What to Check Before Accepting a Delivery of Fiberglass Grating Panels
A delivery of fiberglass grating panels arriving on site represents a significant project cost, and it arrives at a point in the project where the pressure to move quickly is usually high. The structural phase is either underway or waiting on the grating, the installation crew is scheduled, and the temptation to sign the delivery receipt and start unloading is strong.
That temptation is worth resisting long enough to do a proper receiving inspection. Problems found at delivery — wrong dimensions, damaged panels, incorrect resin system, color mismatch — are straightforward to resolve with the supplier. The same problems found after installation are substantially more complicated and expensive to address.
Start with the documentation before touching the panels
Before the panels come off the truck, the delivery should include documentation that confirms what was ordered. The items to verify from the documentation package:
Material certification: confirms the resin type (isophthalic polyester, vinyl ester, or phenolic), glass fiber type and content, and that the product was manufactured to the stated specification. If the project specified vinyl ester resin and the certification shows isophthalic polyester, that’s a rejection before a single panel is unloaded.
Test reports: for projects with fire rating requirements, the delivery should include copies of the fire test certificates (ASTM E84, or the project-specified standard) for the specific product being delivered. Self-certification is not adequate for fire-rated structural applications — independent laboratory test certificates are what the project specification typically requires.
Dimensional compliance: confirm that the panel dimensions on the delivery documentation match what was ordered. Molded grating is typically made to size, and a dimensional error caught from the documentation can be verified against the panels rather than discovered during installation.
Visual inspection of the panels
Once the documentation checks out, the panels themselves need to be inspected. A random sample of panels from different positions in the load (front, back, middle) is more representative than checking only the top layer.
What to look for on each panel:
Surface condition: the panel surface should be uniform in texture and color, with the grid pattern clearly defined and no significant surface voids, dry spots, or resin-poor areas. Dry spots — areas where the glass fiber is visible through insufficient resin coverage — indicate manufacturing quality issues. Small surface imperfections are acceptable; systematic dry areas are not.
Edge condition: panel edges should be clean and show the expected cross-section (fiber and resin through the full depth). Delamination at the edges — where the panel surface is lifting away from the edge profile — indicates manufacturing or handling damage. Check several panels for this, as edge damage can occur from panels sliding against each other in transit.
Color consistency: all panels in a single order should match in color. Color is derived from the resin pigmentation, and significant color variation within a batch indicates either inconsistent manufacturing or mixed production runs. Color variation that will be visible in the installed application should be raised with the supplier before installation.
Grid geometry: the mesh size (spacing between bars) and bar height should match the specification. A quick measurement with a tape measure on a few panels confirms dimensional compliance. For projects where the grating sits in a specific frame system designed for particular panel dimensions, confirming that the panels actually fit before unloading the full delivery prevents a very inconvenient reinstallation scenario.
Checking for transit damage
Fiberglass grating panels are relatively robust in transit when properly packed, but damage does occur. The most common forms of transit damage are:
Corner and edge chips: where panels have shifted against each other or against the crate edges. Small chips at panel corners or edges are typically cosmetic and don’t affect structural performance. Large chips or areas of significant fiber exposure need assessment — in corrosive environments, exposed fiber at damaged areas is a point of accelerated degradation that should be addressed with resin sealer before installation.
Surface cracking or crazing: a network of fine surface cracks, typically visible as a whitish area on the resin surface. Surface crazing without depth doesn’t affect structural performance, but deep cracking that extends through the resin layer to the fiber indicates structural damage from impact or stress during shipping.
Warped or distorted panels: fiberglass grating can warp if stored or transported in conditions that allow differential temperature or moisture exposure across the panel. Moderate warping often resolves when the panel is installed and constrained by the support structure, but significant warping — a panel that rocks on a flat surface under its own weight — may be difficult to install flat and should be flagged.
Quantity verification
Count the panels against the delivery documentation before signing. Partial deliveries and missing panels discovered after the truck leaves create delays while the shortage is resolved. If the count matches and the documentation and visual inspection pass, the delivery is accepted.
If panels are being rejected — whether for documentation failures, resin system mismatch, or significant damage — document the specific reason for each rejection clearly on the delivery receipt, photograph the relevant panels and the damage, and notify the supplier immediately. Having the rejected panels segregated from accepted stock prevents them from accidentally being installed.
Anti-slip surface verification
If the specification included an anti-slip surface — grit coating, concave bar tops, or meniscus profile — verify that the delivered panels have the specified surface. Grit-coated surfaces are obvious visually; the grit is visible and tactilely rough. Concave and meniscus bar top profiles are subtler and may require close inspection of the bar cross-section to confirm.
It’s worth checking this specifically because anti-slip surface is sometimes omitted from a production run if the order processing doesn’t clearly communicate the requirement, and the difference between a standard flat bar top and a concave or grit-coated top is not visible in a quick glance at the panel.
After acceptance: handling and storage until installation
Panels that pass receiving inspection should be stored in a way that protects them until installation. Fiberglass grating stores well in covered, dry conditions; outdoor storage is acceptable for short periods but extended outdoor exposure can begin to bleach the color from UV-sensitive resin pigments. Panels should be stacked flat rather than leaned vertically, with support under the full panel length to prevent warping.
For fiberglass grating panels going into corrosive environments, any handling damage that occurs between receiving and installation — chips, cuts, or scratches that expose fiber — should be sealed with compatible resin before installation. Sealing is easier before the panels go in than after, and addressing the damage at this stage costs minutes rather than hours.
The receiving inspection adds time to the delivery process but it’s time that’s well spent. The costs of addressing installation problems caused by specification errors, transit damage, or incorrect materials are almost always higher than the cost of doing the inspection properly at the point of delivery.
