Moulded vs pultruded FRP grating: how to choose

Construction

	Moulded grating	Pultruded grating
How it is made	Glass roving laid in a mould and wetted with resin, cured as one piece	Continuous-fibre bars pulled through a die, then joined with cross rods
Typical pattern	Square mesh, e.g. 38 × 38 mm	Parallel I- or T-bars with cross rods
Load direction	Two-way	One-way (along the bearing bars)
Glass content	Lower, resin-rich	Higher

Performance differences

• Span and stiffness. Pultruded bars have far higher stiffness along their length, so they reach longer spans or heavier loads at the same depth. Moulded grating is limited by deflection at longer spans.
• Corrosion resistance. Moulded grating’s resin-rich construction gives excellent chemical resistance; pultruded grating is also corrosion resistant, and resin choice (isophthalic vs vinyl ester) matters for both.
• Cutting and openings. Moulded grating can be cut in any direction without losing its two-way structure; pultruded panels must keep enough cross rods near cuts.
• Impact. Moulded grating’s bi-directional mesh distributes point impacts well.

Rule of thumb

Choose moulded for platforms and walkways with normal support spacing, frequent cut-outs and chemical exposure. Choose pultruded when support spacing is wide, loads are higher, or you want to reduce the number of support beams.

Always check the load table

Both types are specified from the manufacturer’s load/deflection tables for your span and load case. Ask for the tables of the exact series quoted — values differ between manufacturers.