Who This Checklist Is For
If you are a contractor, engineer, or facility manager who needs to order metal grating, fiberglass grating, or perforated metal for an upcoming project, this guide is for you. It assumes you have a basic understanding of what grating is—the load-bearing, slip-resistant walkway material you see in industrial plants, mezzanines, and drainage trenches. This is not a primer on materials.
Instead, this is a five-step checklist I wrote from my chair as a quality compliance manager. Over the past four years, I have reviewed roughly 200+ unique grating orders annually for our 50,000-unit yearly volume. I have rejected about 12% of first deliveries in 2024 (the rate dropped this year; it was closer to 18% in 2023). Most rejections were preventable. Here is what I check before a single piece of steel or fiberglass enters our warehouse.
Step 1: Confirm Your Bearing Bar Orientation (and Don't Trust the Drawing)
This is the single most common error I see, and it is almost always on the engineering drawing, not the shop drawing. The bearing bars are the load-carrying members of a grating panel. For standard steel grating, they run the length of the panel. The cross bars are the smaller rods perpendicular to them.
The mistake happens when a spec calls for "span over supports" without double-checking the drawing. I had a $22,000 project delayed last year because the bearing bars were running in the wrong direction for the support structure. Normal tolerance here is zero: if the bars are wrong, the panel cannot carry the load.
What I tell every new vendor: send me a marked-up photo of your shop drawing showing the bearing bar direction relative to the support. Not a CAD file—a real photo (circa 2022, I started requiring this after the redo). If they hesitate, it is a red flag.
Step 2: Verify Your Material Grade with a Mill Test Report (MTR) or a Scratch Test
For steel grating, you need to know the exact grade: ASTM A36 is standard, but you may need A572-50 or even stainless steel 304/316L. Most vendors will say "commercial grade" or "standard steel." That is not a spec. That is a guess.
Here is something vendors won't tell you: a "standard" steel grating from one supplier can have a yield strength that is 20% lower than a "standard" from another, depending on the origin of their steel coils. We saw this in a batch of 200 panels last year. The material failed a physical bend test. The vendor claimed it was “within industry standard,” but their MTR showed a yield strength of 36 ksi, which is the minimum for A36. Our project required 44 ksi minimum. We rejected the batch, and they redid it at their cost. Now every contract includes a minimum yield strength requirement in the PO.
Verification tip: Ask for the MTR before the order ships. For smaller orders where an MTR is cost-prohibitive, ask for a physical scratch test on a cut-off piece (if it scratches easily like aluminum, it is not high-strength steel). I do not have hard data on how often the grade is wrong industry-wide, but based on our experience, it is roughly 1 in 15 orders that has a grade discrepancy.
Step 3: Check the Surface Finish and Cutting Quality (The 5% Rule)
For custom fabrication—cut-to-size panels, notched corners, hole drilling—how the edge is finished matters. When you order grating cut to size, the cut edges are typically left as cut (sharp) unless you specify otherwise. This is a safety issue, not just aesthetics.
I run a blind test with our team: same grating panel with cut edges ground smooth versus not ground. 70% identified the ground panel as "more professional" without knowing the difference. The cost increase was about $1.50 per linear foot of cut edge. On a 500-panel run with average 4 cut edges per panel (so 2,000 linear feet of cut edge), that is $3,000 for measurably better perception and safer handling.
What most people don't realize is that CNC plasma cut edges on steel grating require a secondary grind to remove the slag and sharp burrs. If the order is rushed, the grinding step is the first to be dropped. (Ugh, I have seen this happen three times this year.) The correct spec is "cut edges ground smooth and de-burred." Include that in your PO as a yes/no requirement.
Step 4: Test the Non-Slip Surface on Fiberglass Grating (with Wet Boots)
If you are ordering fiberglass grating for a wet environment—chemical plant, water treatment, drainage—the non-slip surface is the most critical feature. The standard spec is a "grit top" where silica carbide is embedded into the resin surface. But not all grit tops are equal.
The spec usually says something like "minimum 0.5mm grit depth." I have seen deliveries where the grit was barely visible—almost a dusting. The vendor said it met the standard. Let me rephrase: it met the minimum standard, but it was functionally useless in wet conditions.
The insider tip: ask for a sample coupon (a 2"x4" piece cut from a previous run). Put water on it. Step on it with a wet boot. If it feels dicey, it will be dicey at scale. The simplified rule of "grit top = non-slip" ignores the huge difference between a deep embed and a light dusting. We upgraded our spec to "minimum 1.0mm grit depth" and customer feedback on slip incidents dropped by an anecdotal 34% in the first year (I wish I had tracked this more rigorously, but the improvement was clear).
Step 5: Confirm the Galvanizing Spec (Hot-Dip vs. Pre-Galvanized)
This is the one I see most people miss. Steel grating is often galvanized for corrosion protection. But there are two types: pre-galvanized (the steel sheet is galvanized before fabrication) and hot-dip galvanized after fabrication (the entire finished panel is dipped).
The difference? Pre-galvanized has thinner coating at the cut edges and weld points. Hot-dip after fabrication coats the entire panel, including the cut edges. For outdoor or corrosive environments, hot-dip after fabrication is the standard. But it costs more—roughly 8-12% more than pre-galvanized, based on our pricing from 2023 and 2024.
Too often, a buyer sees "galvanized" on a quote and assumes it is hot-dip. When the grating arrives, the cut edges are rusting within three months. That is not a material defect; it’s a spec gap. Normal tolerance for rusting on cut edges of pre-galvanized in a mild environment is about 6-12 months. If you want no rust on cut edges for 15 years, you need hot-dip after fabrication.
Sample spec for your PO: "Galvanizing per ASTM A123 (hot-dip after fabrication). Minimum coating thickness: 3.9 mils (100 microns)." Include that verbatim.
Common Mistakes and What to Avoid
Here are the three most common errors I see repeated by first-time buyers:
- Ordering "standard" without defining it. Standard is a trap. Use the ASTM or NAAMM spec numbers. For steel grating, that is NAAMM MBG-534 or ASTM F1267 for fiberglass.
- Forgetting to specify the banding and packaging. Unbanded grating panels shift in transit, damaging the edges. Specify steel banding at both ends, edge protectors, and a weatherproof cover if stored outside.
- Not verifying the supplier's Quality System. Ask if they have a documented QA checklist. A vendor who says "we have a QC guy who checks things" is different from one who says "our QC process includes a dimensional check, a material verification, and a finish inspection with a written sign-off." The latter can be audited.
Final note on self-reference: This checklist worked for us, but we are a mid-size B2B company with predictable ordering patterns and a rigid QA process. If you are a small contractor doing occasional one-off buys, your calculus might be different. I can only speak to our context. If you are dealing with international sourcing or tiny budgets, there are factors I am not aware of. (As of April 2025, at least, the advice above is current.)
— A quality compliance manager who has seen enough.
