KEY TAKEAWAYS
- GI gratings are galvanised steel mesh panels used for industrial walkways, stair treads, mezzanine floors, and load platforms
- The hot-dip galvanising process bonds zinc directly to the steel surface, giving it corrosion resistance that painted finishes cannot match over time
- Load ratings depend on bar height, bar thickness, and pitch spacing – under-specifying leads to deflection and weld fatigue
- The open mesh allows light, airflow, and sprinkler water to pass through – a fire safety requirement for mezzanine floors in most markets
- For UAE facilities, galvanised finish outperforms powder coat in semi-outdoor and high-humidity environments
Many buyers specify GI gratings once and assume the job is done. It is not.
GI gratings are galvanised steel mesh panels installed as walkway surfaces, stair treads, mezzanine floors, and platform decking in warehouses and industrial facilities worldwide. The open steel mesh handles foot traffic and light equipment loads while allowing drainage, airflow, and light to pass through.
Standard load ratings run from 2.5 to 5 kN/m² depending on bar height and pitch. Selecting the right configuration for each application is what determines long-term performance.
Specification errors do not show up immediately. They show up under load.
This guide covers the key features of GI gratings, the three main types, and the specification factors that determine how long an installation holds up.
What GI Grating Actually Is
GI stands for galvanised iron – a reference to the surface treatment applied during manufacture, not a separate metal.
The base material is structural steel, formed into flat bars and cross rods, welded at every intersection to create the mesh panel. Hot-dip galvanising bonds a zinc layer to the steel through a metallurgical reaction – not a coating applied on top, but zinc fused into the steel itself.
A painted or powder-coated surface cracks over time, allowing moisture to reach the bare steel beneath. A galvanised surface sacrifices the zinc layer first, protecting the steel even as the surface wears.
That distinction makes finish type a structural decision.
Understanding the galvanising process is what determines which type of grating to select – and why.
The Three Main Types of GI Grating
The three types used in warehouse and industrial settings each suit a different load condition. Selecting the wrong one produces a surface that passes inspection and fails in practice.
Press-locked grating is manufactured by pressing cross bars through pre-punched slots in the bearing bars under hydraulic pressure, creating a mechanical lock at every intersection. It is the standard choice for heavy foot traffic, plant room walkways, and industrial stair treads.
Welded grating uses resistance welding to join bearing bars and cross rods at every intersection. It is available in the widest range of bar sizes and is the most common type for mezzanine floors and general warehouse walkways.
Swaged grating interlocks bars through a mechanical deformation process without welding. It is lighter than the other two types and suited for equipment access panels, trench covers, and platform decking where weight matters more than rigidity.
Not suited for sustained foot traffic.
Which type is correct depends on span and live load. We advise on the right configuration for every mezzanine and walkway project we supply.
Load Ratings and How to Specify Correctly
Three variables determine a GI grating panel’s load rating: bearing bar height, bearing bar thickness, and pitch – the centre-to-centre spacing between bearing bars.
Standard warehouse walkways and mezzanine floors are specified at a minimum of 2.5 kN/m², covering two adults plus a loaded hand trolley on any given square metre. Heavier applications – plant room walkways, pallet truck areas, or platforms above machinery – are specified at 5.0 kN/m² or above.
The span between support beams matters as much as the load rating. A panel rated at 5.0 kN/m² over 600 mm may deflect unacceptably over 1,000 mm under the same load.
Load tables from reputable manufacturers show the maximum permissible span for each bar configuration at each load rating. Always ask for that table.
If a supplier cannot provide it, walk away.
Need GI grating for a warehouse or mezzanine project? View our GI grating range – we supply press-locked, welded, and swaged configurations with full load data for industrial applications across the UAE.
Load rating covers structural performance. Surface finish determines how long that performance holds.
Surface Finish and Anti-Slip Options
Hot-dip galvanising is the standard finish for industrial GI gratings, and the finish specification matters as much as the structural one.
The zinc coating typically runs 45-85 microns thick, providing 20-40 years of corrosion protection in dry indoor environments. In wet or outdoor conditions, that drops to 10-20 years depending on exposure.
Both ranges substantially exceed painted alternatives.
Serrated bar edges are applied to the top face of bearing bars to increase grip. They are specified for stair treads, wet areas, and surfaces where smooth galvanised steel provides insufficient slip resistance.
Serration does not affect the load rating.
Epoxy grit coatings are a third option for food processing areas or facilities with specific safety certification requirements. For standard warehouse and industrial use, serrated hot-dip galvanised grating covers the requirement.
With structural specification and finish confirmed, the final factor is placement – where in the facility each configuration belongs.
Where GI Gratings Are Used in Warehouses and Industrial Facilities
GI gratings appear in five main locations across warehouse and factory environments. Each carries a different load and span requirement.
Mezzanine floors are the most common application. The open mesh satisfies fire safety codes requiring sprinkler water to reach the floor below, and handles distributed loads from warehoused goods and pick operations.
We supply GI gratings for both steel mezzanine floors and rack supported mezzanine floors. The specification differs for each type.
Stair treads use serrated grating on steps where oil, dust, or water creates a slip risk on solid surfaces. We fabricate and install staircases using serrated GI grating as the standard tread surface.
Elevated walkways above machinery use GI grating as the deck surface on structural steel frames. The open mesh prevents heat and gas buildup – a problem solid steel decking creates.
Platform decking around tanks and processing equipment uses the same open structure to drain spills downward. Trench and drain covers close open channels while remaining removable for inspection and cleaning.
We advise on the correct panel for each zone as part of every project we supply. For a full view of our storage and fabrication solutions, see our complete range.
Frequently Asked Questions
What does GI stand for in GI grating?
GI stands for galvanised iron – a reference to the surface treatment applied to steel during manufacture. The process bonds zinc to the steel through a metallurgical reaction, creating corrosion resistance that holds even after surface abrasion.
How long does GI grating last in a warehouse environment?
Hot-dip galvanised grating in a dry indoor warehouse typically lasts 20-40 years. In wet or outdoor conditions, that range drops to 10-20 years. When red rust appears, the zinc has been consumed and the panel should be inspected for replacement.
What is the difference between GI grating and GI wire mesh decking?
GI wire mesh decking is a lighter-gauge racking accessory designed for placement on racking beams as a shelf surface – it is not rated for foot traffic. GI grating is a structural flooring product tested for walkways, stair treads, and mezzanine floors. The two are not interchangeable.
Can GI grating be cut to size on site?
Yes – GI grating can be cut with an angle grinder or cold saw to fit non-standard dimensions. Cut edges should be treated with cold galvanising compound to restore corrosion protection where the zinc coating has been removed.
Is GI grating suitable for outdoor areas in UAE warehouse facilities?
Yes – hot-dip galvanised grating is the correct specification for outdoor and semi-outdoor areas in the UAE. Powder coat in outdoor conditions typically shows cracking and delamination within 3-5 years, while galvanised steel holds up substantially longer. For marine environments, duplex coating – galvanising plus powder coat – is recommended