What is composite metal decking?
Composite metal decking is a cold-formed steel profile that forms the load-bearing base of a composite slab or floor system. Its structural behavior is based on the collaboration between steel, which absorbs tensile forces, and structural concrete, which resists compression.
During the construction phase, the deck acts as permanent formwork, supporting the weight of fresh concrete, reinforcement, and construction loads without the need for traditional formwork. After curing, both materials work together, creating a composite section with high stiffness and load-bearing capacity.
This system makes it possible to reduce the total slab depth (typically from 120 mm), achieve lightweight solutions, and optimize execution times compared to conventional systems.
Composite decks are generally manufactured in galvanized steel or with advanced corrosion-protection coatings. They are supplied in different thicknesses and rib heights to meet the project’s structural requirements. Their geometry incorporates embossments that ensure proper load transfer between the steel and the concrete.
How does composite metal decking work?
The structural behavior of composite decking develops in two distinct phases:
1. Formwork phase
The ribbed deck rests on the supporting structure (steel, concrete, or composite) and acts as a temporary load-bearing element. At this stage, it supports the weight of fresh concrete and construction overloads.
The rib shape provides the stiffness needed to limit deflections and, in certain configurations, may allow solutions without intermediate propping.
2. Composite phase
Once the concrete has hardened, the embossments in the profile ensure the transfer of forces between both materials. The deck works as tensile reinforcement, while the concrete forms the compressed head of the section.
The result is an optimized composite section, with greater load-bearing capacity and improved in-service performance against deflection and vibration. Final performance (allowable deflections, fire resistance, or need for propping) depends on the selected profile and the adopted structural configuration.
When is composite metal decking used?
Composite decking is used in projects where a lightweight, efficient, and fast-to-install structural solution is required. Its versatility allows it to be used both in new construction and in rehabilitation projects.
Common applications include:
Industrial and logistics buildings, where it reduces assembly times and simplifies execution on steel structures.
Office buildings and shopping centers, enabling intermediate floors with weight control and optimized clear heights.
Residential buildings and extensions, especially when reducing loads on the existing structure is necessary.
Parking structures and sports facilities, due to their good structural performance and adaptability to fire-resistance requirements.
In addition to its load-bearing function, the system facilitates the integration of services, reduces auxiliary on-site operations, and streamlines the construction process.
Types of Incoperfil composite deck profiles
Incoperfil offers different composite deck profile models designed to adapt to various structural requirements:
INCO 70.4 Composite: medium rib profile indicated for shallow slabs or where no specific fire-resistance requirements apply.
INCO 100.3 Composite: higher profile suitable for medium spans and solutions without propping in certain configurations.
INCO 100.3 R Composite: optimized variant for higher fire-resistance requirements, allowing configurations with increased concrete cover.
Profile selection must be carried out through structural analysis in accordance with current regulations and considering project loads.
Conclusion
Composite metal decking is the essential element of the steel–concrete composite system in composite floor slabs. Its ability to act as temporary support and later as an integrated structural component helps optimize weight, stiffness, and construction efficiency, making it a well-established technical solution in industrial and commercial construction.
Incoperfil Technical Manual
For a complete definition of the system, design criteria, calculation bases, resistance tables, construction details, and installation procedures, consult the Incoperfil Composite Slab Technical Manual, available upon registration in the Documentation section of the website.
Last update: February 2026
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The technical content of this article is part of the Composite Slab Technical Manual and the documentation registered by Incoperfil in ColorIURIS (Record No. 1-INCOPERFIL-12.2025).