Molded vs. Pultruded Fiberglass Grating

FRP Grating Overview

Bedford has been providing much of the country, and parts of the world, with high-quality FRP (Fiberglass Reinforced Plastic) structural profiles and systems since 1974. What started as a small family business in a barn is now a 200+ employee operation in a 200,000+ square-foot manufacturing space. We often get asked the question: “What is the difference between fiberglass pultruded grating and fiberglass molded grating?” We’ll break it down so you can easily understand the differences.

Pultruded Fiberglass Grating

At Bedford, we offer a wide selection of pultruded FRP grating panels. Our PROGrate pultruded grating products are great for industrial floor systems, walkways, work platforms, stairs, ramps, trench covers and commercial-grade catwalks. This type of grating is lightweight and won’t corrode.
Pultruded FRP fiberglass grating diagram that shows the different layers — glass roving, glass mat, surface veil, and resin.

Bedford’s pultruded grating provides:

Corrosion resistance – This type of grating has the strength of steel, and it won’t corrode and breakdown like steel can.

Safety – Our grating features an epoxy anti-skid coating for enhanced traction. It also meets the specifications set forth by the Virginia Graeme Baker Act for use in VGBA compliant drain systems.

Extended life – Our grating has the ability to withstand the elements of nature. Resin provides the resistance to the environment, (i.e., the corrosion resistance, the UV resistance, the impact resistance, etc.) and the glass provides strength, in addition to safety from fire.

Easy fabrication – A major advantage of pultruded FRP grating is that the panels are lightweight. Therefore, they are easy to transport and work with, and you can easily cut and fabricate them by using standard tools.

Pultruded Fiberglass Grating Process

During the pultrusion process, a caterpillar-like machine grips the raw materials and “pulls” them through a series of steps until the finished profiles reach the cut-off saw.

Fiberglass roving and mat is pulled through guides on an automated and continuous cycle. Next, the profile receives a resin bath. Then, it is wrapped with a surface veil before being pulled through a heated die. The final task is to assemble the load bearing bars, groove and notch rod. The bearing bars are drilled on 6″ centers along the length and the cross rods are inserted and secured with epoxy perpendicularly to the bearing bar to form panels.

A high glass-to-resin ratio (65% glass to 35% resin), increases the stiffness along the length of the bearing bar (and panel) allowing for longer spans or higher loads in one direction.

This type of FRP grating offers builders a wide variety of panel sizes, and flexibility because it is assembled and not molded. This helps to reduce waste, or scraps of FRP in comparison to the molded fiberglass grating process.

Related: Learn more about the pultrusion process.

Molded Fiberglass Grating

Proven corrosion resistance is just one of the benefits of our PROGrid molded FRP grating. It’s strong, lightweight and performs reliably for years, even in extreme conditions. Top-surface options also provide excellent slip resistance for worker safety. Molded fiberglass grating is great for stair treads, decks, fasteners and pedestals.

Bedford Molded Fiberglass Grating Provides:

Stock – FRP molded grating is available in stock panels, or we are able to fabricate to size to meet your specifications. We’re also able to design, engineer and fabricate complete fiberglass grating systems, creating stair assemblies, catwalks, platforms, etc.

Extended life – You won’t have to replace molded FRP grating as often as other materials. The best part is you won’t have to repaint thanks to our molded-through color process.

Less waste – Interwoven square mesh construction provides bi-directional strength, so you can cut our FRP grating to fit and make the most efficient use of each panel.

Easy fabrication – You can easily cut and fabricate by using standard tools, in order to construct industrial platforms and walkways.

Molded Fiberglass Gratings Process

Technical illustrations of PROGrid molded FRP grating showing bonded glass and resin coating.With molded grating, instead of the fiberglass being constantly pulled through a series of steps, liquid resin and continuous fiberglass rovings are laid thoroughly in a mold, layer after layer, to produce the desired thickness and panel dimensions. Once this is done, the mold is set aside to cure. When it’s time, the panel is removed from the mold and then cleaned and prepared for this unique process to start again.

To ensure its quality and sturdiness, molded grating is cast in one piece, which means that there is no mechanical joint between bearing bars. The higher percentage of resin in molded fiberglass gratings also helps provide high-quality corrosion resistance and optimal impact resistance. Also, molded fiberglass grating that has a square mesh pattern offer a substantial load capacity because of their bi-directional strength.

As you can see, there are similar benefits to both pultruded fiberglass and molded fiberglass grating. It all depends on the application and where the pieces will be installed (e.g. – industrial stair towers, platforms, catwalks). To find out different uses of these fiberglass pieces take a look at our resources page which highlights design and installation insights, as well as general product literature.

For questions, or to learn more about ordering fiberglass reinforced plastic grating, contact us here.