By James R. Kirby
Self-storage buildings are a unique type. Many are single-story with large doors, and have sloped roofs that drain to gutters. Economical construction methods are used, with metal buildings and concrete masonry a frequent choice. Interior finishes are inexpensive or excluded, and exterior finishes include paints or coatings. This type of construction is extremely appropriate and an effective way to house people’s extra stuff.
Of course, storage facilities can consist of any building type and can be several stories tall. Existing buildings, such as warehouses, can be converted to self-storage. In addition, these buildings are not inhabited, so they already use minimal energy.
The roof is a considerable portion of a self-storage building envelope, which consists of the roof, walls and all penetrations, such as doors, windows and skylights. Many facilities include metal roofs, which is a practical choice because the metal panels also act as the roof deck. This one product serves two functions, reducing material and labor costs.
A roof's energy efficiency comes from roof color, the amount of insulation and the production of renewable energy. Rooftop energy production includes solar electricity (rooftop photovoltaic systems), solar thermal (rooftop hot-water systems) and wind energy. While the use of small-scale wind turbines is not common, solar electricity is an expanding business. Here’s an overview of how these three key roofing components—color, insulation and renewable energy—can help a self-storage facility be more energy-efficient.
Geography plays a role in the construction of self-storage buildings, certainly when it comes to roof design. The United States is divided into eight climate zones, and they’re primarily based on heating and cooling requirements. Climate zone one is the most southern and generally requires the most cooling and the least heating. Climate zone eight is the most northern and generally requires the most heating and the least cooling. There's more to it than that, but that’s the gist of climate zones.
Roof design and construction affects the energy efficiency and interior comfort level of a self-storage facility. Roof color and the amount of insulation are key factors that help regulate the interior building temperature, especially in single-story, non-conditioned buildings, which is often the case for self-storage.
For a roof with minimal insulation, a dark color will absorb the sun’s energy, transferring the heat into the building. This is good during a Minnesota winter, but not very desirable for an Arizona summer. In contrast, a white- or light-colored roof will reflect the sun’s energy and less heat will be transferred into the building.
Roof color on minimally insulated buildings is a balancing act. In much of the country, it’s neither “always hot” or “always cold,” so perhaps the most practical color for a roof on a self-storage building is a medium color, like a gray or green. The roofing industry has many options that fit into this color scheme.