--- title: "Molded Fiberglass Grating (FRP): Sizes, Specs · Strongrate" description: "Molded fiberglass grating (molded FRP grating) by depth and mesh: four DNV-listed models, panel sizes, resins and surfaces. Made in Nantong, China." url: https://www.strongrate.us/molded-fiberglass-grating/ markdown: https://www.strongrate.us/molded-fiberglass-grating.md published: 2026-10-16 updated: 2026-10-17 --- [Home](https://www.strongrate.us/) › [Fiberglass grating](https://www.strongrate.us/fiberglass-grating/) › [Molded grating](https://www.strongrate.us/molded-fiberglass-grating/) # Molded Fiberglass Grating _Updated Oct 17, 2026_ Molded fiberglass grating is cast as one piece with strength in both directions. Strongrate's catalog lists square, rectangular and mini meshes from 1/2" (13 mm) to 2-9/16" (65 mm) deep, with 30–35% glass. Four of its molded models are on DNV Type Approval TAF0000191 Rev. 1, with ASTM E84-19a flame spread indexes of 5 to 15. Choose the depth by span and load, then the mesh. _Diagram: Molded square-mesh grating, plan and section. Schematic — not to scale._ ## Which mesh and depth fit your project? Start with the load and the clear span between supports, which set the depth; each product page has the catalog load tables. Then choose the mesh: square mesh for general flooring and walkways, rectangular mesh to match existing 1" × 4" grating or for the DNV-listed vinyl ester model, and mini mesh for accessible routes or where small items must not drop through. **Molded fiberglass grating by mesh and depth: Strongrate catalog values and DNV fire results** | Configuration | Depth | Mesh | Weight (catalog) | Open area (catalog) | DNV-listed model and resin | ASTM E84 flame spread index | | --- | --- | --- | ---: | ---: | --- | ---: | | [1" square mesh](https://www.strongrate.us/molded-fiberglass-grating/1-inch-square-mesh/) | 1" (25 mm) [note 1] | 1-1/2" × 1-1/2" (38 × 38 mm) | 2.5 lb/ft² (12.3 kg/m²) [note 2] | 68% [note 2] | 38×38×25 mm, isophthalic polyester [note 1] | 10 [note 3] | | 1-1/4" square mesh, fire-retardant | 1-1/4" (32 mm) [note 1] | 1-1/2" × 1-1/2" (38 × 38 mm) | — | — | 38×38×32 mm, fire-retardant orthophthalic polyester [note 1] | 5 [note 3] | | [1-1/2" square mesh](https://www.strongrate.us/molded-fiberglass-grating/1-5-inch-square-mesh/) | 1-1/2" (38 mm) [note 1] | 1-1/2" × 1-1/2" (38 × 38 mm) | 4.0 lb/ft² (19.5 kg/m²) [note 2] | 68% [note 2] | 38×38×38 mm, isophthalic polyester [note 1] | 15 [note 3] | | [2" square mesh](https://www.strongrate.us/molded-fiberglass-grating/2-inch-square-mesh/) | 2" (50 mm) [note 2] | 2" × 2" (51 × 51 mm) | 4.4–4.8 lb/ft² (21.5–23.5 kg/m²) [note 2] | 78% [note 2] | Not listed | — | | [1" × 4" rectangular mesh, standard and heavy duty](https://www.strongrate.us/molded-fiberglass-grating/1x4-rectangular-mesh/) | 1" (25 mm) [note 2] | 1" × 4" (25 × 102 mm) | 2.7–3.2 lb/ft² (13.0–15.6 kg/m²) [note 2] | 67% [note 2] | Not listed | — | | [1" × 6" rectangular mesh](https://www.strongrate.us/molded-fiberglass-grating/1x4-rectangular-mesh/) | 1-1/2" (38 mm) [note 1] | 1" × 6" (25 × 152 mm) | 4.6 lb/ft² (22.5 kg/m²) [note 2] | 63% [note 2] | 25.4×152.4×38 mm, vinyl ester [note 1] | 10 [note 4] | | [Mini mesh (micro-mesh), five patterns](https://www.strongrate.us/molded-fiberglass-grating/mini-mesh-ada/) | 9/16" (14 mm) to 2-3/8" (60 mm) [note 2] | 3/4" × 3/4" openings on 1-1/2" × 1-1/2" centers (19 × 19 / 38 × 38 mm) and four other patterns [note 2] | 3.4 lb/ft² (16.8 kg/m²) [note 2] | 30% [note 2] | Not listed | — | _Weights and open areas as printed in Strongrate’s 2023 catalog; weight and open area in the mini-mesh row are for the first catalog row of its 3/4" pattern. Fire results are from DNV Type Approval TAF0000191 Rev. 1 and apply to the listed model and resin only; more on the test: [ASTM E84 Class 1 fire rating](https://www.strongrate.us/resources/astm-e84-class-1-fire-rating/)._ Notes: 1. Inch sizes are North American nominals of the metric certificate designation. 2. Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings. 3. Result as listed on DNV certificate TAF0000191 Rev. 1 (ASTM E84-19a); applies to this model only. 4. Result as listed on DNV certificate TAF0000191 Rev. 1 (ASTM E84-19a); applies to the 1" × 6" model only, not to a 1" × 4" product. - Fire data on the certificate applies to these six models only. The catalog also lists heavy-duty (HD) versions of the 1-1/2" square mesh at 2" (50 mm), 2-3/8" (60 mm), 2-9/16" (65 mm) deep, other rectangular meshes and metric meshes; name them in your quote request. Every product's sizes and weights are compared on [fiberglass grating sizes, weight and open area](https://www.strongrate.us/resources/fiberglass-grating-sizes-weight-and-open-area/), and span tables explained on [fiberglass grating load tables](https://www.strongrate.us/resources/fiberglass-grating-load-tables/). - [1" molded grating, 1-1/2" square mesh](https://www.strongrate.us/molded-fiberglass-grating/1-inch-square-mesh/): DNV-listed model 38×38×25 mm, isophthalic. Catalog: 2.5 lb/ft² (12.3 kg/m²), 68% open, with load tables. (DNV-listed) - [1-1/2" molded grating, 1-1/2" square mesh](https://www.strongrate.us/molded-fiberglass-grating/1-5-inch-square-mesh/): DNV-listed model 38×38×38 mm, isophthalic. Catalog: 4.0 lb/ft² (19.5 kg/m²), 68% open, with load tables. (DNV-listed) - [2" molded grating, 2" square mesh](https://www.strongrate.us/molded-fiberglass-grating/2-inch-square-mesh/): For loads and spans beyond 1-1/2" grating. Catalog: 4.4–4.8 lb/ft² (21.5–23.5 kg/m²), 78% open, with load tables. (In the catalog) - [Rectangular mesh fiberglass grating (1" × 4", 1" × 6")](https://www.strongrate.us/molded-fiberglass-grating/1x4-rectangular-mesh/): 1" × 4" mesh 1" deep, standard and heavy duty, and the DNV-listed 1" × 6" mesh 1-1/2" deep in vinyl ester, with load tables. (DNV-listed (1" × 6")) - [Mini mesh fiberglass grating](https://www.strongrate.us/molded-fiberglass-grating/mini-mesh-ada/): Five catalog patterns for accessible routes and areas where parts must not drop through, with the ADA opening rule explained. (In the catalog) ## What panel sizes does molded grating come in? Most of Strongrate's inch meshes are printed in 4 ft × 12 ft (1220 × 3660 mm), 4 ft × 8 ft (1220 × 2440 mm) and 3 ft × 10 ft (921 × 3050 mm), close to the common US sizes, and many also in 5 ft × 13.12 ft (1524 × 4000 mm). Each product page lists its sizes. On site, molded grating is cut with carbide or diamond tooling and the cut edges sealed with resin; see [how to cut fiberglass grating](https://www.strongrate.us/resources/how-to-cut-fiberglass-grating/) and [how to install fiberglass grating](https://www.strongrate.us/resources/how-to-install-fiberglass-grating/). ## Which resin should you choose for molded grating? Match the resin to the chemicals and temperature on site. Strongrate's catalog lists four fire-retardant resin systems for molded grating, and three of them are on its DNV certificate: isophthalic polyester, vinyl ester and fire-retardant orthophthalic polyester. The catalog's chemical-resistance chart is on [fiberglass grating specifications](https://www.strongrate.us/resources/fiberglass-grating-specifications/). **Strongrate resin systems: catalog data** | Code | Resin | Use | Corrosion resistance | Products | Max temperature | | --- | --- | --- | --- | --- | ---: | | VEFR [note 1] | Vinyl ester | Superior corrosion resistance, fire retardant | Excellent | Molded and pultruded | 230°F (110°C) [note 1] | | IFR [note 1] | Isophthalic polyester | Industrial-grade corrosion resistance, fire retardant | Very good | Molded and pultruded | 176°F (80°C) [note 1] | | FG [note 1] | Isophthalic polyester, food grade | Food-grade corrosion resistance, fire retardant | Very good | Molded and pultruded | 176°F (80°C) [note 1] | | OFR [note 1] | Orthophthalic polyester | Moderate corrosion resistance, fire retardant | Moderate | Molded only | 158°F (70°C) [note 1] | _As printed in Strongrate’s 2023 product catalog; confirmed in your quote and submittal drawings. The catalog rates every resin system ASTM E84 Class 1 (flame spread 25 or less); test results on file cover only the DNV-listed models. Its chemical-resistance chart prints lower maximum temperatures (vinyl ester 185°F (85°C), isophthalic 158°F (70°C), general-purpose polyester 149°F (65°C))._ Notes: 1. Maximum service temperatures as printed in the catalog’s resin table. - General information from resin makers’ data, as printed in the catalog; testing in the actual environment is recommended. ## Which surfaces and special types are listed? - **Concave (meniscus) top:** the standard molded surface. - **Gritted top:** slip coefficient 0.91 (ASTM D2047) for the normal grit surface, per the catalog. - **Solid cover** with a checker or grit finish, for trench covers and solid walkways; see [trench covers and drain grates](https://www.strongrate.us/applications/trench-covers-and-drain-grates/). - **Conductive