Is Fiberglass Grating Better Than Steel Grating?

The short version: fiberglass grating costs more to buy, weighs a fraction as much, does not rust and does not conduct electricity, but its resin limits its service temperature. Steel grating is cheaper up front and is not limited by a resin, but galvanized steel needs repainting, which one maker’s 2026 comparison puts at every 5–7 years.

Strength belongs to a product, its depth and its span, not to a material name, so compare the published load tables of the two products you are choosing between. Read fiberglass tables against a deflection limit such as 3/8" (9.5 mm) or L/120 for comfort, and remember makers’ safe loads rest on safety factors from 2:1 to 5:1.

For wheel loads, US suppliers rate heavy-duty FRP grating up to AASHTO H-20. Strongrate’s catalog gives spans under truck, car and forklift wheel loads only for its HI high-load pultruded grating, and any wheel-load use needs your engineer’s review. Strongrate values come from its 2023 catalog and are confirmed in your quote and submittal drawings before design use; see fiberglass grating load tables.

Galvanized steel starts cheaper: one maker’s September 2026 comparison says it is often quoted 20–40% below an equivalent FRP panel, and FRP price guides put it at one third to one half the cost per sq ft. The same comparison repaints steel every 5–7 years over a 20-year horizon, which means 2 or 3 repaints (years 7 and 14, or years 5, 10 and 15).

How to read the worksheet: if one repaint of the steel grating costs more than about 7–20% of the fiberglass material price (the maker comparison) or about 17–33% (the price guides), fiberglass is cheaper over 20 years. Lighter panels and no repaint downtime favor fiberglass further; discounting future repaints favors steel.

Compare imported fiberglass at its delivered price, with US duty and freight added: see fiberglass grating price and landed cost, duty and freight.

• First cost decides and the area is dry. Galvanized steel is often quoted 20–40% below an equivalent FRP panel. Where your plant expects few repaints, the 20-year worksheet above can favor steel.
• Heat beyond the resin. Published service limits run about 150–160°F (66–71°C) for polyester, 185–200°F (85–93°C) for vinyl ester and up to 300°F (149°C) for phenolic. Above the limit of the resin you can get, use metal grating.
• Federally funded infrastructure. China-made FRP grating, Strongrate’s included, does not qualify for projects covered by Build America, Buy America; such projects need US-made products, and on EPA State Revolving Fund projects steel grating falls under the American Iron and Steel requirement. See Buy America (BABA).
• Vehicle or forklift traffic, if you want Strongrate. Strongrate’s catalog gives spans under truck, car and forklift wheel loads only for its HI high-load pultruded grating, and any wheel-load use needs your engineer’s review. US suppliers rate heavy-duty FRP grating up to AASHTO H-20, so compare a rated product against steel.

Fiberglass earns its higher price where steel would corrode, conduct or be too heavy to handle. As one US supplier publishes it, a typical 4 ft × 12 ft (1220 × 3660 mm) molded panel weighs about 120 lb (54.4 kg) at 1" (25 mm) depth and 180 lb (81.6 kg) at 1-1/2" (38 mm), and it needs no repainting against rust. Outdoors, US guide specifications require a UV inhibitor in FRP exposed to weather.

• Wet and corrosive areas: chemical plants, washdown floors, car washes, docks and marinas, and trench covers and drain grates. Pick the resin for the chemicals: vinyl ester for harsher service.
• Electrical areas: fiberglass grating is non-conductive and is marketed for electrical flooring.
• Weight-limited structures and hand installation: US makers describe fiberglass as up to 70–75% lighter than steel grating.
• Long service without coating upkeep: in one maker’s study, 30-year-old pultruded grating kept about 85% of its flexural modulus.
• Fire-rated walkways: the six Strongrate models on its DNV certificate have ASTM E84-19a flame spread indexes of 5–20, within the 25-or-less limit in US guide specifications; see ASTM E84 Class 1 fire rating.

Those E84 results apply only to the six models on DNV Type Approval TAF0000191 Rev. 1, and that approval is a fire-technical evaluation, not a structural one.

Strongrate makes molded and pultruded fiberglass grating in Nantong, China, and ships from China. Its catalog lists 1-1/2" square-mesh molded grating at 2.5 lb/ft² (12.3 kg/m²) for 1" (25 mm) deep and 4.0 lb/ft² (19.5 kg/m²) for 1-1/2" (38 mm) deep. Before swapping steel for fiberglass on existing framing, check the support spacing against the fiberglass load table at your design load and deflection limit, then fix the panels with hold-down clips; see how to install fiberglass grating, fiberglass grating sizes and weights and fiberglass grating clips.

Full containers and project quantities are quoted factory-direct; orders under about 500 sq ft, or needed in under 3 weeks, are referred to a US stocking importer.