Galvalume Metal Decking Guide Steel Deck Coatings Sizes Gauges and Corrosion Resistance

Galvalume Metal Decking Guide

Galvalume metal decking is a high performance steel decking material designed for superior corrosion resistance, especially in harsh environments such as coastal, industrial, and high humidity locations. It combines the strength of steel with an advanced aluminum zinc coating, offering extended service life compared to standard galvanised steel.

Galvalume decking is widely used in roofing systems, industrial buildings, and specialized applications where long term durability is critical.

This guide provides a full technical and commercial overview of Galvalume metal decking, including coating composition, types, sizes, gauges, performance characteristics, applications, and installation.

What Is Galvalume Metal Decking

Galvalume metal decking is steel decking coated with an aluminum zinc alloy, typically composed of:

55 percent aluminum
43.4 percent zinc
1.6 percent silicon

This coating provides enhanced corrosion resistance by combining the barrier protection of aluminum with the sacrificial protection of zinc.

How Galvalume Coating Works

Barrier Protection

Aluminum creates a protective surface
Prevents moisture penetration

Sacrificial Protection

Zinc protects exposed steel areas
Reduces corrosion at edges

Heat Resistance

Reflects heat
Improves performance in high temperature environments

Types of Galvalume Metal Decking

Galvalume Roof Decking

Profile Details

B deck and N deck profiles
Designed for roofing systems

Applications

Commercial roofs
Industrial buildings
Coastal structures

Galvalume Composite Decking

Profile Details

Embossed ribs
Designed for concrete bonding

Applications

Floor systems in harsh environments

Galvalume Non Composite Decking

Profile Details

Structural steel deck
Used without concrete

Applications

Platforms
Mezzanines

Galvalume Corrugated Decking

Profile Details

Wave profile
Lightweight

Applications

Agricultural and light industrial buildings

Deck Sizes and Dimensions

Deck Depth

1.5 inch standard deck
2 inch intermediate deck
3 inch deep deck

Sheet Width

Typically 24 inch to 36 inch

Sheet Length

Custom cut
Typically 6 ft to 40 ft

Rib Profile

Designed for structural strength and drainage

Gauges and Thickness

Common Gauges

22 gauge light duty
20 gauge standard
18 gauge heavy duty
16 gauge extra heavy duty

Thickness Selection

Based on span
Based on load requirements
Based on environmental exposure

Galvalume vs Galvanised Metal Decking

Key Differences

Corrosion Resistance

Galvalume offers better long term protection

Heat Performance

Galvalume reflects heat more effectively

Coastal Performance

Galvalume performs better in coastal environments

Cost

Slightly higher than galvanised steel

Coating Performance in Different Environments

Dry Environments

Both galvanised and Galvalume perform well

Humid Environments

Galvalume offers improved durability

Coastal Environments

Galvalume is preferred

Industrial Environments

Galvalume performs better against chemical exposure

Load Capacity and Structural Performance

Load Types

Dead load
Live load
Environmental loads
Concrete load in composite systems

Structural Performance

Same strength as standard steel decking
High strength to weight ratio

Span Capabilities

Depends on deck profile and gauge
Deep profiles allow longer spans

Applications of Galvalume Metal Decking

Commercial Buildings

Roofing systems
Structural decks

Industrial Facilities

Factories
Warehouses

Coastal Construction

Marine environments
High humidity areas

Agricultural Buildings

Storage structures

Infrastructure Projects

Bridges
Platforms

Installation Process

Step by Step

Deck Placement

Install on structural frame
Align panels

Fastening

Weld or screw to supports
Secure side laps

Composite Systems

Install shear studs
Pour concrete

Roof Systems

Install insulation and membranes

Installation Best Practices

Protect Coating

Avoid scratching or damaging surface

Proper Handling

Prevent contamination

Secure Fixing

Ensure structural stability

Advantages of Galvalume Metal Decking

Superior corrosion resistance
Long service life
Excellent heat reflectivity
Ideal for harsh environments

Limitations

Higher cost than galvanised steel
Not ideal for direct contact with certain materials such as wet concrete without proper design
Requires careful handling to avoid coating damage

Common Problems and Solutions

Edge Corrosion

Cause

Exposed cut edges

Solution

Use proper edge protection

Coating Damage

Cause

Handling or installation

Solution

Protect during installation

Chemical Exposure

Cause

Industrial environments

Solution

Use additional coatings if required

Cost of Galvalume Metal Decking

Cost Factors

Coating type
Deck type
Gauge thickness
Project size

General Cost Trends

Higher initial cost than galvanised
Lower long term maintenance cost

How to Choose Galvalume Metal Decking

Consider Environment

Ideal for coastal and harsh environments

Consider Application

Roofing or structural deck

Consider Load Requirements

Structural loads

Consider Budget

Balance upfront cost and lifespan

FAQ Galvalume Metal Decking

What is Galvalume metal decking
It is steel decking coated with aluminum zinc alloy

Is it better than galvanised steel
Yes in many environments especially coastal

Can it be used for floors
Yes with proper design

What gauges are available
Typically 22 to 16 gauge

How long does it last
Longer than standard galvanised steel in harsh environments

Conclusion

Galvalume metal decking is a high performance solution for projects requiring superior corrosion resistance and long term durability. Its advanced coating technology makes it ideal for demanding environments while maintaining the strength and versatility of steel decking systems.

Selecting the correct deck type, gauge, and installation method ensures optimal performance and extended service life.