Steel grating has long been the usual choice for industrial platforms. Composite grating, by contrast, is made by combining polyester resin and glass fibre in layers in a mould and curing them under heat and pressure. Both do the same job but behave differently under different conditions. In this article we compare them under concrete headings and explain which makes sense in which situation. Our aim is not to run either one down, but to put the right material in the right place.
Weight and installation
Composite grating is up to 70% lighter than steel grating. For example, 38×38 H38 moulded grating weighs approx. 18.5 kg/m² and 38×38 H30 approx. 14 kg/m². The lower weight shows in two places: transport costs fall, and panels can usually be carried and installed without a crane. Low weight also affects the supporting structure: a lighter floor places less dead load on it.
Panels can be cut on site with a circular saw and are fixed to the structure with M-type clips. This also makes it easier to replace old grating on an existing steel structure: as in the photo, steel supports and composite grating can be used together.
Corrosion, chemicals and maintenance
Composite grating does not rust and resists acids, alkalis and salt water. Galvanised steel has moderate corrosion resistance and ductile iron low resistance. This difference is decisive in treatment plants, the chemical and petrochemical industries, and in marinas, ports and shipyards. On steel, corrosion often starts at cut edges and welds; on composite, a cut edge contains no metal to rust.
Composite grating needs no painting or regular inspection; water and detergent are enough for cleaning. In chemical environments we select the resin system for each project; just tell us the substances present and the temperature.
Safety: electricity, slip resistance and theft
Composite is an electrical insulator and non-magnetic, which is why it is preferred in energy facilities, substations and rail systems; on maintenance walkways the grating itself does not conduct current. With a concave or gritted surface it offers an anti-slip floor and makes no metallic noise underfoot. As it has no scrap value, there is no risk of theft either; for channel covers in open areas this is no small detail. UV and impact resistance and bidirectional strength complete the list.
Fire performance calls for caution. We assess fire-retardant resin systems on request. Fire tests such as ASTM E84 and UL-94 classify how materials behave when exposed to flame; if your project requires a specific class, contact us for technical documents and certificates.
| Criterion | Composite grating | Steel grating |
|---|---|---|
| Weight | Up to 70% lighter | Heavier |
| Corrosion | Does not rust; acids, alkalis, salt water | Galvanised moderate, ductile iron low |
| Electricity | Insulating, non-magnetic | Conductive |
| Maintenance | No painting or regular inspection needed | Needs painting and inspection |
| Scrap value | None, no risk of theft | Yes |
| Installation | Usually no crane needed | Heavy panels may need a crane |
Which should you choose?
If the environment is dry, the corrosion risk low and the load very high, steel can remain a sensible option. If the environment is wet, saline or chemical, if electrical insulation is required, if you want to avoid shutdowns for maintenance or if you want to install without a crane, composite grating comes out ahead.
When deciding, look at the total cost, not just the material price. Add transport, crane, installation time, painting and maintenance. With composite there is no painting or regular inspection cost, and its low weight makes transport and installation easier; with steel, painting and inspection costs recur throughout its service life.
On the load side, the decision depends on the span. At a 600 mm span, 38×38 H50 carries a point load of approx. 3,325 kg; 38×38 H38 carries approx. 875 kg at the same span. Values are approximate and the final selection requires project engineering. Tell us your span and use, and we will compare the two materials together for your project.