8 Sustainable Roofing Strategies
Strategy No. 1: Perform routine roof maintenance and prompt repairs.
Without ongoing routine maintenance, premature roof failure is inevitable. The fewer years that a roofing system lasts, the more landfill waste is generated. A no-maintenance, constant reroofing cycle is neither cost-effective nor environmentally friendly.
A proactive approach to roof maintenance retains the efficiency of insulation by keeping it dry, which results in lower utility bills and reduced energy consumption. Routine inspections performed by roofing professionals provide you with the knowledge to address small repairs before they become big problems. The sooner that damage, defects, and wear are detected, the greater the chances that, with repairs, they won’t reduce the life of the roofing system.
Strategy No. 2: Install daylighting skylights.
Lighting is the second largest consumer of electricity in commercial facilities behind the HVAC system. Daylighting skylights can be added to the roof to reduce the amount of artificial light required inside the building. Qualified professionals can provide you with a plan that includes estimated annual energy savings in kilowatt hours (kWh) per year, as well as a prediction of annual savings based on your utility rates. Distribution centers, warehouses, and other large, one-story facilities with lots of overhead lighting are the most ideal candidates for daylighting skylights.
Strategy No. 3: Install (and clean) solar panels on the roof.
The installation of solar panels has become a viable solution to rising energy costs. This type of renewable energy project gives you the opportunity to hedge against future electricity increases or buy electricity at a discounted rate. It also reduces the facility’s carbon footprint.
Once solar panels are installed, it’s important to keep them clean. A build-up of environmental debris on the surface of solar panels dramatically reduces their energy output. The National Renewable Energy Laboratory (NREL), a Golden, CO-based federal research laboratory for the U.S. Department of Energy, reports losses as high as 25 percent in some areas.
Strategy No. 4: Put a coating (or new roof) over the existing one.
Ultraviolet and heat exposure cause chemical degradation of the roof membrane. Likewise, water accelerates deterioration. Coating metal roofs, single-ply systems, modified bitumen, built-up asphalt roofing, and spray polyurethane foam installations can slow this process by providing an extra layer of protection to the surface of the roof. Extending the life of the roof through the application of a roof coating means less frequent tear off and disposal.
Installing a new roof system over the existing one (aka recovering the roof) also has environmental benefits. It too results in less landfill waste and because the old roof assembly probably still has some R-value, it may improve the energy efficiency of your facility. Additionally, less new insulation material needs to be manufactured.
Strategy No. 5: Install a reflective roof membrane (or coating).
A reflective roof reduces your facility’s energy consumption. According to the Cool Roof Ratings Council (CRRRC), it works by reflecting and emitting the sun’s heat back into the sky, instead of transferring it into the building. This means air-conditioning equipment doesn’t have to work as hard to keep the building cool and when it runs less, the electrical bill is smaller and power plant emissions are decreased right along with the building’s carbon footprint. According to the CRRC, you can expect savings in the range of 10 to 30 percent for cooling energy and extended service life of air-conditioning equipment.
If you’re not in the market for a new roof, consider applying a white reflective roof coating. According to the White Roof Project, white coating reflects up to 90 percent of sunlight, compared to traditional black roofs that reflect only 20 percent. Have your roofing contractor check to see if the local utility company offers rebates or if the project is eligible for any government-sponsored energy rebate programs.
(It’s important to mention, though, that reflective roofs may increase heating energy demand in winter for geographies that experience cold winters. Do your research first!)
Strategy No. 6: Recycle your old roof.
According to the National Roofing Contractors Association (NRCA), more than 8 million tons of roofing tear-off waste is dumped into U.S. landfills each year. While not all roofing materials can be recycled (e.g. built-up roofs and some types of insulation), most are prime candidates for recycling, repurposing, or reuse. Beyond just demolition waste, a significant portion of the packaging for new materials brought to the site (i.e. pallets, plastic wraps, pails, and cardboard) can also be recycled. An experienced contractor can evaluate materials, estimate quantities for reclamation, and source organizations to recycle, reuse, or salvaged materials such as metal, roofing membrane, insulation, concrete, and stone ballast. Every project has some percentage that can be diverted from the landfill.
Strategy 7: Right size your roof insulation.
If your insulation isn’t performing as intended, heat is escaping in winter and entering in summer, making HVAC systems work harder to compensate. Insulation is widely accepted as the best method to capture roof-related energy savings.
When embarking on a new roofing project, it’s critical to obtain an estimate of annual energy usage costs related to insulation levels of various roof systems. The NRCA’s EnergyWise Roofing Calculator can help you evaluate virtual roof assemblies for thermal efficiency and estimate the heating and cooling cost reductions resulting from each option.
Once the roof system is installed, keep people off the roof to prevent foot traffic from compressing insulation. Another way to preserve the thermal efficiency of insulation is to fix leaks promptly to avoid wet insulation.
Strategy No. 8: Specify how your new roof system is installed.
It’s not enough to specify energy efficient roofing materials; as much attention needs to be paid to how they are installed. For example, some contractors will reach an R-value of 20 by specifying a single layer of 3-inch isocyanurate, but two layers of staggered 1.5-inch isocyanurate eliminates the thermal short.
It’s important to reduce thermal discontinuities. Insulation application strategies can greatly reduce gaps and voids and increase energy efficiency. Ask your roofing contractor about whether they’ll be using staggered joints with multiple layers of insulation or dimensionally stable products. Other approaches that eliminate thermal bridging include:
• A ballasted system.
• A mechanically fastened bottom layer and fully adhered remaining layers.
• Non-thermal bridging fasteners.
• Spray polyurethane foam.
Contact D. C. Taylor Co. at 319.731.4118 to learn more about our sustainable roofing strategies.