SpecTips: Cold Storage Design

The Cold Storage Roof Is a System, Not a Sequence of Products

In cold storage construction, the roof assembly does more than shed water. It functions as a continuous thermal and vapor control plane, managing extreme temperature differentials that drive moisture into the building envelope from the outside in warm months and from the inside in cold months. A freezer operating at -20°F beneath a summer rooftop at 140°F creates vapor pressure forces that no single product can resist alone. Yet cold storage roofs are still frequently specified as a series of independently sourced components – membrane from one manufacturer, insulation from another, vapor retarder from a third – with transitions and terminations left to field judgment.

The most vulnerable locations in any cold storage roof assembly are the points where the vapor control plane must change plane, change material, or terminate entirely:

• Roof-to-wall transitions, where the vapor retarder must connect continuously to the wall air and vapor barrier
• Penetrations for conduit, pipe, and mechanical equipment, where field-fabricated boots or generic flashings break continuity
• Expansion joints and area dividers, where differential movement between adjacent spaces at different temperatures creates stress on both the membrane and the vapor control layer beneath it
• Perimeter edges and parapets, where insulation ends and thermal bridging begins

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Carlisle SynTec Systems addresses cold storage roofing as a fully integrated assembly, from the structural deck to the finished membrane surface, with vapor control, insulation, cover board, membrane, and all transition details engineered to work together under the thermal and moisture conditions specific to refrigerated facilities.

ThermaThin™ 7: Insulation Performance Engineered for Cold Storage
Cold storage assemblies demand insulation that performs under the exact conditions present in refrigerated facilities – not just under laboratory ambient conditions. Carlisle's ThermaThin 7 polyisocyanurate insulation delivers R-7 per inch, and critically, its thermal performance improves at lower temperatures. Where conventional polyiso loses R-value as temperatures drop, ThermaThin 7 is engineered to maintain and increase effective R-value in the low temperature ranges that cold storage roofs experience continuously. This means the thermal performance specified on paper is the thermal performance delivered in the field, year after year, under the operating conditions the building was designed for. For architects specifying cold storage facilities, ThermaThin 7 eliminates the guesswork of discounting conventional polyiso R-values and provides a documentable, defensible insulation specification.

Vapor Retarder Continuity
Carlisle's vapor retarder products are selected and detailed to resist the vapor drive conditions present in cold storage environments. The vapor retarder is not an afterthought placed between insulation layers; it is a designed component with specified attachment, lap dimensions, seam treatment, and transition details at every penetration and perimeter condition. When specified as part of a Carlisle assembly, the vapor retarder is compatible with the adhesives, insulation facer materials, and membrane products above it.

Membrane Selection for Cold Storage Conditions
Not all single-ply membranes perform equally in cold storage applications. Carlisle offers PVC, TPO, and EPDM options with documented flexibility and seam performance at low temperatures. Membrane selection guidance specific to cold storage (including considerations for thermal shock, foot traffic from rooftop mechanical service, and chemical exposure from refrigerant systems) is available from Carlisle's technical team before the spec is written, not after a problem occurs.

Transition Details, Engineered and Tested
Carlisle provides complete transition details for all cold storage perimeter and penetration conditions, including roof-to-wall connections, expansion joints, equipment curbs, and pipe penetrations. These details are not generic; they are developed for the specific products in the assembly and are available in CAD and BIM formats for direct incorporation into construction documents. Field fabrication at critical transitions is minimized. Compatibility between the vapor retarder, insulation, and membrane at every transition is confirmed before installation begins.

Edge-to-Edge and Vapor Seal Warranties
When cold storage roofing components are sourced from multiple manufacturers, warranty coverage becomes fractured. Each manufacturer covers only their product. When a failure occurs at a transition — the most likely failure point — accountability is disputed and the building owner bears the cost of resolution while the investigation proceeds. Carlisle's integrated cold storage assemblies are eligible for Edge-to-Edge Warranty coverage that includes the metal, vapor retarder, insulation, cover board, membrane, and transition details as one covered system. And for the terminations and details where vapor failures most commonly originate, Carlisle's Vapor Seal Warranty provides dedicated coverage for all vapor retarder terminations (at walls, penetrations, curbs, and perimeter conditions) if Carlisle products are used throughout the assembly. Together, these warranties mean there is no uncovered seam, no disputed termination, and no accountability gap between products at the locations where cold storage assemblies are most likely to fail. One assembly. One manufacturer. Complete coverage.

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In 3-Part Specifications for cold storage roofing assemblies, include the following:

• Vapor Retarder Continuity: The vapor retarder must be specified as a manufacturer-designated component of the roof assembly, with required lap dimensions, seam treatment method, and transition details at all penetrations and perimeter conditions, under the "Products" section.
• Transition Detail Submittals: Manufacturer-prepared transition details for all roof-to-wall connections, expansion joints, and penetrations must be included in the submittal package under "Informational Submittals."
• Cold Storage Insulation Documentation: Insulation R-value documentation must reflect actual thermal performance under cold storage operating temperatures. Specify ThermaThin 7 Polyisocyanurate for documented R-7 per inch performance that improves at lower temperatures, under "Informational Submittals."
• Vapor Seal Warranty: All vapor retarder terminations at details, penetrations, and perimeter conditions must be covered under the manufacturer's Vapor Seal Warranty. Requires Carlisle products throughout the assembly, under "Warranty."
• Single-Source Assembly Warranty: The metal, vapor retarder, insulation, membrane, and all transition components must be covered under one manufacturer's Total System Warranty, under "Warranty."

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For cold storage assembly specifications, transition details, and technical support, click here.  
For more information on Carlisle’s new ThermaThin 7, click here.