Product
Molded and Pultruded Fiberglass Stair Treads
Updated
Strongrate's catalog lists molded fiberglass stair treads cut from 1-1/2" (38 mm) deep grating with a gritted, contrasting nosing, 9-1/4" to 11-5/16" (235–287 mm) wide, and pultruded grating treads with a gritted tube nosing. Use them for new or replacement stairs on steel stringers in wet, corrosive or outdoor areas. US guide specifications design treads for 100 psf (4.8 kPa) uniform or a 300 lb (1.3 kN) concentrated load.
Strongrate stair treads (catalog)
- Molded treads
- Cut from 1-1/2" (38 mm) deep grating: 1-1/2" × 1-1/2" (38 × 38 mm) square mesh, mini mesh or micro mesh, with a gritted nosing in a contrasting colorValues as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
- Standard tread widths
- 9-1/4" to 11-5/16" (235–287 mm)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.Front to back
- One-piece tread panels
- Molded-in double nosing: 10 ft × 22-1/4" (3050 × 565 mm) and 12 ft × 22-13/16" (3660 × 580 mm)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
- Pultruded treads
- Any catalog pultruded grating type, with a gritted square or rectangular tube nosing
- Resins
- Vinyl ester, isophthalic polyester and food-grade isophthalic on molded and pultruded grating; orthophthalic on molded onlyMaximum service temperatures as printed in the catalog’s resin table; its chemical-resistance chart prints lower maximums.
- UV resistance
- UV inhibitors in the molded grating resin
- Fastening
- STRONGFIX M (saddle) clip, which the catalog recommends for stair tread panelsThe catalog’s Chinese text also lists galvanized steel; the clip material is stated in your quote.
- Made in
- Nantong, Jiangsu, China; ships from China
| Mesh | Depth | Bar width (as printed) | Weight | Open area |
|---|---|---|---|---|
| 1-1/2" × 1-1/2" (38 × 38 mm)1 | 1-1/2" (38 mm)1 | 1/4" / 3/16" (7.0 / 5.0 mm)1 | 4.0 lb/ft² (19.5 kg/m²)1 | 68%1 |
| 3/4" × 3/4" openings on 1-1/2" × 1-1/2" centers (19 × 19 / 38 × 38 mm)1 | 1-1/2" (38 mm)1 | 1/4" / 3/16" (6.5 / 5.0 mm)1 | 4.8 lb/ft² (23.5 kg/m²)1 | 30%1 |
| 1" × 1" openings on 2-1/16" × 2-1/16" centers (26 × 26 / 52 × 52 mm)1 | 1-1/2" (38 mm)1 | 1/4" / 3/16" (6.5 / 5.0 mm)1 | 4.0 lb/ft² (19.5 kg/m²)1 | 60%1 |
Notes
- 1Values as printed in the factory catalog (2023).
What sizes do grating stair treads come in?
Molded treads are 1-1/2" (38 mm) deep and 9-1/4" to 11-5/16" (235–287 mm) front to back; one-piece panels with molded-in double nosing are 10 ft × 22-1/4" (3050 × 565 mm) and 12 ft × 22-13/16" (3660 × 580 mm). Treads are cut to length to fit between the stringers. OSHA 29 CFR 1910.25 asks for treads at least 9-1/2" (241 mm) deep on standard stairs, so check that the width you order meets it.
- Tread length: the clear distance between stringers, or the carrier-angle length if the treads sit on angles.
- Tread depth: front to back, so the finished stair meets the minimum for its stair type.
- Number of treads per flight and number of flights.
- Grating type and depth: molded or pultruded, and the depth your engineer has checked against the design load.
- Exposure: chemicals, temperature and outdoor sun, which decide the resin.
- Nosing color, the fastening detail, the delivery ZIP code and the need-by date.
What load must fiberglass stair treads carry?
OSHA 29 CFR 1910.25 requires stairs to support at least five times the normal anticipated live load, and never less than a 1,000 lb (4.4 kN) concentrated load. US guide specifications design the treads for 100 psf (4.8 kPa) uniform or a 300 lb (1.3 kN) concentrated load over 4 in² (2581 mm²). Your engineer checks the tread at your stringer spacing.
