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The International Energy Conservation Code (IECC) has completely changed the metal building industry over the past decade. Manufacturers have spent many years developing products to satisfy the code better. Insulated metal panels have gained an incredible amount of market share. Insulation producers have continued to develop technology around High-R fiberglass insulation systems. Some metal building manufacturers have developed erector-friendly technologies, and others have remained entirely out of the “insulation business.”
For companies to succeed in the next decade and continue to promote the advancement of metal building systems in the low-rise construction market, manufacturers and contractors must master the energy code. We must become experts on code compliance, fully understand the available components and assemblies, and perfect the efficient installation of energy-compliant building envelope systems.
Contractors need to understand the energy code. We cannot rely on manufacturers and architects to do the work for us. We need to educate ourselves.
There are three main ways to comply with the energy code:
R-value is a material’s measure or rating of its resistance to the flow of heat. The R-value Method is a way to comply with the energy code by providing the exact system in the code based on utilizing components with the specified “R-values.” For example, in New York, the prescribed R-values for a metal building roof system is “R-19 + R-11 LS,” which means there needs to be a 6″ R-19 layer of insulation and a 3.5″ R-11 layer of insulation combined with a liner style vapor barrier. The vapor barrier is installed on the underside of the purlins and supported by banding. The 6″ R-19 layer is installed in the purlin cavity, and the 3.5″ thick layer is installed over the purlins.
U-factor, or U-value, measures heat transmission through a building assembly. Unlike the R-value, the U-value is not a material rating but a calculation of various material properties working together in an assembly.
The U-factor method determines code compliance based on the U-factor of an assembly. The R-values of the individual components do not matter; what matters is the U-factor of the overall assembly. You can utilize fiberglass insulation systems, insulated panels, or a combination.
ComCheck is a system provided by the US Department of Energy (DOE) that tells users if their entire building system meets the requirements of the IECC. Utilizing ComCheck, you can combine different assemblies to create an energy-compliant building envelope. For example, you can use a roof assembly whose performance surpasses the energy performance requirements of the code and utilize a wall assembly that underperforms the code and still has an overall energy-compliant building. This method of compliance is often called the “Trade-Off” method; you can trade a more energy-efficient roof for a less energy-efficient wall system and vice versa. Even the foundation and under-slab insulation system affect determining the code compliance of the building. ComCheck provides the contractor with the most flexibility when designing an energy-code-compliant building.
Just like there are multiple ways to satisfy the energy code, multiple assemblies are available in the market.
The easiest way to comply with the energy code is to utilize insulated metal roof and wall panels. The panels provide a continuous R-value and excellent in-place U-factors. Installation is a one-part process, versus the multiple steps required to install a high-r fiberglass insulation assembly. But the panels have their drawbacks. They are expensive and require additional equipment to install. Additionally, there is a much longer lead time on insulated panels when compared to traditional single-skin panels.
Utilizing a liner-style system is the most common method of meeting the energy code using fiberglass insulation. Thermal Designs came out with its “Simple Saver” several years back, and Owen’s Corning has its “Optiliner System.” These systems utilize a vapor barrier liner, banding, and fiberglass insulation, as described above in the R-value code compliance example. In terms of material costs, these systems are the most economical. However, they require significantly more labor than a traditional single layer of insulation or even an insulated panel. The systems need you to work above and below the roof purlins, which requires additional workers and equipment. The system can also be challenging to install in inclement weather, as you are required to install an entire roof bay of vapor barrier at a time. If the vapor barrier is out and it snows, you have a real problem. If you are in a high-wind area, installing the vapor barrier and making it look pretty can be a real challenge.
Several metal building manufacturers have devised solutions to meet the code using more “erector-friendly” methods. An example would be Varco Pruden’s Thermalift system. The system utilizes fiberglass insulation and Varco Pruden’s Thermalift spacer, allowing all the insulation to be installed from the “top side” of the roof. The system uses traditional rolled insulation with the vapor barrier adhered right to the bottom layer of fiberglass. The insulation runs parallel to the roof panel, so you can roll the insulation out as you sheet versus having to insulate an entire bay of roof, as with the liner style systems outlined above. These proprietary systems are great solutions to meet the code, but erectors need to get more “reps” with these systems as they are much newer than the liner-style systems.
It is the contractor’s responsibility to understand the best, most cost-effective means of meeting the energy code. Specifiers know what the code requires but do not always know the most effective assembly to meet the code. Manufacturers want you to buy their products, so they will always point to the benefits of their systems while neglecting the downsides.
The contractors that invest the time and resources into determining the best methods of meeting the code will be the companies that succeed in the market moving forward. Having accurate data plays a key role here. Companies that self-perform metal building installations are at a particular advantage, as they should have records of the time it takes to install the various panel assemblies. They need to utilize these records to understand where the sweet spot is and what is the most cost-effective tradeoff between material costs and labor costs.
This answer can vary for different companies. A company may own a crane and a vacuum lifter for insulated panels and has perfected their installation. They may be more cost-effective utilizing insulated metal panels because their labor hours and associated costs are reduced so significantly that it outweighs the premium paid for them.
Another company that must pay for a crane rental may find that insulated panels increase labor costs compared to a fiberglass liner insulation system. They may be very comfortable installing the liner-style systems, and they can be more competitive with the lower price of the liner system material components.
The type of system utilized may differ based on the size of the building. For example, on very small buildings, the costs of insulated panels can be very high from a square foot perspective, and a liner insulation system makes the most sense. On a large wide bay building with a single roof bay that could be over 7500 square feet, a liner-style system might not be feasible, and insulated panels are required.
Meeting the energy code has become a major consideration in every building design. Rather than fight the code, we, as contractors, need to embrace the code. Those who invest in learning more about the code and the means to satisfy it will gain a major competitive advantage and position themselves as an expert in the market.