Steel Grating · Stair Treads · Trench Covers
Same photo, same price per square metre, 24% less steel — and you cannot see it, weigh it by eye, or argue about it once it's bolted down. Below is your own RFQ line, taken apart token by token.
Anatomy Of One RFQ Line
This is the line most grating enquiries arrive as. Every token in it locks something down — and every gap between the tokens is a decision the mill gets to make for you, in its own favour, without breaking a single promise.
| What you wrote | What it actually locks | Room the mill still has | Month eight on site | How we rewrite it |
|---|---|---|---|---|
| Steel grating | The product family. Not the process, not the steel. | Press-locked vs welded. And the big one: hot-rolled flat bar vs slit strip — slit strip runs to negative tolerance, so "3.0" arrives at 2.7. | 8–10% less steel across the whole order, burred edges that hold zinc badly. | Welded, Q235B, hot-rolled bearing bars, thickness to plus tolerance |
| 30×3 | Nominal section. Depth carries load; thickness carries life and cost. | Which way the tolerance runs, and whether serration is cut into the 30 or added above it. | 2.7 mm bar looks identical, but less steel under the same zinc rusts through sooner. | 30(+0/−0)×3.0, negative tolerance rejected, serrated bar cut from 32 |
| 30/100 | Bar pitch — and this single number is the invoice. | 30 mm pitch is 33 bars/m. Open it to 40 mm and it's 25 bars/m: about a quarter of the steel, gone, invisible in a photo. | Heels catch, tools drop through, load rating falls, and it fails any anti-fall opening rule. | Bearing pitch 30 mm (33 bars/m), cross rod 100 mm, counted on arrival |
| HDG | Only the words "galvanised". | Hot-dip vs electro-zinc vs silver paint — an order of magnitude apart. And when it's dipped: before or after cutting. | Electro-zinc bleeds rust in the first year; a chemical plant does it faster. | Hot-dip to ISO 1461, stated coating class, dipped after all cutting |
| serrated | That teeth exist. Somewhere. | On every bearing bar or every second one; tooth depth; whether net height was restored after serrating. | Anti-slip in name only, and if teeth ate into the depth, every load figure you were given is void. | All bearing bars serrated, tooth depth stated, net depth maintained |
| 1000×5800 mm | Panel outline. Nothing about orientation or span. | Which way the bearing bars run, what they span onto, and whether cutting to size happens at the mill or on your site. | Bars laid the wrong way and the panel has no rated capacity at all; site-cut ends are bare steel. | Bearing bars parallel to the short side, clear span stated, cut to net size at the mill |
| 500 m² | A billing unit. Not a product. | Whether that's net opening area or purchased area — on shaped work the cutting waste runs 8–20% — and whether you settle by area, weight or panel count. | It covers eight tenths of the job, and the shortfall is another full container cycle away. | Panel schedule (N panels / M types) plus theoretical weight, both stated |
| — load class | Nothing. So the mill assumes "strong enough to survive lifting". | It picks the lightest bar that ships without folding, because nothing in your line says otherwise. | The platform bounces underfoot; one forklift pass leaves a permanent set. | 5 kN/m² pedestrian or stated wheel load, clear span, deflection ≤ L/200 |
| — edge banding | Nothing. It's the first line dropped from a cheap quote. | Every cut end and free edge can be left open. | Bearing bars splay at the free edge, the edge sags, and it trips people. | Banding bar of equal section to all cut and free edges; toe plate height where required |
| — clips & frame | Nothing — and grating quotes exclude the frame by default. | Fixing clips (four per panel) and embedded angle frame both quietly fall outside the price. | An unfixed panel flips when a forklift clips it. This is grating's most common serious accident. Unlocked street covers get stolen. | 4 saddle clips per panel, bolted clamps in traffic areas, hinge + lock on covers, frame supply stated explicitly |
| — cut-outs & schedule | Nothing. "500 m²" is really 180 panels, 43 types, 26 pipe penetrations. | Nobody is responsible for turning your drawing into a cutting list. | Your crew cuts on site: no banding, no zinc, rusting within weeks. | Supplier issues the panel cutting schedule for your approval; all cutting and penetrations before galvanising |
| — marking | Nothing. The panels arrive without identity. | Bundled however is convenient for loading. | Two workers spend three weeks matching panels to openings. | Unique stamped ID per panel, bundled by installation zone, ID-to-drawing map supplied |
Orange bars are what you wrote. Dashed grey bars are what the quotation is silent about — and silence is always resolved in the mill's favour.
The third row, in one picture
Relative steel content at the same bar section. A quarter of the material can leave the order through this one field, and the panel photographs the same.
