Cold storage facilities face unique challenges when it comes to maintaining optimal interior temperature levels. Development of cold storage roofing system design documents that both maintain interior temperatures and create an airtight roof system are important to have a high-performing cold storage roof. Uncontrolled airflow into the roofing assembly can lead to condensation within the roof and the presence of icicles or ice balls at the underside of the roof deck. Condensation and ice in the roofing assembly adds weight to the roof assembly, and wet insulation has significantly reduced R-value. A reduction in R-value means that it is more difficult for the insulation to retain interior temperatures, and cooling equipment has to work harder to maintain the interior temperature set points.
With this in mind, here are five tips on how to create a high performing cold storage roofing project:
Clearly Define Project Goals
Outline the goals for the project, such as interior temperatures, energy efficiency requirements, and methods for controlling air leakage and thermal loss. This will help guide the design phase and inform value engineering efforts related to the roof assembly selection, including specified R-values for insulation and roof assembly attachment methods.
Provide Complete Roof Assembly Design
Include a complete roof assembly design with considerations to service life, wind uplift, hail, foot traffic, and energy efficiency. The entire roof assembly including membrane selection, insulation type and R-value, coverboard selection, and roof attachment methods should take into account the design considerations. A thicker membrane, with a coverboard below it, will extend the overall service life of the roof assembly, increasing resilience to hail and foot traffic. The specified insulation type and R-value, along with the roof attachment method will impact the energy efficiency and wind uplift performance. Consideration to how the components come together to form the roof assembly are essential for achieving the project goals.
Incorporate Comprehensive Detailing
Include comprehensive details for penetrations, curbs, and roof-to-wall transitions, clearly illustrating methods for roof membrane termination with special consideration to preventing thermal bridging and air leakage. Lack of attention to detail can lead to both water leaks and air leaks, both impacting cold storage operations inside the building. Gaps in the insulation or lack of closed cell spray foam insulation at penetrations and roof-to-wall transitions creates thermal bridges allowing for escape of interior conditioned air, or infiltration of warmer exterior air. Where the warmer exterior air is able to meet with the cold interior air, condensation occurs, which often presents itself as icicles at the underside of the roof deck. Condensation that collects within the roof assembly can saturate the insulation, ultimately reducing the R-value and insulating ability of the insulation.
Specify Material Compatibility
Ensure the compatibility of all materials used within the roof system in order to achieve optimal performance and avoid potential issues during installation and throughout the life of the roof system. Specifying manufacturer tested assemblies, including proper attachment rates are crucial for ensuring that the roof system meets the wind uplift requirements. Additionally, manufacturer approved products and assemblies should be used to avoid compatibility issues, which may occur with installing dissimilar materials.
Include Installation Guidelines
Provide manufacturer's installation guidelines to ensure a successful installation of the roof system. For each component of the roof system, ensure there is proper detailing and an approved installation method that meets the design intent. Encourage communication between trades, including scheduling, particularly where the roof components interface with other building or exterior wall components. Additionally, requesting appropriate roof product and assembly submittals to confirm that the installation meets the specifications.
By focusing on the key areas of cold storage roofing design, designers can create thermally efficient and airtight roof systems that will provide a long-lasting roof for years to come. A well-designed and detailed roof plan will ensure the success of the project, promote energy efficiency, and ultimately lead to a high-performing cold storage roof.
Curious to learn more about cold storage buildings and the critical role roofing plays? Explore the GAF cold storage website, Read A Guide to Cold Storage Roof System Design, connect with the GAF Building & Roofing Sciences team, or send an email to coldstorage.assistance@gaf.com for additional information.