The main types of grating fall into three groups. By construction, a grating uses welded, electroforged, pressure-locked, swage-locked or riveted joints. By material, they come in mild steel, stainless steel, aluminium or fibre-reinforced plastic (FRP). By surface and form, the options are not equivalent to each other: plain and serrated describe the top surface, stair tread and heavy-duty describe the form and the duty a panel is built for, and plank and expanded metal are sheet-based alternatives to conventional bar grating.
This guide covers the structural and floor gratings you find on platforms, walkways and stairs. It does not cover optical diffraction gratings.
The types, materials and surfaces below are general industry classifications. No single manufacturer supplies every combination. Aparna Rollform manufactures manual welded gratings and step gratings; the specification table near the end of this article lists that verified range.
A grating is an assembly of load-bearing bars and cross bars joined by welding, pressure-locking or riveting to form an open grid. The grid carries loads while letting light, air, water and small debris pass through. Because most of the surface is open, a grating weighs far less than a solid plate covering the same area.
Engineers and fabricators often use “grating”, “bar grating” and “steel grating” interchangeably. Strictly, bar grating is the most common family, and steel is its most common material.
Every bar grating shares the same basic parts. Knowing them makes any grating specification easier to read.
| Part | What it does |
|---|---|
| Bearing bar | The main flat bar that carries the load. Bearing bars run in the span direction, from one support to the next |
| Cross bar | The bar that runs across the bearing bars and holds them at a fixed spacing. It keeps the bearing bars upright under load |
| Pitch | The centre-to-centre distance between bearing bars, or between cross bars |
| Span | The length of the panel in the direction of the bearing bars – the distance the grating bridges between supports |
| Width | The panel dimension measured across the bearing bars |
| Banding (edge bar) | A flat bar welded across the cut ends of the bearing bars to close and stiffen the panel edge |
| Toe plate | An upstand along an open edge that stops tools and objects from rolling off a platform |
| Nosing | A slip-resistant front edge on a stair tread that makes the step edge easy to see |
Suppliers describe gratings in three independent ways. A single product usually needs all three to describe it fully – for example, a hot-dip galvanised, serrated, electroforged mild steel grating.
| Classification | What it describes | Common options |
|---|---|---|
| Construction | How the bars join | Welded, electroforged, pressure-locked, swage-locked, riveted |
| Material | Bar material | Mild steel, stainless steel, aluminium, FRP |
| Surface and form | How the top surface, the panel form and the duty differ – these are not equivalent categories | Surface: plain, serrated. Form and duty: stair tread, heavy-duty. Sheet-based alternatives: plank, expanded metal |
Every classification here describes the industry as a whole, not one supplier’s catalogue.
The joining method decides how rigid the panel is, how it looks, and how easily a fabricator can cut it to a custom shape.
Step grating does not appear in this group because it describes where a panel goes, not how the bars join – a fabricator can weld, electroforge or press-lock a step grating. It appears under surface and form below.
In a welded grating, cross bars join the bearing bars with a weld at every intersection. The result is a rigid, one-piece panel. Welding suits carbon steel and stainless steel, and industrial floors and platforms use it widely.
Manual welded grating uses a welder rather than a production machine to join each intersection. This route suits odd shapes, circular platforms around tanks, large cut-outs and small batches that do not justify machine set-up. Weld quality and finish depend on the fabricator’s process control, so ask for welding procedure details on critical work. Aparna Rollform manufactures manual welded gratings.
Electroforged grating is a machine-made welded grating. A resistance-welding machine applies high electric current and hydraulic pressure at the same time, fusing the cross bar into the top edge of each bearing bar without filler metal. The cross bar is usually a twisted square bar.
Because a machine repeats every joint, electroforged panels come out uniform and suit high-volume standard sizes for walkways, platforms and trench covers. Custom shapes still need cutting, banding and sometimes manual welding after forging.
Pressure-locked (press-locked) grating has no welds. A press forces the cross bars into notches in the bearing bars under very high pressure, locking them in place. The top surface sits flush, and the pattern looks clean and even.
Architects use pressure-locked grating for façades, sunscreens, ceilings, fencing and pedestrian areas where appearance matters. It also allows close bar spacing.
Swage-locked grating uses hollow or tubular cross bars that pass through holes punched in the bearing bars. A machine then swages (deforms) the cross bars on each side of every bearing bar, locking the grid mechanically. Manufacturers commonly apply this method to aluminium grating, including lightweight I-bar sections.
