By Hu Xianzhe, Cold Roll Forming Technical Engineer at ZTRFM | Last Updated: September 15, 2026
A contractor in Indonesia called me during a floor deck installation. The sheets had arrived, and his crew started laying them down. Then he noticed the embossing pattern was different from what the structural engineer had specified. The engineer had designed for a specific bond strength between the concrete and the steel deck, and the embossing on these sheets was too shallow. The whole shipment had to go back.
I'mHu Xianzhe, Cold Roll Forming Technical Engineer at ZTRFM. I've supervised floor deck installations on warehouses, high-rise offices, and parking structures. Floor decking looks simple -- it's just corrugated steel sheet with some bumps on it -- but the details matter. Here's what you need to know about floor deck profiles, embossing, and the machines that make them.
What Is Steel Floor Decking?
Steel floor decking (also called metal decking, composite deck, or corrugated steel deck) serves two purposes:
- During construction: It acts as permanent formwork. Workers pour concrete directly onto it. No need for wooden forms.
- After curing: The embossments on the deck bond with the concrete, creating a composite slab. The steel deck becomes the bottom tensile reinforcement.
This system is faster and lighter than traditional reinforced concrete slabs. It's the standard for multi-story steel-framed buildings.
Three Main Profile Types
1. Open Rib (Non-Composite)
Simple trapezoidal ribs with no embossing. Used as formwork only -- the steel doesn't bond with concrete. You still need conventional rebar in the slab.
Common profiles: 1.0mm, 1.2mm, 1.5mm material thickness. Rib height 38mm or 50mm. Typical coverage width 915mm or 1000mm.
Best for: Non-composite slabs, temporary works, or where local codes don't recognize composite action.
2. Closed Rib with Embossing (Composite)
The most common composite deck profile. Trapezoidal ribs with a closed (narrowed) bottom and embossments rolled into the web and flange. The embossments provide mechanical interlock with concrete.
Common profiles: Rib height 38mm, 50mm, or 75mm. Material thickness 0.8-1.5mm (most common: 1.0mm and 1.2mm). Width 915mm or 1000mm. The 75mm profile is for longer spans (up to 3.5m unshored).
Embossing requirements: Depth 2-3mm, spacing 50-70mm. The embossing must be consistent -- if it's too shallow, the bond fails; if it's too deep, it distorts the profile. This is controlled by the embossing roller on the machine.
3. Dovetail (Re-entrant)
A profile where the rib openings narrow at the top (like a dovetail joint). The narrow top traps concrete, creating excellent mechanical bond even without deep embossing. Popular in North America (Vulcraft, Verco profiles).
Common profiles: Rib height 38mm or 50mm. Width 915mm (36 inches, standard US width).
Machine Features That Matter
| Feature | Why It Matters |
|---|---|
| Embossing roller | Creates the mechanical bond surface. Must be adjustable for depth. If the machine doesn't have this, you can't make composite deck. |
| Number of stands | Floor deck profiles have deeper ribs (38-75mm) than roofing (15-35mm). You need 18-24 stands to form without cracking at the bends. |
| Material thickness range | Floor deck uses heavier material (0.8-1.5mm vs 0.3-0.8mm for roofing). The machine frame, shafts, and cut-off must be rated for the thicker material. |
| Cut-off method | For 1.5mm material, a hydraulic flying cut-off is standard. A mechanical (crank) cut-off may struggle with thick material at high speed. |
| Embossing pattern flexibility | If you export to different markets, the embossing pattern may need to match local standards (e.g., SDI in the US, EN ISO in Europe). Make sure the embossing roller is replaceable. |
Span Guide (Unshored Construction)
The span is how far the deck can span between beams without temporary shoring during concrete pouring. This depends on profile, thickness, and concrete weight.
| Profile Height | Thickness | Max Span (1-span) | Max Span (2-span) |
|---|---|---|---|
| 38mm | 0.8mm | 1.8m | 2.2m |
| 38mm | 1.0mm | 2.2m | 2.7m |
| 50mm | 1.0mm | 2.5m | 3.0m |
| 50mm | 1.2mm | 2.8m | 3.4m |
| 75mm | 1.0mm | 3.0m | 3.6m |
| 75mm | 1.2mm | 3.5m | 4.2m |
These are conservative values for normal-weight concrete (2400 kg/m³) and a 120mm total slab thickness. Always verify with your structural engineer and local code.
Quick Q&A
Can I use a roofing machine to make floor deck? No. Floor deck requires thicker material, deeper ribs, and embossing. A roofing machine's shafts aren't rated for 1.5mm material, and it won't have an embossing roller.
What's the difference between galvanized and galvalume for floor deck? Both work. Galvanized (Z275) is the standard. Galvalume (AZ150) is more corrosion-resistant but more expensive. For floor deck embedded in concrete, corrosion isn't a major concern, so galvanized is sufficient.
Do I need shear studs? If the deck is composite and the design requires composite action with the steel beam (not just the concrete), yes. Shear studs are welded through the deck into the beam. The deck profile must accommodate stud placement -- check that the rib width allows it.
What machine speed should I expect? 8-15 m/min for floor deck machines. Slower than roofing (15-25 m/min) because of the thicker material and deeper forming.
Frequently Asked Questions (FAQ)
Can a roofing machine make steel floor deck?
No. Floor deck requires thicker material, deeper ribs and embossing. Roofing-machine shafts are not rated for 1.5 mm material and roofing machines do not include the required embossing roller.
Should galvanized or galvalume steel be used for floor deck?
Both can work. The article identifies galvanized Z275 as standard and notes that AZ150 galvalume is more corrosion-resistant but more expensive; galvanized is generally sufficient for deck embedded in concrete.
Are shear studs required?
They are required when the structural design calls for composite action with the steel beam. The studs are welded through the deck into the beam, and the rib must be wide enough for stud placement.
What speed is typical for a floor deck machine?
The article gives a typical speed of 8-15 m/min, slower than roofing lines because floor deck uses thicker material and deeper forming.
