Sandwich Panel Inner Skin Dimensions, Rib Profiles, Steel Gauges, and Production Specifications
Sandwich Panel Inner Skin Dimensions, Rib Profiles and Specifications
The Sandwich Panel Inner Skin is the internal metal sheet used in insulated sandwich panels. It forms the interior surface of the panel and provides structural support for the insulation core while creating a clean internal wall or ceiling finish.
Sandwich panels consist of three main components:
• outer metal skin
• insulation core
• inner metal liner skin
The inner skin plays an important role in panel strength, insulation support, and internal building appearance.
Sandwich panels are widely used in modern construction because they provide thermal insulation, structural rigidity, and rapid installation.
Typical applications include:
• cold storage buildings
• warehouses
• food processing plants
• pharmaceutical facilities
• industrial buildings
• agricultural buildings
• clean room construction
The inner skin is manufactured using roll forming machines that produce lightly profiled or flat metal sheets designed to bond with insulation cores.
This guide provides a detailed technical overview of sandwich panel inner skin dimensions, rib profiles, steel gauges, coil width requirements, and production specifications used by engineers, panel manufacturers, and construction professionals.
What is a Sandwich Panel Inner Skin
A sandwich panel inner skin is the interior metal sheet that forms the inside surface of an insulated sandwich panel.
The inner skin performs several important functions:
• supports the insulation core
• increases panel structural strength
• provides a finished interior surface
• protects insulation materials
• improves fire and moisture resistance
Unlike the outer skin, the inner skin typically uses shallower rib patterns or flat surfaces to create a clean internal wall finish.
Sandwich Panel Construction
A typical insulated sandwich panel consists of three layers.
Panel structure:
Outer Skin (profiled metal sheet)
Insulation Core (PU / PIR / EPS / Mineral Wool)
Inner Skin (liner metal sheet)
The inner skin is bonded to the insulation core during the manufacturing process.
Standard Sandwich Panel Inner Skin Dimensions
The inner skin is typically manufactured with shallow ribs or micro ribs to improve bonding with insulation cores.
Typical dimensions include:
Specification
Typical Measurement
Coverage Width
1000 – 1200 mm
Overall Width
1050 – 1250 mm
Rib Height
5 – 12 mm
Rib Pitch
100 – 250 mm
Panel Length
Custom roll formed
Coverage width refers to the installed width of the panel.
Inner Skin Rib Layout
The inner skin typically uses shallow ribs or micro rib patterns designed to improve rigidity and bonding with the insulation core.
Typical surface designs include:
• micro rib pattern
• shallow trapezoidal ribs
• lightly profiled liner panels
• flat liner surfaces
Typical rib dimensions include:
Feature
Measurement
Rib height
5 – 12 mm
Rib spacing
100 – 250 mm
Rib top width
20 – 40 mm
Rib base width
40 – 80 mm
These shallow ribs increase panel rigidity while maintaining a smooth interior appearance.
Steel Gauge Range for Sandwich Panel Inner Skins
The thickness of the inner skin is typically slightly lighter than the outer skin.
Typical thickness ranges include:
Gauge
Thickness
Typical Application
29 gauge
0.35 mm
Light insulation panels
27 gauge
0.40 mm
Agricultural buildings
26 gauge
0.45 mm
Industrial buildings
24 gauge
0.60 mm
Heavy-duty panels
Thicker inner skins improve panel strength and durability.
Insulated Panel Thickness with Core Material
The overall sandwich panel thickness depends on the insulation core thickness rather than the skin thickness.
Typical panel thicknesses include:
Panel Thickness
Typical Application
40 mm
Internal partition panels
50 mm
Commercial wall panels
75 mm
Industrial buildings
100 mm
Cold storage
150 mm
Freezer panels
200 mm
High-performance insulation panels
The inner skin thickness remains relatively constant across different panel thicknesses.
Coil Width Requirements for Inner Skins
Steel coil must be slit to the correct width before entering the roll forming machine.
Typical coil widths include:
Panel Coverage
Coil Width
1000 mm panel
1100 – 1120 mm coil
1150 mm panel
1250 – 1270 mm coil
1200 mm panel
1300 – 1320 mm coil
Additional material is required to form ribs and side seams.
Materials Used for Sandwich Panel Inner Skins
Inner skins are typically manufactured using corrosion-resistant coated steel.
Common materials include:
Pre-painted galvanized steel
Galvanized steel
Galvalume steel
Aluminum
Pre-painted steel is often used when a clean internal appearance is required.
Insulation Core Materials
The insulation core is bonded between the outer and inner skins.
Common insulation materials include:
Polyurethane (PU)
Polyisocyanurate (PIR)
Expanded Polystyrene (EPS)
Mineral Wool (Rock Wool)
Each material provides different thermal and fire performance characteristics.
Industries Using Sandwich Panel Systems
Sandwich panels are widely used across industrial and commercial construction sectors.
Typical applications include:
Cold storage facilities
Food processing plants
Pharmaceutical manufacturing
Industrial warehouses
Agricultural buildings
Clean room facilities
The inner skin provides a clean interior surface for these environments.
Roll Forming Machines Used to Produce Inner Skins
Inner skins are produced using roll forming machines integrated into sandwich panel production lines.
Typical machine specifications include:
Number of forming stations
14 – 20 stations
Roller material
Hardened tool steel
Machine speed
10 – 20 meters per minute
Drive system
Gearbox drive
Cutting system
Flying shear
Control system
PLC automatic length control
These machines produce the inner metal sheet before lamination with insulation.
Sandwich Panel Production Lines
Sandwich panel manufacturing typically uses automated continuous production lines.
Typical line components include:
Uncoiler
Roll forming machine
Foaming or lamination system
Double belt laminator
Cutting system
Stacking system
The inner and outer skins are produced before insulation bonding.
Common Manufacturing Problems
Manufacturing issues can occur if the production line is not properly adjusted.
Common problems include:
core delamination
panel distortion
rib deformation
adhesive bonding failure
Proper process control ensures consistent panel quality.
Frequently Asked Questions
What is a sandwich panel inner skin?
A sandwich panel inner skin is the interior metal sheet that forms the inside surface of an insulated sandwich panel.
What thickness is used for sandwich panel inner skins?
Typical thickness ranges from 0.35 mm to 0.60 mm steel.
What width are sandwich panel inner skins?
Coverage widths typically range between 1000 mm and 1200 mm.
What materials are used for inner skins?
Common materials include pre-painted steel, galvanized steel, galvalume steel, and aluminum.
Where are sandwich panels used?
They are widely used in cold storage facilities, warehouses, food processing plants, and industrial buildings.
Conclusion
The sandwich panel inner skin is an essential component of insulated sandwich panel systems. It provides structural support for the insulation core while creating a durable interior surface.
Understanding inner skin dimensions, rib profiles, steel gauges, coil width requirements, and production specifications is essential for engineers, panel manufacturers, and building designers.
Roll forming machines used in sandwich panel production allow manufacturers to efficiently produce inner liner sheets that bond with insulation cores to form high-performance insulated wall and roof panels.