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How to choose the right sandwich panel thickness
Last reviewed:
Short answer
Thickness follows use: 40 – 50 mm for non-air-conditioned stores and hangars, 50 – 75 mm for workshops and offices, 75 – 100 mm PU for air-conditioned buildings, 100 mm for chillers and 120 – 150 mm for freezers. Thicker panels lose less heat and can usually span further between purlins.
Thickness by use
| Use | Typical thickness | Suggested core |
|---|---|---|
| Non-AC stores and hangars | 40 – 50 mm | EPS |
| Workshops and plants | 50 – 75 mm | EPS or PU |
| Offices and AC buildings | 75 – 100 mm | PU |
| Chillers (0 to +5 °C) | 100 mm | PU |
| Freezers (−18 °C and below) | 120 – 150 mm | PU |
| Sites requiring fire resistance | 50 – 100 mm | Rock wool |
Core type can matter more than thickness
Polyurethane insulates about one and a half times better than EPS at the same thickness, so a 50 mm PU panel performs close to a 75 – 80 mm EPS panel. Rock wool insulates less and is heavier, but it does not burn.
Thickness and purlin spacing
A thicker panel is stiffer and can span further between purlins. Do not pick thickness on insulation alone — check the manufacturer's load table against the purlin spacing in your design.
What to put in your quotation request
- Core type and thickness (e.g. PU 50 mm)
- Roof or wall, and skin thickness per face if specified
- Required colour
- Area in m² or number and length of panels
- Delivery location and whether you need accessories (screws, ridge caps, flashings)
FAQ
Is 40 mm enough for an office roof?
Usually not if it is air-conditioned — 75 mm PU or more noticeably reduces cooling load.
General guidance — not an offer or commitment by BUILDORA.