Cold store and controlled-environment structures
Cold stores combine heavy racking loads with a low-temperature environment that moves, cracks and heaves structures never designed for the cold. We engineer chilled and frozen storage buildings that stay stable and airtight at temperature, for operators across the UK.
Why do frozen store floors heave?
If a slab is held below freezing long enough, the cold reaches the moist ground below, which freezes, expands and lifts the floor. We design under-slab insulation and, where needed, an under-floor heating or ventilation system to keep the ground above freezing so it cannot heave.
Structure at low temperature
A cold store is a large insulated box held at anything from chilled to deep-frozen temperature, and the temperature drives the structural design as much as the loads. Steel and concrete contract as they cool, so a frozen store contracts measurably from the temperature it was built at, and that movement has to be allowed for in the frame, the joints and the connections rather than resisted, or the structure will crack. We design the frame and the movement joints so the building can shrink to temperature without distress.
The frame itself is usually a steel portal or braced structure carrying the roof, the insulated panel envelope and, often, high-bay racking or a rack-clad structure where the racking is part of the building. We size the members to BS EN 1993 for the roof, snow and wind loads and for the racking and services, keeping the internal columns clear for the storage layout and coordinating closely with the refrigeration and insulated panel systems that make the box work.
Floors, heave and ground freezing
The floor of a frozen store is the detail that catches out the unwary. Hold a slab below zero for long enough and the cold travels down into the ground, and if that ground contains moisture it freezes and expands, heaving the floor and cracking the structure above. We design frozen store floors with under-slab insulation and, where needed, an under-floor heating or ventilation system that keeps the ground below freezing point, so the ground does not freeze and heave.
The floor slab also carries the heaviest loads in the building. Fully loaded high-bay racking concentrates very large point loads onto small base plates, and fork-lift and reach-truck wheels add moving load, all onto a slab that is sitting on insulation. We design the slab thickness, reinforcement and joint layout for the racking and traffic loads while keeping it compatible with the insulation and heave-prevention system below, so capacity and thermal performance work together.
Envelope, airtightness and coordination
The insulated envelope is structural as well as thermal. The panels carry wind load and brace the frame, and any gap or thermal bridge lets warm, moist air in, which condenses and freezes and slowly destroys the fabric. We coordinate the frame with the panel system so fixings, penetrations and junctions stay both structurally sound and airtight, and we detail around doors, dock seals and service penetrations where the envelope is most vulnerable.
Everything in a cold store has to be coordinated, because the refrigeration, the racking, the envelope and the structure are one interdependent system. We design the structure to the Eurocodes and the relevant UK National Annex, coordinate it with the refrigeration and panel contractors, and deliver calculations and drawings that let the building be built airtight, at temperature and to load. Where an existing store is being extended or re-racked, we appraise the frame and floor before any new load or opening is added.
What we check.
The points our calculations resolve for a project like this.
- Thermal contraction of the frame allowed for at freezing temperatures
- Movement joints so the box can shrink to temperature without cracking
- Under-slab insulation and heave prevention to stop the ground freezing
- Heavy high-bay racking and truck loads on an insulated floor slab
- Insulated panel envelope acting as bracing and staying airtight
- Coordination of structure, refrigeration and racking as one system
From enquiry to sign-off.
Enquiry
Send drawings or describe the problem. We confirm the scope, the deliverables and a target timescale.
Information
We agree the survey, drawings or data we need and any site access required.
Engineering
Design, calculation or assessment to the relevant Eurocodes and UK National Annex.
Issue
A clear, defensible report or set of calculations, with assumptions and limitations stated.
Common questions
Why do frozen store floors heave?
If a slab is held below freezing long enough, the cold reaches the moist ground below, which freezes, expands and lifts the floor. We design under-slab insulation and, where needed, an under-floor heating or ventilation system to keep the ground above freezing so it cannot heave.
Does the cold affect the steel frame?
Yes. Steel and concrete contract as they cool, so a frozen store shrinks from the temperature it was built at. We allow for that movement in the frame, joints and connections so the building can reach temperature without cracking.
Can you design a rack-clad or high-bay cold store?
Yes. We design the frame and floor for the high-bay racking and truck loads, coordinate with the racking and insulated panel systems, and keep the floor compatible with the insulation and heave prevention below.
Do you work on cold stores across the UK?
Yes. We engineer chilled and frozen storage for operators across the UK, delivering calculations remotely and arranging site visits by region.
Related in commercial, industrial & agricultural structural engineering.
Tell us what you are building.
Send the drawings or describe the project. We confirm scope, deliverables and a realistic timescale.
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