Roof coatings are often used to extend the life of an existing roof or can be used to change roof color. This not only upgrades the aesthetics, it can greatly improve the interior comfort for non-conditioned buildings. Choose the coating color wisely!
Requirements for roof insulation are outlined by building codes. New construction needs to meet the requirements of the International Energy Conservation Code or American Society of Heating, Refrigerating & Air-Conditioning Engineers (ASHRAE 90.1). It’s smart to construct an energy-efficient building from the onset.
Heating is generally more expensive than cooling on a per-unit basis. As a rule of thumb, the requirements for insulation increase the further north a building is located. The code-required insulation amount increases as one moves from climate zone one upward, with the highest insulation amounts required in zone eight.
Semi-heated buildings require less insulation. The codes recognize that where less energy is used, less insulation is needed. For heated self-storage buildings, the required amount of insulation is the same as that for habitable buildings. Insulation is a one-time cost that helps regulate energy use for the life of the building. It's one of the few building materials that have real monetary payback. A well-insulated building uses less energy and has lower annual energy costs.
Ideally, roofs should have two layers of insulation with staggered joints, and metal fasteners should not penetrate through all layers of insulation. A metal fastener through the entire layer of insulation is a thermal bridge that will reduce the insulation's effectiveness. When using multiple layers, the top layers should be adhered to the lowest layer. Properly installing insulation improves the energy efficiency of the roof system.
For an existing building, there are many ways to upgrade the insulation and increase the building's thermal value, whether or not a new roof is required:
- Adding below-deck insulation
- For buildings with exposed roof decks, spray-applied foams and cellulose insulations
- Adding insulation and a membrane on an existing structural metal-panel system
- Spraying polyurethane foam on the top of an existing roof system
Rooftop Solar Panels
There are a few options for rooftop solar-energy production. The most common is solar panels on racks that are attached to the roof or roof structure or held in place with ballast. There are also solar panels that adhere to the roof surface. Membrane roofs (single-ply, asphaltic) and metal-panel roofs (steel, aluminum) can be retrofitted with solar panels if solar is not installed at the time of construction. There are also “solar shingles” that are installed on steep-sloped roofs. These are installed in place of traditional shingles or tiles. In any case, it’s important to ensure the roof structure is capable of supporting the additional load.
For self-storage buildings with low energy use, the idea of solar energy is financially promising. A relatively small investment in solar energy can mean the elimination of electricity bills. Of course, there’s a lot to consider when determining if solar energy makes sense. Electricity costs, local and state incentives, and whether a building receives enough sunlight are important. However, single-story self-storage facilities likely have plenty of rooftop space and typically aren’t shaded by other buildings, so rooftop solar is worth considering.
Through roof color, insulation and solar energy, every roof has the opportunity to improve its energy efficiency and production, whether it’s an existing roof or part of a new construction project.
James R. Kirby is vice president of sustainability for the Center for Environmental Innovation in Roofing. For more information, visit www.roofingcenter.org . The Center’s criteria for rooftop solar energy is available at www.roofingcenter.org/special/pv .