Riveted grating combines straight bearing bars with bent connecting bars, joined by rivets at each contact point. The bent bars create a distinctive zig-zag pattern. The US metal bar grating standard (ANSI/NAAMM MBG 531) still lists riveted grating as a standard type, and it has a long history in areas with rolling loads. Indian grating suppliers list it far less often than welded grating.
Material sets corrosion resistance, weight and stiffness. The construction method does not change these properties – a welded stainless grating and a press-locked stainless grating resist corrosion in the same way. The four materials below cover the industry; individual manufacturers work with only some of them.
| Material | Key characteristics | Typical applications |
|---|---|---|
| Mild (carbon) steel | High stiffness and strength; economical compared with stainless steel and aluminium; needs hot-dip galvanising or paint outdoors | Industrial platforms, walkways, pipe racks, stairs, trench covers |
| Stainless steel (304, 316) | Corrosion resistant without a coating; grade 316 contains molybdenum and resists chlorides better than 304 | Food, dairy, pharmaceutical, chemical and coastal installations |
| Aluminium | About one-third the weight of steel and naturally corrosion resistant; electrically conductive; its lower stiffness means more deflection than steel for the same bar size and span | Architectural screens, lightweight walkways, marine access |
| FRP (fibre-reinforced plastic) | Chemically resistant, and non-conductive in suitable resin systems; moulded and pultruded versions differ in strength and open area; lower stiffness than steel | Water and wastewater treatment, chemical plants, electrical areas |
For bar gratings in mild steel, Indian manufacturers typically specify IS 2062 structural steel, the standard for hot-rolled medium and high tensile structural steel.
Plain grating has a smooth top edge on every bearing bar and suits dry indoor areas. Serrated grating has notches cut into the top edge of the bearing bars to improve grip where oil, water or ice make surfaces slippery. BS 4592-1 sets minimum dimensions for serrations on industrial open bar gratings. Serration is a surface option rather than a standard feature, so confirm availability with the supplier before specifying it.
Serrations remove steel from the top of the bar, so a serrated bar carries less load than a plain bar of the same size. Check load data for the serrated section rather than the plain one.
A stair tread grating is a grating panel cut to tread size, with end plates for bolting to the stair stringers and a nosing along the front edge. Industrial and outdoor stairs use it because water drains through and the open surface stays grippy. Aparna Rollform manufactures step gratings for stairways; the specification table below lists the sizes, materials and finishes on offer.
Heavy-duty grating uses deeper and thicker bearing bars so it can carry vehicle wheels, forklifts and trolleys rather than just foot traffic. Loading docks, plant roads and trench crossings use it. NAAMM publishes a separate manual for heavy-duty grating (MBG 532).
“Heavy-duty” is an industry duty classification, not a product name. A supplier can only call a panel heavy-duty if published load tables support the wheel loads in question, so always ask for that data.
Plank grating starts as a single metal sheet. A press forms it into a channel and punches raised, perforated or serrated openings into the top face. Plank grating is commonly used for pedestrian and light-duty applications; load capacity should be confirmed from the product load data.
Expanded metal grating starts as a sheet that a machine slits and stretches into diamond-shaped openings. It is formed from a single expanded sheet without welded bar intersections. Neither type contains bearing bars, which is why engineers treat them as alternatives to bar grating rather than as bar grating types.
| Type | Construction | Panel character | Custom shapes | Common uses |
|---|---|---|---|---|
| Manual welded | Hand-welded at each intersection | Rigid; finish depends on fabricator | Very flexible | Custom platforms, circular panels, panels with cut-outs, small batches |
| Electroforged | Machine resistance-welded under pressure | Rigid and uniform | Needs post-forging cutting and banding | Standard walkways, platforms, trench covers |
| Pressure-locked | Cross bars pressed into notched bearing bars | Flush, neat pattern; close spacing possible | Moderate | Façades, ceilings, fencing, pedestrian areas |
| Swage-locked | Tubular cross bars swaged through bearing bars | Light; mostly aluminium | Moderate | Lightweight walkways, architectural use |
| Riveted | Bent connecting bars riveted to bearing bars | Zig-zag pattern | Limited | Areas with repeated rolling loads |
| Plank | Formed and punched sheet | Very grippy surface | Limited | Roof walkways, catwalks |
| Expanded metal | Slit and stretched sheet | One piece, diamond openings | Easy to cut | Light walkways, guards, screens |
This table compares construction and use, not load capacity. Capacity depends on bar size, pitch, span, material and support conditions, so always confirm it from the manufacturer’s load data.
