With all the permitting delays and costs associated with new self-storage construction, many owners and developers are looking toward conversion as an alternative. Vacant, partially vacant or functionally obsolete properties exist in all markets. Some will lend themselves to self-storage, others will not. Like new construction, conversions often have their own set of challenges, but they offer advantages, too:
- Many are in fully developed areas, practically eliminating new local competition.
- Core retail demographics or traffic counts may still exist in the area even though the “A” retailers have moved to newer locations.
- The inclusion of self-storage may make a formally unfeasible single-use project work.
Do the Numbers Work?
To determine if a site is appropriate for a self-storage conversion, there are many facets to consider. First, does the site have enough square footage to make the numbers work? Can the building’s rentable area be expanded via a mezzanine system or additional floor? Some locations may not have enough square footage to make the project feasible; but in other cases, buildings will have an interior height of 18-plus feet, allowing for the installation of a mezzanine.
Unlike point-load, rigid multi-story framing systems, a self-storage framing system allows the load to be spread throughout the existing slab on 5- and 10-foot centers. It also allows the support design to follow the unit mix of the floor below. As a result, a mezzanine can be installed on many existing slabs that have a thickness of only 4 inches between footings. A thicker slab allows for even more options, such as a third floor, second-floor concrete deck vs. plywood, etc.
Regardless, upper floors will need to be designed to the standard of 125 PSF (pounds per square foot) dead load. Should you not have adequate height for a full second story, there are other options. For instance, Storage On Terminal in Vancouver, British Columbia, Canada, effectively expanded upward by offering larger than normal locker sizes. A rolling staircase allows access to the upper units, and net-square-footage requirements were met.
Assuming you have the necessary height, there are other considerations, including:
- Sprinkler/fire system additions or new installation (fire safety)
- Existing HVAC systems vs. what is needed
- Elevators or lifts
- Emergency stairways
- Parking requirement changes
- Operational layout/logistics
Even if the existing building has a sprinkler system, it will now only address the upper floor. Additional service will likely be required for the lower level. Also, check with the local fire marshal for the adequacy of the existing head spacing and water supply.
Everett Downtown Storage in Everett, Wash., before conversion (left) and after (right).
Elevators can be tricky in a conversion. Installing one is a personal decision, but they generally facilitate the ability to rent upper units. While other types of lifts can be used, elevators are the most convenient and user-friendly. The issue lies with construction. Will it be possible to dig an elevator pit and move an elevator through the roof to a penthouse constructed above it? What type of construction should the elevator shaft be? If concrete is to be used, you’ll need a method for getting it inside the building.