeter of the project and the drive aisles are more efficient, serving buildings on both sides. The benefits of fortress design are greater building area, more drive-aisle-accessible units and perimeter security provided by the buildings. By moving the drive aisles inward, you also wind up with less asphalt.

Multi-story buildings on small sites are more influenced by internal design and efficiency, loading areas and elevator placement. More often than not, these structures are climate-controlled, and hence, you need to consolidate the building’s mass. Given a three-story, climate-controlled building on a relatively small site, you have a few options for gaining maximum efficiency.

First, the loading area (a key design element in multi-story design), doesn’t need to be internal where it would compete with the net rentable area for FAR or lot coverage. Internal vehicular circulation can take its toll on net square footage due to the need for backup space, parking spaces and driveway circulation. In this case, I would opt for an external, canopy-covered loading area, since canopies aren’t counted in FAR or lot coverage.

Internal circulation also takes larger spans to accommodate vehicles, resulting in structural steel beams straddling longer distances. This adds to costs and triggers the need to raise the second floor to accommodate moving trucks. This takes on more significance on a conversion project since the existing internal clearance may not be high enough for an internal loading area. An external, canopy-covered loading area can work just fine in such a situation. If properly designed, this option can provide an advantage over your competitors.

Finally, an option for projects in dense urban markets is the potential use of locker units above the 8-foot-high units fronting the hallways. These are accessible via rolling ladders, and while they’re usually rented for less per square foot than traditional units, they relatively cost-effective and aren’t counted in FAR or lot coverage, as they have no direct floor access.

Phasing

Phasing for a self-storage project should be carefully considered. Disruptive impact from second-phase construction includes onsite development activity, dust, dirt and a reduction in property access. I recommend preparing an overall master plan for the site, giving careful consideration to how you’ll separate the operating facility from new construction. A proper plan will minimize disruption.

For example, RV-storage spaces can be designed to provide an additional source of income during phase one while the new facility is in lease-up. They can then be phased out as demand grows for self-storage and linear buildings are extended for the more profitable second phase of the project. Once you have a management office, gate controls and a manager, the cost for RV storage can be fairly small, so if you have a site with ample acreage to accommodate a full first phase, it makes sense to consider this option.

Maximizing a site’s development potential is key to designing a fruitful project. Having a thorough understanding of a market’s zoning, development standards and other factors will give you the tools for success. I recommend looking at several design options for a site. Ruling out the less-efficient options will enable you to zero in on the optimum design to fit your particular parcel. Sometimes the options we rule out are almost as important as the ones we rule in.