grating**, 1 × 10⁵ to 5 × 10⁵ ohms, for spark-sensitive plants. - **Transparent grating**, pure resin with little or no pigment. Need longer spans or higher stiffness than molded grating gives? Compare [molded vs pultruded fiberglass grating](https://www.strongrate.us/compare/molded-vs-pultruded-fiberglass-grating/) and [pultruded fiberglass grating](https://www.strongrate.us/pultruded-fiberglass-grating/). ## How is molded grating quoted and shipped? Made in Nantong, China, and shipped from China. Full containers and project quantities are quoted factory-direct; orders under about 500 sq ft, or needed in under 3 weeks, are referred to US stocking importers. Prices are quoted per project: see [fiberglass grating price per square foot](https://www.strongrate.us/pricing/fiberglass-grating-price/), [lead times, MOQ and shipping](https://www.strongrate.us/buy-direct/lead-times-moq-and-shipping/) and [request a quote](https://www.strongrate.us/request-quote/). ## Frequently asked questions ### Will Strongrate molded panels fit frames made for another maker’s panels? Check before ordering: Strongrate’s catalog sizes are metric (for example 4 ft × 12 ft (1220 × 3660 mm)). One US maker’s guide specification holds molded grating to within 1/16" (1.6 mm) either way on depth and mesh. Send the frame’s clear opening, the depth and the mesh with your [quote request](https://www.strongrate.us/request-quote/) so the fit can be confirmed. ### Is there a 1-1/4" deep Strongrate molded grating? The DNV certificate lists one: model 38×38×32 mm, read as a 1-1/2" square mesh 1-1/4" (32 mm) deep, in fire-retardant orthophthalic polyester, with an ASTM E84-19a flame spread index of 5. The 2023 catalog does not print a 32 mm depth for that mesh, so ask for it by model in your quote request. ## Related pages - [Fiberglass grating](https://www.strongrate.us/fiberglass-grating/): What fiberglass (FRP) grating is, how molded and pultruded types differ, standard panel sizes and price ranges, and the grating options Strongrate makes. - [Pultruded fiberglass grating](https://www.strongrate.us/pultruded-fiberglass-grating/): Strongrate pultruded fiberglass (FRP) grating: the 36 I-bar and T-bar types in the factory catalog with depth, open area and weight, the two DNV-listed models and their ASTM E84 results, resins, surfaces and how to order. - [Molded vs pultruded grating](https://www.strongrate.us/compare/molded-vs-pultruded-fiberglass-grating/): How molded and pultruded fiberglass grating differ in manufacture, glass content, stiffness, weight, open area and cost, with a decision table by application. - [Fiberglass grating load tables](https://www.strongrate.us/resources/fiberglass-grating-load-tables/): The load tables in Strongrate’s catalog for each product, and how to read fiberglass grating load tables: uniform and line loads by span, deflection limits and safety factors. - [Fiberglass grating sizes, weight and open area](https://www.strongrate.us/resources/fiberglass-grating-sizes-weight-and-open-area/): Strongrate’s catalog size tables for molded and pultruded fiberglass grating (depth, weight, open area, panel sizes), common US panel sizes, and how to work out panel weight. **Request a quote:** https://www.strongrate.us/request-quote/ · Order a sample: https://www.strongrate.us/samples/ — Quote this configuration: send mesh, depth, resin, surface, panel size, quantity and ZIP code. Quotes within 1 business day (US Central time). ## Sources - Strongrate product catalog “Your Best FRP Solution” (image PDF, Sep 2023), supplied by the site owner (accessed Oct 17, 2026) - [DNV Type Approval Certificate TAF0000191 Rev. 1, with ASTM E84-19a results and conditions (PDF on Strongrate’s ShipServ supplier profile)](https://www.shipserv.com/Shipserv/pages/profiles/261792/certifications/20241010142426209-DNV-GL-Certificate-GRATINGS-Strongrate.pdf) (accessed Oct 15, 2026) - [Fibergrate molded grating guide specification (Section 06610); Strongwell Section 06 74 13 molded grating specification](https://www.fibergrate.com/media/180193/fibergrate-frp-molded-grating-specs.pdf) (accessed Oct 15, 2026) - [Grating Pacific, Molded Fiberglass Grating Sizes (PDF)](https://gratingpacific.com/wp-content/uploads/2019/09/Molded-Fiberglass-Grating-Sizes.pdf) (accessed Oct 15, 2026) --- Fiberglass (FRP) grating made by NANTONG STRONGRATE CO.,LTD in Nantong, China. Products ship from China. Made in Nantong, China · Ships from China · HTS 3925.90.