Ordering steel plank for a scaffolding project seems simple enough—until you realise that the dimensions, thickness, load rating, and surface pattern all need to match the specific scaffold configuration, the expected loads, and the regulatory requirements for that project. Getting the specifications right on the first order saves weeks of delays, returns, and compatibility headaches.
This guide covers the standard steel plank size ranges, gauge specifications, load ratings, and the practical considerations that procurement teams face when ordering from a manufacturer or supplier. It also includes a note on how steel plank selection relates to formwork components such as the square column clamp system used elsewhere on the same project.
Standard Steel Plank Widths and Their Applications
Steel plank widths have been standardised internationally to match the transom spacing of common scaffolding systems. The two primary widths found in professional scaffolding supply catalogues are:
240 mm (9.5"): The most common width used in tube-and-fitting, ringlock, and cuplock scaffolding. A 240 mm steel plank provides adequate walkway width for a single worker passing through a scaffold bay. It is the standard choice for most general construction and maintenance scaffolding.
320 mm (12.6"): Used where wider walkways are needed for material handling, equipment access, or multiple workers in the same bay. The wider steel plank is common in industrial maintenance, heavy construction, and any application where workers carry tools or materials across the platform.
A less common variant is the 500 mm double-width steel plank, effectively two standard planks combined into a single wide unit. These are used in grandstand seating, stage platforms, and access routes where maximum walkway width with minimum assembly time is required. Most manufacturers offer this size as a special order item.
Length Options and Bay Size Matching
The length of a steel plank determines the span between scaffold transoms. Standard lengths range from 1,200 mm (4 feet) to 3,000 mm (10 feet) in 300 mm increments, although some manufacturers offer metric lengths in 500 mm increments as well.
The critical consideration when selecting steel plank length is that the unsupported span—the distance between transoms—must not exceed the manufacturer's rating for the plank gauge and width. A 1.5 m span is standard for a 240 mm steel plank with 1.5 mm gauge under normal construction loads. Longer spans require heavier-gauge planks or intermediate transoms.
One practical tip from experienced scaffold contractors: standardise on one or two lengths that match the most common bay sizes across your projects. This simplifies inventory management and reduces the likelihood of mismatched planks arriving on site from the supplier. A manufacturer that supplies a full range of lengths can accommodate custom orders, but standard sizes are almost always more cost-effective.
Steel Gauge (Thickness) Selection
The gauge or thickness of the steel sheet from which a steel plank is formed determines its stiffness, load capacity, and weight. Three standard gauges cover the majority of applications:
1.5 mm (0.06"): Standard-duty steel plank for general construction access, light material storage, and standard scaffolding configurations. Rated for UDL up to 200 kg per plank at 1.5 m span. This is the most commonly stocked gauge from steel plank manufacturers.
2.0 mm (0.08"): Heavy-duty steel plank for industrial applications, heavier material loads, and longer spans between transoms. Suitable for UDL of 270 kg per plank at 1.5 m span. The extra stiffness reduces deflection noticeably under load—an advantage when the plank serves as both a walkway and a material storage platform.
2.5 mm (0.10") or heavier: Extra-heavy-duty steel plank for specialised applications: bridge inspection platforms, heavy equipment maintenance, and high-load industrial access. These planks are noticeably heavier to handle and are typically used only where load analysis specifically requires the higher capacity.
Load Ratings and Classification
Steel plank load ratings are determined by the combination of gauge, width, and span, tested in accordance with BS EN 12811-1 (temporary works equipment). The standard defines three service classes:
Service Class 1 (SC1): Inspection and light access only—maximum 0.75 kN/m². Suitable for inspection-only steel plank applications where no materials are stored.
Service Class 2 (SC2): General construction access with light material storage—maximum 1.5 kN/m². This is the standard class for most construction scaffolding using steel plank.
Service Class 3 (SC3): Heavy construction where significant material storage is needed—maximum 2.0 kN/m². Requires heavy-gauge steel plank or reduced span lengths.
Anti-Slip Pattern and Surface Specifications
Steel plank surface patterns are not purely decorative features—they are specified based on the working environment. The most common pattern offerings from manufacturers include:
Diamond pattern pressed: Suitable for most applications. The raised diamonds channel water away from the walking surface. Pattern depth is typically 0.8–1.2 mm on standard-gauge steel plank.
Perforated with raised edges: Preferred for wet environments, offshore, and food processing. Water drains through holes rather than pooling. The raised hole edges provide additional grip points.
Flat surface with serrated edge coating: Used in indoor controlled environments or where the steel plank may be removed and reinstalled frequently—the smooth surface is easier to slide into scaffold brackets.
Coordination with Square Column Clamp Formwork Systems
On a typical building construction project, steel plank products provide the access platforms around the structure while square column clamp systems are used for the column formwork. These two product categories are often sourced from the same supplier or manufacturer. When ordering both, consider the following coordination points:
The steel plank lengths should match the scaffold bay widths used to access the column formwork area—standard 2.4 m or 3.0 m planks typically work well around a column grid.
If the square column clamp adjustment range requires specific clearances for the formwork panels, ensure the steel plank platform level is positioned to allow sufficient working height above the clamp installation area.
A supplier that provides both square column clamp and steel plank products can often coordinate delivery schedules and offer combined pricing that simplifies procurement for the project.
FAQ: Steel Plank Sizes and Specifications
What is the most common steel plank size used in construction scaffolding?
The most commonly stocked size across steel plank suppliers is 240 mm wide × 1.5 m long, with 1.5 mm gauge material and a diamond-pressed anti-slip surface. This size matches standard scaffold bay widths and is adequate for Service Class 2 loads, which covers the majority of general construction access applications.
Can steel planks from different manufacturers be mixed on the same scaffold?
As long as the steel plank dimensions (width, length, and locking mechanism type) are consistent, mixing planks from different suppliers is generally acceptable for temporary works use. However, for traceability and quality assurance, most contractors prefer to source all steel plank products for a single project from one manufacturer to ensure consistent dimensions, load ratings, and coating quality.
How do I determine the required steel plank gauge for a given span?
Refer to the manufacturer's load-span table for the specific steel plank width you are using. As a general guide: 1.5 mm gauge planks are suitable for spans up to 1.5 m under SC2 loads. For spans exceeding 1.5 m, or if SC3 loads are expected, specify 2.0 mm or heavier steel plank. When in doubt, a structural engineer with temporary works experience should confirm the gauge selection.
Conclusion
Specifying steel plank correctly requires attention to width, length, gauge, load rating, and surface pattern—each matched to the scaffold configuration and working conditions on site. Standard sizes (240 mm × 1.5 m in 1.5 mm gauge) cover most general construction needs, while heavy-duty or specialised applications require careful selection from the manufacturer's product range. On projects where square column clamp formwork systems are also used, coordinating both product types through a single supplier can simplify procurement, ensure delivery compatibility, and potentially improve pricing through combined orders.
References
British Standards Institution. BS EN 12811-1:2019 Temporary Works Equipment—Scaffolds—Performance Requirements and General Design. BSI.
International Organization for Standardization. ISO 1461:2019 Hot Dip Galvanized Coatings on Iron and Steel Articles. ISO.
National Access and Scaffolding Confederation. NASC TG20:21 Design Guide for Tube and Fitting Scaffolding. NASC.
Construction Industry Research and Information Association. CIRIA C652: Safer Surfaces to Walk On. CIRIA.
American Society of Civil Engineers. ASCE 37: Design Loads on Structures During Construction. ASCE.