In short
A sandwich panel is two steel skins with a PIR, PUR, EPS or mineral wool core. Thicker panels insulate better; the effective width is typically 1000 mm and the length is cut per project.
How a sandwich panel is built
A sandwich panel has three layers: the outer steel skin, the insulating core and the inner steel skin. Skins are galvanized or pre-painted in RAL colours; the core insulates the panel and makes the two skins work together structurally.
Core types
| Core | Key property | Typical use |
|---|---|---|
| PIR | High thermal insulation, better fire behaviour than PUR | Industrial buildings, cold stores |
| PUR (polyurethane) | High thermal insulation | Roofs and walls, cold rooms |
| EPS | Economical and light | Agricultural and temporary buildings |
| Mineral wool | Non-combustible, sound insulation | Buildings with fire-safety requirements |
Sandwich panel thicknesses
Panels come in several standard thicknesses. Thicker panels insulate better but weigh and cost more. Unheated warehouses and agricultural buildings use thinner panels, heated buildings thicker ones, and chill and freezer stores the thickest. Mineral wool panels are thicker than PIR/PUR panels for the same insulation.
Sandwich panel sizes
- Effective width: the width a panel covers after overlap; typically 1000 mm.
- Length: cut per project in one piece; transport and installation set the upper limit.
- Ribs: roof panels have a trapezoidal upper skin (typically 3 or 5 ribs).
Which panel for which building?
| Building | Recommended solution |
|---|---|
| Unheated store, canopy, barn | Trapezoidal sheet or thin EPS panel |
| Heated factory, workshop, sports hall | PIR or PUR roof and wall panels |
| Chill and freezer store | Thick PIR or PUR cold room panel |
| Buildings with fire regulations | Mineral wool panel |
Installation and accessories
Sandwich panels are laid on steel or timber purlins with side overlaps and fixed with sealed screws. Ridge, gutter and eaves flashings on roofs, and corner and window trims on walls, are folded from sheet in the same colour. These details determine water-tightness and insulation as much as the panel itself. Screw count and purlin spacing are set in the project according to panel thickness and wind and snow loads.
Frequently asked
How thick is a sandwich panel? Panels come in several standard thicknesses; thickness is chosen by the required insulation and core.
Sandwich panel or trapezoidal sheet? Where thermal insulation is needed, sandwich panel; where it is not (open stores, canopies, agricultural buildings), trapezoidal sheet is more economical.
Can the panel colour be chosen? Yes; the outer skin can be pre-painted in RAL colours.
Roof or wall?
The roof sandwich panel drains water with its ribbed upper skin; the wall sandwich panel has flat or ribbed skins with exposed or concealed fixing. For cold stores see the cold room panel. For roofs that need no insulation, trapezoidal roofing sheet is more economical.
Sandwich panel prices
The price of sandwich panel depends on the core, panel thickness, skin thickness and colour, panel length and total area. Because steel and raw material prices change frequently, we do not publish a price list; current prices are given as a quote.
Request a quote for sandwich panel: just send us the panel type, core, thickness, colour, length and area.
This article was prepared by the İpek Metal technical team. Contact us for values specific to your project.