A steel structure package is not a product with a single specification, so two suppliers can both quote for the same drawing and still be offering different things. When the numbers differ, the reason is usually the scope boundary rather than the tonnes.
This guide lists the items that have to be lined up before a price comparison is meaningful, and the questions that reveal where the differences are.
The items that change the number
| Item | What to compare |
|---|---|
| Supply scope | Structure only, structure plus roof and wall system, or a wider package including accessories |
| Weight basis | Quoted tonnage and the assumed profile list, so the same members are priced |
| Material grade | Grade and impact class, not just the strength number |
| Secondary steel | Purlins, bracing, sag rods, edge trims and their coating |
| Connections | High-strength bolts, anchor bolts, base plates and embedment supply |
| Surface treatment | Shot-blast grade, coating system and dry film thickness, or galvanizing standard |
| Design responsibility | Who produces and approves shop drawings, and who signs off connection design |
| Documents | Mill certificates, inspection records, packing list and loading photographs |
| Packing and loading | Bundling, marking, protection and the container plan |
| Freight and insurance | Which Incoterm applies, and who books and pays the main carriage |
| Exclusions | Everything the supplier is explicitly not providing |
Normalise before you compare
- Send the same scope document, drawing set and BOQ to every supplier.
- Ask for the quotation to be split into structure, envelope, accessories, coating, packing and freight.
- Require the quoted tonnage to state the assumed density and the member schedule it came from.
- Ask each supplier to quote on the same Incoterm and the same destination, otherwise the freight is not comparable.
- Require the same coating system in writing, including the dry film thickness.
- Confirm whether inspection, third-party attendance and documentation are inside or outside the price.
Signals that a quotation is incomplete
- A single lump-sum price with no tonnage and no member basis.
- Coating described only as "painted" or "galvanized" without a standard or thickness.
- No mention of who is responsible for shop drawings or connection design.
- Bolt supply and connection hardware not mentioned at all.
- Packing described as "suitable for sea transport" with no bundling or marking detail.
- Freight, insurance and destination charges quoted without naming the Incoterm and the place.
None of these signals means the supplier is wrong. They mean the quotation cannot be compared yet, and the missing information has to be requested before a decision.
Questions worth sending with the enquiry
- What exactly is excluded from this price?
- What tonnage is assumed, and from which member schedule?
- Which coating system and total dry film thickness is included?
- Are high-strength bolts, anchor bolts and base plates included?
- Who produces the shop drawings, and who approves them?
- Which documents are issued with the shipment?
- Which Incoterm and which named place does the price refer to?
- What is the payment schedule, and what triggers each payment?
This guide describes general practice for steel structure projects. It is not a design, and it does not replace the specification or the engineer responsible for your project.