For most buildings, roofing is straightforward—keep the building’s interior safe from rain, wind, and the elements. For cold storage facilities, the right roofing can make all the difference. The roof likely doesn’t factor heavily in one’s mind when considering a refrigerated building, but it serves an important function in insulation and preventing moisture build-up. Here are some pointers to keep in mind about cold storage roofing, both during the design process and after building completion.
The Value of Single-Ply Roofing
The roof’s composition depends on the expected use conditions for the building. For cold storage, maintaining the refrigerated environment inside and preventing ice buildup are paramount. Cold storage roofing, therefore, needs to be well-insulated, energy-efficient, and impermeable to water vapor. Single-ply roofing systems fulfill all of these, composed of a single membrane overlaid on the roof substrate and insulation. Thermoplastic polyolefin (TPO) is a common choice since it’s sturdy, economic, and reflects sunlight well to reduce heat and increase energy efficiency. Hot air welding makes for airtight seams, and the material itself blocks moisture.
Built-up roof (BUR) systems, the more traditional choice compared to single-ply, involves multiple layers of tar, asphalt, and gravel. Multiple layers make water less likely to penetrate through the entire system, but this makes BUR systems prone to water pooling and blistering, reducing the roof’s integrity. BUR systems also innately have great insulation, but do not strongly reflect sunlight as TPO single-ply does.
Complete the Thermal Envelope
The ‘thermal envelope’ of a building refers to all structural components of the building, both exterior and interior, that mitigate heat transfer between the building’s interior and its immediate environment. Making sure that the cold storage’s thermal envelope is continuous and airtight is critical in maintaining a refrigerated environment. This means that the roofing must integrate properly with the rest of the building, the walls of which are typically composed of insulated metal panels (IMPs).
Vapor seals should be installed at the edges of the roof where it meets with the walls, in the form of butyl sealant strips and closed-cell spray foam, as these are where air leaks are most likely. Redundancy is key; if any individual seal fails, you want there to be more seals still to maintain the building’s thermal envelope. Additionally, multiple staggered layers of seals reduce thermal bridging—discontinuities in insulation that permit heat or air to pass through. The staggered layers strongly reduce the likelihood of gaps lining up to allow a leak.
Signs of Vapor Leaks
Of course, no roofing works perfectly forever. Regular maintenance allows you to catch roofing issues earlier on and address them before too much damage is done to refrigerated products. It’s possible, though, to miss a roofing leak when inspecting the roof initially.
Moisture inside the cold storage facility leads to ice and frost buildup, as water vapor condenses in the colder air and then freezes. This is most easily noticed in and around freezers since they’re likely to be the coldest parts of the building. Condensation and icing can also be found around leaks, where the temperature drops off abruptly.
No Room for Error
The standards for cold storage roofing are well above those for other commercial and residential buildings, because a failure to maintain the interior environment endangers stored products, and potentially workers as well. Robust, energy-efficient roofing is more significant, and insulation is employed more heavily.
Crucially, a high-quality installation is just as necessary as high-quality roofing systems. Faults introduced in installation can jeopardize your facility. Your best bet is to find a roofing team with experience in installing cold storage roofing, as they’re more certain to have the right skills and know what to look for. Benton Roofing has served the Southeastern US for decades in roofing installation and repair, backed by comprehensive safety practices and industry-leading warranties and recognized as a top contractor in the field. Contact us today on our site or by phone at (888) 622-1622 to learn more and request a free quote.