Cold Storage Engineering Series · Part 2 of 4
Cold Room Insulation Guide: Panel Thickness, Core Materials and Vapour Control
8 min read · Updated 2026-09-11
Cold room insulation is chosen by temperature class: roughly 80–100 mm for chilled rooms, 120–150 mm for frozen rooms and 150–200 mm for blast or ULT spaces, with a continuous vapour barrier on the warm side and insulated, heated floors below freezing.
Insulation is the only part of a cold store that works every second of its life without consuming energy. Getting it right lowers plant size, running cost and moisture problems for twenty years; getting it wrong is expensive to reverse because the fix is usually behind the racking.
This guide covers the decisions buyers actually have to make: core material, thickness, vapour control, floors, and the details where heat quietly leaks in.
Key takeaways
- Thickness follows temperature difference — specify by zone, not one thickness for the whole building.
- The vapour barrier belongs on the warm side and must be continuous; moisture, not heat, destroys cold store panels.
- Frozen rooms need floor insulation plus under-floor heating or a ventilated void.
- Thermal bridges at junctions, doors and penetrations can undo a good panel specification.
Core materials in practice
Almost all industrial cold rooms are built from insulated sandwich panels: two coated steel skins around a rigid insulating core. The core choice sets thermal performance, fire behaviour and price.
| Core | Typical λ (W/m·K) | Strengths | Watch-outs |
|---|---|---|---|
| PIR (polyisocyanurate) | 0.022 – 0.024 | Best common thermal performance, good fire rating, standard for cold stores | Quality varies between manufacturers; ask for tested values |
| PUR (polyurethane) | 0.022 – 0.026 | Lower cost, widely available | Weaker fire performance than PIR; often restricted by insurers |
| Mineral wool | 0.037 – 0.042 | Excellent fire performance, often insurer-preferred | Needs ~60–70 % more thickness for the same U-value; heavier |
| EPS | 0.033 – 0.038 | Cheapest, common in light commercial rooms | Poor fire behaviour; rarely accepted for large industrial stores |
How thick should the panels be?
Thickness is driven by the temperature difference across the panel and by the ambient climate. A frozen store in a Gulf summer sees a difference above 65 K; the same store in northern Europe sees around 40 K, and the economic thickness differs accordingly.
| Room | Temperate climate | Hot / Gulf climate | Approx. U-value at the thicker figure |
|---|---|---|---|
| Ambient-controlled (+12 to +18 °C) | 60–80 mm | 80–100 mm | ≈ 0.24 W/m²K |
| Chilled (0 to +4 °C) | 80–100 mm | 100–120 mm | ≈ 0.19 W/m²K |
| Frozen (−18 to −25 °C) | 120–150 mm | 150–180 mm | ≈ 0.14 W/m²K |
| Blast / IQF (−35 to −40 °C) | 150–200 mm | 180–200 mm | ≈ 0.11 W/m²K |
| ULT (−70 to −80 °C) | 200 mm+ | 200 mm+ | ≈ 0.10 W/m²K or better |
Vapour control — the failure most buyers never see coming
Water vapour always moves from warm humid air toward cold dry air. In a frozen store that means it pushes inward through every joint, screw and cut edge, twenty-four hours a day. When it reaches a surface below dew point it condenses, and below 0 °C it freezes.
The result of a broken vapour barrier is ice inside the panel core, sagging panels, rusted skins and steadily rising energy consumption. It typically appears three to seven years after handover, and the repair means emptying the room.
- The vapour barrier sits on the warm side of the insulation, continuous across walls, ceiling and floor
- Every panel joint gets a sealed gasket and continuous mastic on the warm face
- Penetrations for pipes, cables and drains are sealed and sleeved, not foamed and forgotten
- Cut edges are re-sealed on site — an unsealed cut is an open path into the core
- Ceiling-to-wall and wall-to-floor junctions receive detailed drawings, not site improvisation
Floors below freezing
A frozen room draws heat from the ground continuously. Without insulation the ground beneath slowly freezes, expands and lifts the slab — frost heave that cracks floors and jams doors.
The standard answer is a slab build-up with 100–200 mm of high-compressive-strength insulation, a vapour barrier, and either electric or glycol under-floor heating, or a ventilated void beneath the slab.
- Specify insulation compressive strength against the actual racking leg and forklift loads
- Under-floor heating circuits must be monitored — a failed circuit is invisible until the floor lifts
- Slab flatness tolerance matters for narrow-aisle trucks; agree the standard before pouring
- Insulated floors are almost never worth value-engineering out of a frozen store
Thermal bridges and the details that leak
A building can meet its panel specification and still perform poorly if the junctions are weak. Steel fixings crossing the insulation, door frames, dock levellers, unsealed cable trays and structural columns passing through the envelope all create local paths for heat and moisture.
These points show up on a thermal camera as bright lines and, in frozen rooms, as visible frost or condensation on the warm face. A short thermographic survey at handover is a cheap way to catch them while the contractor is still on site.
What to ask suppliers for
Panel pricing looks similar between bidders until you compare what is actually specified. Ask each supplier for the same evidence and the differences become obvious.
- Core type, tested λ value and panel thickness per zone
- Fire classification and the insurer requirements it satisfies
- Steel skin thickness and coating class, especially for humid or coastal sites
- Vapour barrier and joint sealing detail drawings
- Floor build-up including insulation grade and heating method
- Warranty terms and what voids them
Frequently asked questions
How ColdMatch Group works — independent B2B procurement and sourcing platform — ColdMatch Group is an independent B2B procurement and sourcing platform for industrial refrigeration, cold storage and cold-chain projects from USD $250K+, connecting buyers with qualified third-party suppliers, EPC contractors and independent financing providers.
Turn these figures into a comparable quotation
Use the calculators to produce indicative numbers, then have them reviewed before they reach suppliers. ColdMatch is not a manufacturer, contractor, engineering firm or lender, and buyers are never connected automatically — David and the team review qualifying projects first. Serious project review generally starts from an expected total project value of USD 250,000; below that we provide guidance and calculators only.
Supplier and manufacturer listings are provided for research, transparency and discovery only. ColdMatch Group does not provide automatic buyer-supplier introductions. Every cold chain project request is reviewed manually by David / ColdMatch Group, and supplier introductions are made only after internal approval.