When specifying a steel floor deck system, one of the first decisions is whether composite or non-composite deck is required. Both are cold-formed steel profiles — but they perform very differently once concrete is placed. Choosing incorrectly can mean structural underperformance or unnecessary cost on your project.
What Is Composite Metal Deck?
Composite metal deck — sometimes called Type WR — is designed to bond structurally with the concrete poured on top of it. The deck's embossed ribs provide mechanical interlock with the cured slab, allowing the steel and concrete to act as a single structural unit under load.
This composite action enables longer spans, higher load capacities, and in most applications, eliminates the need for temporary shoring during construction. Common profiles are 1.5", 2", and 3" depth. The 2" profile is the most widely specified for commercial multi-story work.
What Is Non-Composite Metal Deck?
Non-composite deck — Type WF — serves as permanent steel formwork for concrete slabs. The key distinction: it does not bond structurally with the cured concrete. The slab carries floor loads independently, resting on the steel form. The deck stays in place permanently after the pour — no stripping required — but structurally the slab and deck are treated as separate elements.
Side-by-Side Comparison
| Factor | Composite Deck | Non-Composite Deck |
|---|---|---|
| Bond with concrete | Yes — acts as a composite unit | No — deck and slab are separate |
| Shoring during pour | Usually not required | May be required for longer spans |
| Typical applications | Multi-story offices, hospitals, high-rise | Parking garages, industrial slabs, mezzanines |
| Span capability | Longer spans via composite action | Determined by slab design alone |
| Standard finish | G90 galvanized | G60 or G90 galvanized |
| SDI designation | Type WR | Type WF |
When to Specify Composite Deck
Your structural engineer of record determines composite requirements based on loading and span layout. Composite deck is typically specified for:
- Multi-story office buildings and mixed-use developments
- Hospitals and healthcare facilities with elevated live load requirements
- High-rise residential construction
- Projects where shoring elimination is a schedule priority
- Long-span applications where concrete alone would require impractical thickness
When to Specify Non-Composite Deck
Non-composite deck is the right choice when composite action is not structurally required by the design:
- Ground-floor and on-grade platform slabs
- Parking structures where the slab design is self-sufficient
- Industrial mezzanine systems
- Building renovations with existing framing constraints
- Warehouses with heavy point loads requiring a thicker slab
The Bottom Line
The choice between composite and non-composite deck is a structural decision — your engineer of record will specify the type based on load tables, span requirements, and code compliance. As the deck supplier and manufacturer, our role is to deliver the specified profile precisely cut to your dimensions, certified to SDI and UL standards, on time.
We supply both composite deck and non-composite deck in 1.5", 2", and 3" profiles, gauges 16–22, with Grade 50 steel as standard across all orders. Have a project in the spec stage? Send us your details and we'll get you a quote.