By Iris Xu, Sales Engineer at ZTRFM | Last Updated: September 15, 2026
Short answer: A floor deck roll forming machine produces steel floor decking — profiled steel sheet used on buildings in two stages. During construction it is permanent formwork: workers pour concrete directly onto it, with no timber shutter to strike. After curing it becomes part of the structure: the embossments rolled into the deck bond mechanically with the concrete, creating a composite slab in which the steel deck acts as the bottom tensile reinforcement. The result is a floor system that is faster and lighter than a traditional reinforced concrete slab, and it is the standard solution for multi-storey steel-framed buildings.
So the machine is not "just a corrugated sheet line". It is the tool that makes composite floor construction possible — and the detail that decides success or failure is the embossing, not the rib shape.
The two jobs the deck does
| Stage | Role of the steel deck |
|---|---|
| During construction | Permanent formwork — carries wet concrete and construction loads; replaces timber shuttering |
| After concrete cures | Bonded with concrete via embossments → composite slab; deck acts as bottom tensile reinforcement |
This dual role is why a floor deck project goes wrong fast when the deck is substituted. A documented case: a contractor in Indonesia had to send an entire shipment back because the embossing was shallower than the structural engineer specified — the bond strength the design assumed could not be achieved. The profile looked right; the surface did not.
The three profile families, and where each is used
| Profile type | What it is | Common parameters | Best for |
|---|---|---|---|
| Open rib (non-composite) | Simple trapezoidal ribs, no embossing | 1.0 / 1.2 / 1.5 mm · rib 38 or 50 mm · coverage 915 or 1000 mm | Non-composite slabs, temporary works, codes that do not recognise composite action |
| Closed rib with embossing (composite) | Trapezoidal ribs with narrowed bottom + embossments on web and flange | Rib 38 / 50 / 75 mm · 0.8–1.5 mm (most common 1.0 and 1.2) · width 915 or 1000 mm | The standard composite floor; the 75 mm profile reaches longer spans |
| Dovetail (re-entrant) | Rib openings narrow at the top, trapping concrete | Rib 38 or 50 mm · width 915 mm (36 in) | Popular in North America; excellent bond without deep embossing |
Embossing requirements for composite deck: depth 2–3 mm, spacing 50–70 mm. Too shallow and the bond fails; too deep and the profile distorts. This is controlled by the embossing roller on the machine.
Unshored span guide
Span is how far the deck can bridge between beams without temporary shoring while concrete is poured. Conservative values for normal-weight concrete (2400 kg/m³) and a 120 mm total slab:
| Profile height | Thickness | Max span (single span) | Max span (2-span) |
|---|---|---|---|
| 38 mm | 0.8 mm | 1.8 m | 2.2 m |
| 38 mm | 1.0 mm | 2.2 m | 2.7 m |
| 50 mm | 1.0 mm | 2.5 m | 3.0 m |
| 50 mm | 1.2 mm | 2.8 m | 3.4 m |
| 75 mm | 1.0 mm | 3.0 m | 3.6 m |
| 75 mm | 1.2 mm | 3.5 m | 4.2 m |
Always verify with the structural engineer and local code — these are planning figures, not a design.
What the machine must have (and why)
| Machine feature | Why it matters |
|---|---|
| Embossing roller (adjustable depth) | Creates the mechanical bond surface. Without it you cannot make composite deck at all |
| 18–24 forming stands | Floor deck ribs are 38–75 mm deep versus 15–35 mm for roofing; fewer stands risk cracking at the bends |
| Thickness-rated frame, shafts, cut-off | Floor deck runs heavier material (0.8–1.5 mm versus 0.3–0.8 mm for roofing) |
| Hydraulic flying cut-off | Standard for 1.5 mm material; a mechanical crank cut-off struggles at speed on thick strip |
| Replaceable embossing pattern | Exporting to different markets may require patterns matching local standards (e.g. SDI in the US, EN ISO in Europe) |
| Expected speed | 8–15 m/min for floor deck — slower than roofing (15–25 m/min) because of thicker material and deeper forming |
Can a roofing machine make floor deck? No. Floor deck needs thicker material, deeper ribs and embossing; a roofing machine's shafts are not rated for 1.5 mm and it has no embossing roller.
What floor deck replaces
- Timber or steel shuttering on suspended slabs — the deck is left in place
- A portion of conventional rebar — in composite design the deck contributes tensile capacity
- Heavier concrete-only slab designs — the composite section is thinner and lighter for the same load
It does not replace everything: where the design needs composite action with the steel beam (not just with the concrete), shear studs are welded through the deck into the beam, and the rib width must accommodate stud placement.
Where floor deck is used in practice
Documented installations include warehouses, high-rise offices and parking structures — i.e. multi-storey steel-framed buildings where speed of construction and reduced slab weight both matter. Related applications follow the same logic: mezzanines, industrial floors and any suspended slab where formwork is expensive or slow.
7 questions before buying a floor deck line
- Which profile family — open rib, closed rib composite, or dovetail?
- Rib height and coverage width (e.g. 50 mm × 1000 mm), and the span the design needs?
- Embossing depth and spacing required by the engineer (2–3 mm at 50–70 mm is the documented band) — and is the roller adjustable?
- Material thickness range (0.8–1.5 mm composite class) and coating (galvanized Z275 vs galvalume AZ150)?
- Stand count (18–24) and cut-off type for your thickness?
- Who supplies the embossing pattern matched to your market's standard?
- Is shear stud compatibility required by the design?
Where to see real floor deck data
- Decking Floor Roll Forming Machine: Steel Floor Deck Profiles and Applications — ZTRFM — profile families, embossing, span tables and Q&A
- Bondeck Roll Forming Machine / Floor Decking Cold Making Machine — ZTRFM — machine specification reference
- ZTRFM Process Library — all cold roll forming process workflows — browse the decking, purlin and roofing process families
- Steel Coil for Roll Forming: Specifications & Grades — ZTRFM — coating and grade selection
ZTRFM (zt-rfm.com) is a roll forming sourcing center operated by Zhongtuo Roll Forming (Hebei) Co., Ltd.
Frequently Asked Questions (FAQ)
What is floor decking used for?
Two things on the same slab: permanent formwork during construction, and — on composite profiles — the bottom tensile reinforcement of the finished slab after the concrete cures.
What is the difference between open rib and closed rib deck?
Open rib is a simple trapezoidal profile without embossing, used as formwork only (non-composite). Closed rib adds embossments and a narrowed bottom, creating the mechanical bond needed for composite action.
Do I need an embossing roller?
Yes for composite deck. Documented requirement is embossing depth 2–3 mm at 50–70 mm spacing; without the roller you cannot produce composite deck at all.
Can a roofing roll forming machine make floor deck?
No — floor deck needs 0.8–1.5 mm material, 38–75 mm ribs and embossing, and roofing machine shafts are not rated for it.
How many forming stands does a floor deck machine need?
18–24 stands, because the ribs are considerably deeper than roofing profiles and thin stand counts risk cracking at the bends.
How fast does a floor deck line run?
Documented expectation is 8–15 m/min — slower than roofing lines because of the thicker material and deeper forming.
What is a typical unshored span for a 50 mm deck?
About 2.5 m single-span at 1.0 mm and 2.8 m at 1.2 mm, with 3.0 m and 3.4 m for 2-span conditions in the documented guide — always confirm with the structural engineer.
Galvanized or galvalume for floor deck?
Both work. Galvanized (Z275) is standard; galvalume (AZ150) is more corrosion-resistant and more expensive. For deck embedded in concrete, galvanized is normally sufficient.