Changes Are Cheap Until They Aren't
Grating goes through one door it cannot come back through: the zinc bath. Everything before it is editable, everything after it is a new panel. This is what a change actually costs at each stage.
The single most expensive sequencing mistake in this product. Galvanise before cutting and you paid hot-dip prices for electro-zinc life: every cut edge and every penetration is bare steel, and it shows within weeks.
Nesting is only worth doing once. We put a named day on the schedule approval; after it, changes are priced, not absorbed. That one date is what keeps a shaped order from drifting a month.
Grating quotes exclude the embedded angle frame by default, and half the disputes we're called into are exactly this. It gets written down before the order, in one line, either way.
Before The Container Is Even Opened
Grating is one of the few products where you can audit the order without unpacking it. Work out what it should weigh, then compare that against a number the port already measured for you.
What it should weigh
Multiply by your area and you have the weight the container should carry. No supplier data needed — this is just geometry and the density of steel.
What it actually weighs
Every container has a VGM — Verified Gross Mass, weighed at the port and required by law before loading. Subtract the tare printed on the door and the dunnage, and you have the cargo weight, measured by someone with no stake in your order.
Within a couple of percent of theoretical: fine. More than 5% light and you have your answer before a single band is cut.
Ask us for the VGM with the shipping documents. It costs nothing and it is the only independent measurement in the whole chain.
If it comes up light, three cuts find out why — in this order
Cut one · a tape measure
Lay a metre across the panel and count bearing bars. Should be 33; if you count 25, the pitch was opened and roughly a quarter of the steel never existed. This is the most common and most profitable substitution — and it needs no instrument at all.
Cut two · a caliper
Bar count correct? Then check thickness on ten bars and average. Slit strip run to negative tolerance turns 3.0 into 2.7 and takes 8–10% of the steel with it.
Cut three · the same caliper
Then cross rod section and pitch, then bar depth (measure at the tooth root on serrated panels). If all three cuts check out, what's missing is zinc — and that's a coating gauge question, not a weight question.
A tape, a caliper and a coating gauge cost less than a site lunch. We run this at the mill before shipment and send you the readings with the panel IDs; you run the same three cuts at your end. If the two don't agree, that is our problem to fix, not yours. How inspection works.
What We Ship
The panel is the cheap part. What turns 500 m² into a finished platform is the schedule, the banding, the clips and the marking.
Cut to your openings with penetrations banded, not standard panels for your crew to cut.
Send the drawing →Nosing, end plates and fixing centres — the three things a tread quote usually leaves out.
Send tread size →Frame, hinge and lock decided before the order, because street covers walk away without them.
Send channel size →Where depth, thickness and tooth depth are agreed in writing rather than assumed.
Check my section →Four clips a panel, banding on every cut edge, and the frame question answered in the order.
Include them →Every panel stamped and bundled by installation zone, with a map. Saves weeks on site.
Ask for the map →You pay the factory invoice. We add nothing to it. We earn from China's export VAT rebate — 9–13% depending on the HS code — paid by the state to the exporter of record after the goods leave. It is not a kickback from any mill. No mill pays us anything, which is exactly why we will tell you your line reads 30/100 but your quote was priced at 40. How we get paid, in full.
Ideally a drawing of the openings; failing that, the bar section, bar pitch, panel sizes, coating, whether serrated, the load it carries and its clear span — plus whether you need the frame. If you only have "500 m² of 30×3", send that and we'll come back with the questions that decide the price rather than a number that means nothing.
Almost always the bar pitch, the bar thickness tolerance, or the coating — in that order of impact. Bar pitch alone can move a quarter of the steel. Send us both quotes and we'll tell you which field each one is quietly using.
Yes, and it should be. Send the drawing, the mill returns a panel cutting schedule for your approval, then cuts, bands every edge, adds the penetrations — and only then galvanises. Cutting on site after galvanising leaves bare steel exactly where water sits.
By default no — grating quotes are for panels. The embedded angle frame, and often the clips, sit outside the price unless someone says otherwise. We put it in writing either way before the order, because this single omission causes more disputes on this product than anything else.
Grating is dense — a container reaches its weight limit long before it runs out of space, so the honest planning number is weight, not area. Tell us your build and total area and we'll give you the theoretical weight, the number of containers, and what else could ride in the leftover space.
If this order is a repeat of standard panels from a mill already audited and paid, a middleman adds cost and nothing else — say so and we'll leave it alone. We earn our place on shaped work with a cutting schedule, on a first order from an unknown mill, or when several suppliers have to arrive in one container.
Send the RFQ line you were about to email out, or the drawing. You get back the same line with the gaps filled in, and a price that is comparable to something.
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