How to Prepare a Bill of Quantities for Steel Structures (Step-by-Step)
From reading the drawings to signing the bid form — the six steps a quantity surveyor or estimator follows to turn structural steel drawings into a priced, tender-ready BOQ.
Review Drawings, Specifications & Owner Requirements
Before pricing anything, read the Issued-for-Construction (IFC) drawings and structural specifications end to end. Note the governing design codes (typically AISC 360 and ASCE 7 for wind/seismic loads), the steel grades specified (commonly ASTM A992 Gr.50 for W-shapes, A572 Gr.50 for plates/HSS), and any project-specific requirements like a threshold building special inspection plan.
Classify Every Steel Component by Structural Role
Group members by role, not just shape: perimeter/corner columns, internal columns, upper-level columns, primary floor beams, secondary/infill beams, transfer beams, vertical and horizontal bracing, roof trusses, purlins and girts. Members with a different role carry materially different section sizes and connection complexity, so they need separate line items and separate rates — never one blended $/ton figure for "steel columns."
Take Off Quantities From the Drawings
For linear members, multiply total length by the standard unit weight from the AISC Shapes Database. For plates (base plates, gusset plates, stiffeners), multiply volume by steel density (7,850 kg/m³ or 490 lb/ft³). Add an agreed wastage allowance (commonly 3–6%) for cutting and fabrication loss. Keep supply and erection tonnage co-terminous by member group so the two sections reconcile.
Structure the BOQ Into Sections
Organize the priced items into standard sections so the document reads logically and reviewers can compare bids section-by-section:
A–B: Supply & Erection
The bulk of the tonnage value, split by member group.
C: Connections & Welding
Bolts, anchor rods and site welding, priced per EA or per Lb.
D–E: Protection & Envelope
Painting, fireproofing, galvanizing, decking and cladding.
F–H: Misc, QC & Mobilization
Stairs/handrails, testing/inspection, and crane/temp works.
Skip Steps 1–4
Our structural steel BOQ template already has this exact section structure built in — just plug in your own quantities.
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For at least your highest-value items, show the build-up: raw material cost (incl. wastage), fabrication or erection labor, consumables, then add works/site overheads and profit margin as explicit percentages. A visible rate analysis is what lets an owner's quantity surveyor accept your number instead of challenging it, and it's what the standard quantity-surveying methodology calls for on any significant line item.
Cross-Check Tonnage, Then Issue
Before issuing, run an independent sanity check: total priced steel tonnage divided by gross floor area should land within a typical lb/SF steel-intensity range for the building type and wind region (a braced steel-frame office building in a high-wind region is commonly in the 12–16 lb/SF range). A material take-off tab that flags a large variance here catches mis-keyed quantities before they reach a bidder.
Frequently Asked Questions
Typically a quantity surveyor, cost estimator, or the structural engineer's office, often in coordination with the fabricator during the shop-drawing stage.
For a mid-size commercial project, expect several days for an experienced estimator working from complete IFC drawings — longer if drawings are still in development.
You can still build a provisional BOQ using preliminary member sizes, clearly marked as subject to revision, then update quantities once drawings are issued for construction.
Skip the Blank Spreadsheet
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