A cold storage building is a structural frame wrapped in a controlled envelope. The steel scope is familiar; the envelope, the vapour barrier and the interfaces with refrigeration and flooring are where projects fail.
This guide covers the points that have to be decided early, and the inputs a fabricator needs to coordinate the structure with the insulated envelope.
Where the insulated envelope sits
There are two common arrangements, and they change the steel scope completely. Either the insulated panels form the envelope and the steel frame sits outside them, or the frame sits inside and the panels are fixed to it. The choice affects connection details, thermal bridging, fire strategy and how the panels are installed.
- Envelope outside the frame: the structure is exposed to ambient conditions and needs its own coating, but thermal bridges are easier to control.
- Envelope inside the frame: the structure stays warm, but every penetration, hanger and fixing becomes a potential thermal bridge that must be detailed.
- Mixed arrangements are common in larger facilities and need a section-by-section decision, not a single rule.
The details that decide performance
- Vapour barrier continuity. The barrier belongs on the warm side and must be continuous across joints, corners, penetrations, door frames and pipe entries. Interruptions show up later as ice and corrosion.
- Thermal bridging. Every steel element crossing the envelope, including pipe supports, cable trays and door frames, needs a thermal break detail.
- Floor construction. Frozen stores usually need underfloor frost protection or a heated slab, and that arrangement has to be coordinated with column bases and anchor bolts.
- Door design. Traffic type, opening frequency and temperature difference decide whether a standard industrial door, a rapid roll door or an airlock vestibule is appropriate.
- Panel joints and fixings. Joint type, sealant, fixing spacing and corrosion protection on fixings matter as much as the panel thickness.
- Thermal movement. Long cold rooms move; the detail has to allow it without opening the envelope.
The panel specification
| Item | What to confirm |
|---|---|
| Core material | Polyurethane, PIR or mineral wool, with the fire performance requirement stated |
| Thickness | Derived from the cooling load and the temperature difference, not chosen by habit |
| Facings | Pre-painted steel grade and coating, and any food-safe or hygienic lining requirement |
| Joint type | Tongue and groove or cam-lock, with the sealing method |
| Fixings and flashings | Material, corrosion protection and who supplies them |
| Fire rating | The rating the authority having jurisdiction requires, and the test evidence to support it |
What to send with the enquiry
- Operating temperature range, and whether the store is chilled or frozen.
- Room layout, dimensions, clear height and the required clear span.
- Expected racking or storage loads, and any mezzanine or equipment loads.
- Door types, sizes, traffic pattern and any airlock requirement.
- Whether underfloor heating or frost protection is planned, and by whom.
- The refrigeration contractor's interface requirements and pipe penetration positions.
- Panel fire rating, facings and hygiene requirements.
- Whether the insulated envelope is inside or outside the steel scope.
This guide describes general practice for steel structure projects. It is not a design, and it does not replace the specification or the engineer responsible for your project.