Steel Grating Sizes and Mesh Spacing Guide

How steel grating size is described

Buyers often ask for a “standard grating size,” but several dimensions are involved. A complete callout identifies the bearing-bar profile, bearing-bar spacing, cross-bar spacing, construction, surface, material, finish and overall panel size.

Bearing-bar depth and thickness

The bearing bars are the main spanning members. A designation such as 30 × 3 mm describes a rectangular bar 30 mm deep and 3 mm thick. Other depths and thicknesses are selected from the clear span, distributed load, concentrated load and deflection limit. Confirm the selection against project-specific load tables.

What does 30 × 100 mm mesh mean?

It normally indicates approximately 30 mm bearing-bar pitch and 100 mm cross-bar pitch, measured center to center. The mesh alone is not a complete product specification because 25 × 3, 30 × 3 and 40 × 5 mm bearing bars could all use similar spacing while carrying different loads.

30 × 50 mm and closer cross-bar spacing

A 30 × 50 mm arrangement keeps the same nominal bearing-bar pitch but places cross bars more closely. It may be used where the applicable project specification, surface feel, opening pattern or local practice calls for it. It does not automatically double the load capacity because primary capacity is governed mainly by bearing bars and span.

What does 19-W-4 mean?

In a common North American welded-grating designation, 19 means bearing bars at 19/16 inch on center, W means welded construction, and 4 means cross bars at 4 inches on center. A full callout still needs the bearing-bar size, such as 1-1/4 × 3/16 inch.

Close-mesh and ball-proof grating

Close-mesh products reduce the clear openings. They may be specified for public access, small-wheel traffic or dropped-object control. “Ball-proof” must state the required test sphere and governing specification; the phrase alone is not precise enough for procurement.

Panel length, width and bearing-bar direction

Panel size is the finished outside dimension. Length is commonly taken in the bearing-bar direction, while width runs across the bearing bars. Drawings should include a bearing-bar arrow because naming conventions can differ between suppliers and projects.

Panels may be stock sizes or fabricated to suit support lines, openings, transport and handling. Do not select a large panel only to reduce joints; it must still be practical to finish, ship, lift and install.

Steel grating size specification example

A useful metric callout might read: welded steel grating, rectangular bearing bars 30 × 3 mm at 30 mm pitch, cross bars at 100 mm pitch, plain surface, hot-dip galvanized after fabrication, panel dimensions and piece marks per approved layout.

Selection checklist

• Clear span, bearing direction and support width.
• Uniform and concentrated loads with deflection limit.
• Bearing-bar depth, thickness and pitch.
• Cross-bar type and pitch.
• Pedestrian, wheel, drainage and dropped-object requirements.
• Panel size, banding, cut-outs, finish and fixings.

Frequently asked questions

Is mesh size the same as panel size?

No. Mesh describes bar spacing. Panel size is the complete fabricated length and width.

Is 30 × 100 mm mesh equivalent to 19-W-4?

They are close in general layout but come from different designation systems. Do not treat them as automatically interchangeable; confirm the exact pitch, bar size and governing standard.

What size should I request?

Send the support span, loads, use, opening requirements and finish. Request a size review before fixing the purchase specification.