The catalog has no tread load table; the nearest data is the point-load table for the 1-1/2" (38 mm) deep, 1-1/2" × 1-1/2" (38 × 38 mm) square-mesh grating that molded treads are cut from. Ask for tread load data at your stringer spacing with your quote. How to read the columns: fiberglass grating load tables.
| Clear span | 331 lb (150 kg) | 772 lb (350 kg) | 1,102 lb (500 kg) | 1,653 lb (750 kg) | 2,205 lb (1,000 kg) | 3,307 lb (1,500 kg) | 5,512 lb (2,500 kg) | 6,614 lb (3,000 kg) |
|---|---|---|---|---|---|---|---|---|
| 11-13/16" (300 mm) | — | 0.01" (0.29 mm) | 0.02" (0.39 mm) | 0.03" (0.68 mm) | 0.04" (0.9 mm) | 0.05" (1.17 mm) | 0.07" (1.86 mm) | 0.09" (2.29 mm) |
| 17-3/4" (450 mm) | — | 0.02" (0.43 mm) | 0.02" (0.59 mm) | 0.04" (1.02 mm) | 0.05" (1.36 mm) | 0.07" (1.76 mm) | 0.11" (2.78 mm) | 0.14" (3.44 mm) |
| 23-5/8" (600 mm) | 0.02" (0.49 mm) | 0.04" (1.02 mm) | 0.05" (1.33 mm) | 0.08" (2.09 mm) | 0.12" (2.97 mm) | 0.16" (4.03 mm) | 0.26" (6.71 mm) | — |
| 29-1/2" (750 mm) | 0.03" (0.83 mm) | 0.08" (1.93 mm) | 0.10" (2.49 mm) | 0.16" (3.94 mm) | 0.23" (5.78 mm) | 0.31" (7.84 mm) | — | — |
| 35-7/16" (900 mm) | 0.05" (1.17 mm) | 0.11" (2.84 mm) | 0.14" (3.64 mm) | 0.23" (5.8 mm) | 0.34" (8.59 mm) | 0.46" (11.65 mm) | — | — |
| 47-1/4" (1200 mm) | 0.08" (1.94 mm) | 0.19" (4.88 mm) | 0.27" (6.83 mm) | 0.39" (9.91 mm) | 0.57" (14.56 mm) | — | — | — |
Notes
- Deflections as printed in the factory catalog (2023), static loads at ambient temperature.
- Catalog tables.
Which resins and surfaces are available?
Molded and pultruded treads come in the grating resins listed above: isophthalic polyester for general industrial use, vinyl ester for harsher chemical service. Molded treads carry a gritted nosing in a contrasting color. Resin choice by environment is covered on molded fiberglass grating and pultruded fiberglass grating.
Treads are fastened to the stringers or to carrier angles with saddle clips; see fiberglass grating clips. Cut on site with carbide or diamond tooling and seal the cut edges with resin: how to cut fiberglass grating. To resurface sound existing steps instead, see fiberglass stair tread covers.
How are stair treads quoted and shipped?
Made in Nantong, China, and shipped from China. New stairs across a plant and container orders are quoted factory-direct; a few replacement treads, orders under about 500 sq ft, or needs in under 3 weeks are referred to US stocking importers. Prices are quoted per project: see fiberglass grating price per square foot or request a quote.
Frequently asked questions
Do the DNV fire results apply to stair treads?
No. The ASTM E84 results on DNV Type Approval TAF0000191 Rev. 1 apply to six listed grating models only. Ask for fire data on the finished tread, nosing included, with your quote; see certifications and test reports.
How long do fiberglass stair treads last outdoors?
Strongwell’s guide specification requires FRP products exposed to weather to contain an ultraviolet inhibitor, and in Strongwell’s own study a 30-year-old pultruded grating kept about 85% of its flexural modulus. That is Strongwell data, not a Strongrate result; mention outdoor use in your quote request.
Can China-made fiberglass stair treads go on federally funded projects?
Not on projects covered by Build America, Buy America (BABA); Strongrate treads are made in Nantong, China. Privately funded projects are not affected; see Buy America (BABA).
Request a quote
Send tread length (stringer spacing), tread depth, number of treads, grating type, nosing color, design load and delivery ZIP code. Quotes within 1 business day (US Central time).
Sources
- Strongrate product catalog “Your Best FRP Solution” (Sep 2023), supplied by the site owner: stair treads, grating data, resins, clips and load tables (accessed Oct 17, 2026)
- OSHA 29 CFR 1910.25, Stairways (accessed Oct 15, 2026)
- Strongwell Section 06 74 13, FRP Pultruded Grating/Treads and Fabrications (revised Nov 2024): tread design loads (accessed Oct 15, 2026)
- Strongwell, Durability Study: Will Your 30 Year Old Grating Still Perform? (accessed Oct 15, 2026)
- DNV Type Approval Certificate TAF0000191 Rev. 1 (PDF on Strongrate’s ShipServ supplier profile) (accessed Oct 15, 2026)
- Federal Register 2023-17724; EPA Build America, Buy America FAQs for manufacturers (Jun 2025) (accessed Oct 15, 2026)