Self-storage facilities of three or more floors are becoming increasingly common in heavily populated areas where land is scarce and expensive. Economics and the law of supply and demand necessitate multistory building, often with one or two basement levels. But designing and building a project to achieve this “extreme” level of land utilization requires a great deal of expertise and patience, as there is little room for error on small parcels.
After a developer has worked with his real estate consultant and market analyst to find the right parcel in the right location at the right price (with good market conditions), the architect and design team are brought into the picture. The next step of the development process begins with a few key questions:
1. Are the government land-use approvals possible?
2. Will the development code or zoning ordinance allow intense use of the land?
3. Can the building and fire-code requirements for construction, safety exiting and emergency access be met?
4. Can a functional design with the necessary amount of building area be achieved?
Although these critical questions are closely related, a closer look reveals a reliable methodology that can be used to achieve success in site planning and building design.
The land-use approval process is different in each jurisdiction and is based on whether a project is acceptable to a community from the perspective of land use. The process can be highly political and is a complete subject matter onto itself. In this article, I’ll focus on the nonpolitical issues that guide the physical form and function of multistory development, with the assumption that land-use approvals are obtained or obtainable.
Every jurisdiction has restrictions that guide property development. These guidelines can be in the form of a zoning ordinance or general development code. The purpose of these rules is to give the city or county some sort of control over property development, hopefully resulting in an orderly or consistent appearance in the community’s physical environment. The specifics of these codes dictate a building’s size, mass and form. They primarily address floor-area ratio, lot coverage, building height, building setbacks and parking requirements.
Floor-Area Ratio.The maximum allowable floor-area ratio (FAR) is the most important factor determining what can be built on a site. FAR is the relationship between a building’s total square footage, including all levels, divided by the size of the parcel. For example, a 40,000-square-foot building on an 80,000-square-foot lot has a FAR of 0.5. In most urban areas, a typical limit may be 1.0 to 1.5, possibly more. A 1.5 FAR would allow a 65,340 square-foot-building on a 1-acre lot or a 130,680-square-foot building on a 2- acre lot, both of which provide an acceptable level of site utilization.
Although some jurisdictions don’t limit the FAR, most do. FAR restrictions are generally rooted in a community’s general plan. Because they’re intended to control the density of the built environment, it’s often difficult to obtain a FAR that exceeds stated allowable limits.
Lot Coverage.Similarly, most jurisdictions limit how much of a site can be covered by a building. This is known as maximum lot coverage, the relationship between the building “footprint” and the size of the site. The footprint is the first-floor area of a building in square feet. Lot coverage does not limit FAR, meaning the firstfloor footprint can vertically extend through one or more stories of construction.
The most common lot-coverage restriction falls in the range of 50 percent to 75 percent, allowing fairly intense site utilization. For example, an 80,000 square foot parcel with a 50 percent maximum lot coverage allows a building with a 40,000-square-foot footprint.
Building Height.Another restriction on development is maximum building height, how high the building can extend above ground. Urban areas generally allow tall buildings, so this component is not much of an obstacle in those markets. Typical building height might be 50 to 75 feet where restricted, and much higher where high-rise development is common. There are several examples of 10-story self-storage buildings in downtown city areas.
Building Setbacks.Setbacks limit how close a building can be placed to a parcel’s property lines. Specific setbacks are designated for the front yard, which faces the street, and the side and rear yards, which make up the parcel’s other sides. Urban areas generally have nominal requirements, especially where large buildings are close together and to the street. Nevertheless, this restriction must be carefully assessed, as even setbacks of just 5 or 10 feet can use up a large portion of a small parcel.
Parking Requirements.Most government agencies in urban communities understand the nature of the self-storage business and that it requires minimal parking. However, some development codes still group self-storage with more intense commercial or industrial land uses. This results in parking requirements that greatly exceed the need, as well as an inefficient site design and smaller building footprints. The developer or architect must have a firm grasp of the actual parking and loading requirements of self-storage. A parking variance may be necessary to bring the requirement down to a reasonable level.
Building and Fire-Code Requirements
In addition to meeting development-code requirements, a building must satisfy the demands of local building and fire codes. Although most of these are technical in nature and beyond the scope of this article, it’s helpful to understand their intent.
Building Areas.Building areas are limited based on types of construction and distance to property lines. Generally speaking, the more fire-resistant a building is, the larger it can be. Similarly, the more room there is on a site, the more relaxed the rules become. Large buildings may require fire-separation walls, which compartmentalize a building for the purpose of slowing or stopping the spread of fire.
Fire Exits.The building code tightly monitors requirements for the safe exiting of tenants during a fire. There must be stairs to safely guide occupants to the ground in an emergency. A minimum of two sets of stairs is required per floor, spaced reasonably far apart. Elevators cannot be used as fire exits.
Fire Sprinklers.Sprinkler systems are universally required on large multistory buildings, along with extensive smoke-detection and fire-alarm systems.
Emergency Site Access.Fire departments require access to a site—or an adjacent site—for fire-fighting purposes. Fire lanes, generally a minimum of 20 feet wide, are required to allow truck access, as well as the appropriate turning radiuses. Taller buildings may need wider lanes to accommodate ladder angles.
Space and Operational Requirements
After meeting the requirements of development, building and fire codes, the design team is ready to begin site planning. The next challenges are site and building access and the overall floor plan.
Site Access.The site’s driveway locations must accommodate large vans and trucks typically used by self-storage tenants. Access should be visibly clear for all drivers. New customers should be able to quickly and easily locate the parking area and office without disturbing other tenants who may be loading or unloading goods. Some accommodation should be made for parking large vehicles outside the gate-secured area. Established tenants should be able to enter the facility without delay.
Building Access.Elevator placement is the most important component of building access in a multistory project. Unlike their drive-up counterparts, multistory projects lack the luxury of widely dispersed units. To keep tenants from getting in one another’s way, elevator areas should be easily accessible. Larger projects definitely require more than one elevator to eliminate crowded conditions and reduce the travel distance to all units.
Building access will also involve security. Some multistory facilities may not have gates due to lack of space. In those cases, the line of security is the building itself, so special consideration must be given to code access on first-floor hallways and elevators.
Floor-Plan Design.Once site and building access are addressed, the building has taken its final form. An efficient floor-by-floor design should follow, meeting the unit-mix target as efficiently as possible. General floor-plan considerations include:
- Elevator and stair placement.
- Hallway layout (to facilitate access to all units).
- Placement of large units (close to elevators) and small units (at the extremities).
- Office placement (to allow security monitoring and tenant assistance).
- Office design (to convey security and facilitate financial transactions).
- Placement of fire-rated components.
While the basics of intense site utilization may be challenging, there is a method for achieving success. Self-storage developers have been rewarded with great returns from their multistory projects. This makes the challenge worthwhile.
Ariel Valli is the president of Aliso Viejo, Calif.- based Valli Architectural Group, which provides architectural-design services for self-storage and land-use entitlements. The company also offers construction documents for self-storage development in the Western United States. For more information, call 949.349.1777; e-mail firstname.lastname@example.org.