In a steel structure, grating forms the walking surface of platforms, walkways, catwalks, mezzanines, pipe racks, conveyor galleries and stair landings. It rests on the steel beams of the frame, transfers loads to them, and lets light, air and spilled liquids pass through to the level below.
Four details decide whether a grating works in the structure:
In building construction more broadly, gratings also cover drainage trenches, service pits and basement ventilation shafts, and provide stair treads for fire escapes and utility stairs.
Mild steel grating needs protection in almost every environment. The two common finishes are:
Stainless steel, aluminium and FRP gratings normally go into service without an added coating.
Work through these questions in order. Each one narrows the choice of construction, material and surface.
Selection guidance helps you shortlist a grating type. It does not replace design. A qualified structural engineer should confirm bar size, pitch, span and fixing against the actual loads, using the manufacturer’s load tables and the applicable design standards for the project.
Chequered plate is a solid steel plate with a raised pattern. Grating is an open grid. Choose grating where liquids must drain, light and air must pass, or dust and debris must not collect. Choose chequered plate where nothing should fall through, such as floors above electrical equipment or areas that need a continuous sealed surface. Across the industry, many stair treads combine both, with a chequered plate nosing on a grating tread. Nosing options vary by supplier, so confirm what is available before specifying.
Aparna Rollform manufactures manual welded gratings and step gratings at its plant in Patancheru, Telangana. The current range covers:
| Parameter | Range |
|---|---|
| Width | 250 to 1,400 mm |
| Span (length) | 500 to 3,000 mm |
| Bearing bars | 25 × 5, 25 × 6, 32 × 5 and 32 × 6 mm; other sizes to order |
| Cross bars | Square bar, 6, 8, 9 and 10–12 mm |
| Mild steel | IS 2062, IS 1079 and IS 10748 |
| Stainless steel | Grade 304 & 316 |
| Finishes | Hot-dip galvanised; red oxide |
Explore Aparna Rollform’s grating range, or share your drawings or requirements for product and specification enquiries.
By construction, the main types of grating include welded (manual or electroforged), pressure-locked, swage-locked and riveted grating. By material, gratings come in mild steel, stainless steel, aluminium and FRP. By surface and form, plain and serrated describe the surface, stair tread and heavy-duty describe form and duty, and plank and expanded metal are sheet-based alternatives to bar grating. Welded mild steel grating is commonly used in industrial applications.
In a steel structure, grating is the open-grid flooring panel that forms platforms, walkways, catwalks, mezzanines and stair landings. It sits on the structural beams with its bearing bars spanning between supports, and clips or welds fix it in place. It carries foot or equipment loads while letting light, air and liquids pass through.
Electroforged grating is a type of welded grating. A machine fuses the cross bars into the bearing bars using electric current and hydraulic pressure, producing uniform standard panels. Manual welded grating relies on a welder joining each intersection, which suits custom shapes, cut-outs and small batches.
Most steel grating uses mild (carbon) steel, commonly to IS 2062 in India, finished with hot-dip galvanising or paint. Stainless steel 304 or 316 suits corrosive, hygienic or coastal areas. Aluminium is the alternative where low weight matters more than stiffness, although it conducts electricity. FRP suits chemically aggressive areas and, in suitable resin systems, areas that need a non-conductive floor.
Serrated grating has notched bearing bars that improve grip on surfaces exposed to oil, water or ice, such as outdoor stairs, loading areas and process plant platforms. The notches reduce the effective depth of each bar, so check load data for the serrated section before specifying it.
Grating is an open grid that drains liquids and lets light and air through. Chequered plate is a solid, patterned steel plate that stops anything falling through. Use grating for drainage, ventilation and debris-free walkways, and chequered plate where the chequered plate where a continuous solid surface is required.
Disclaimer: The information in this article is provided for general informational purposes. Grating types, materials, finishes, standards and applications may vary depending on project requirements and supplier specifications. Aparna Rollform product specifications, sizes, materials, finishes and availability should be confirmed with the technical team before final selection or use.
Aparna Rollform is a cable tray manufacturer in India, producing perforated, ladder, solid-bottom and raceway cable trays in galvanised and powder-coated finishes. Explore the range or request a quote.
Aparna Rollform is a cable tray manufacturer in India, producing perforated, ladder, solid-bottom and raceway cable trays in galvanised and powder-coated finishes. Explore the range or request a quote.
Aparna Rollform is a cable tray manufacturer in India, producing perforated, ladder, solid-bottom and raceway cable trays in galvanised and powder-coated finishes. Explore the range or request a quote.
