How Steel Subs Bid and Bill Commercial Work

A commercial steel package usually bundles several spec sections: structural steel (05 12 00), steel joists, metal deck (05 30 00 in the federal guide specifications), and often miscellaneous metal fabrications (05 50 13), which the federal guide writes as its own section covering items like bollards, roof hatches, cover plates and steel door frames (UFGS 05 50 13). The sub holding the subcontract is often the fabricator, with a detailer, an erector, a joist supplier and a galvanizer below it. The federal structural steel section ties the work to the AISC Code of Standard Practice: erection "must be in accordance with the applicable provisions of AISC 325, ANSI/AISC 303 and 29 CFR Part 1926, Subpart R" (UFGS 05 12 00).

Where steel sits in the job, and who is waiting on it, is laid out in the construction project lifecycle. The foundations and anchor rods it lands on belong to the concrete sub; see how concrete subs bid and bill.

Steel is measured by weight, but weight alone does not price a job. Two buildings with the same tonnage can cost very different amounts if one has many moment connections and heavy plates and the other is simple beams on shear tabs. Take off each of these and keep them on your estimate so the GC can compare bids on the same basis.

Write the tonnage your number assumes on the bid, and the add and deduct price per ton for changes. Steel prices move between bid and mill order, so say how long the price holds and whether it carries an escalation term.

If the drawings leave a gap, ask through the bid's questions so every bidder prices the same thing, and know that a GC leveling steel bids will read your exclusions line by line (how GCs level subcontractor bids).

The federal structural steel section says to "submit fabrication drawings for approval prior to fabrication", and that they "must not be reproductions of contract drawings" (UFGS 05 12 00). Its submittal list is a fair picture of what a steel submittal register looks like on most commercial jobs:

• Erection and erection bracing drawings, showing the sequence of erection, temporary shoring and bracing.
• Fabrication drawings, including details of connections, with the location, type and size of bolts and welds.
• Connection design calculations, signed and sealed by a registered professional engineer, where connection design is delegated to the fabricator.
• Product data for shop primer, welding electrodes, bolts and grout; test reports for bolts and welds.
• Certificates: AISC Certified Structural Steel Fabricator (AISC 207, Category BU) and Certified Erector (Category CSE) where the project requires them, welding procedures, welder qualifications, the certified welding inspector and the NDT technician.

Metal deck has its own list: fabrication drawings, deck design data, product data and samples, and certificates such as welder qualifications and powder-actuated tool operator (UFGS 05 30 00). The structural steel section also has an optional paragraph that gives welder qualifications a shelf life: where the qualification date is more than six months old, it asks for a current certificate that the welder has had no break in welding service greater than six months. Because shop drawings are submitted by sequence, plan the register by sequence and give each one a need date; how to prepare a submittal covers the package itself.

Steel cannot start erecting on a handshake. Before authorizing steel erection, "the controlling contractor shall ensure that the steel erector is provided with" written notice that the concrete in the footings, piers and walls (and the mortar in masonry piers and walls) has reached "either 75 percent of the intended minimum compressive design strength or sufficient strength to support the loads imposed during steel erection", and that any anchor bolt repairs, replacements and modifications were done as the rule requires; and the erector "shall not erect steel unless it has received written notification" of the strength (29 CFR 1926.752). Put a line in your bid that erection starts on receipt of both notices, and log the date you receive them.

Most of a steel subcontract is spent before anything reaches the site, so a schedule of values with one "structural steel" line leaves you financing the job. Split it the way the money goes out: detailing, mill material, fabrication by sequence, coatings, joists and deck as their own purchases, then erection by sequence. A sample for a two-sequence building:

Fabrication percent complete is really tons or pieces finished in the shop divided by the sequence's total, so keep that count behind every number you bill.

The fictional "Tamsin Ridge Steelworks" holds the $1,184,000 subcontract above with 10% retainage. In period 3, detailing finishes (70% to 100%), the second half of the mill material arrives at the shop and is billed as stored under the subcontract's terms, and sequence 1 fabrication goes from 40% to 85% of its tonnage. Nothing is on site yet.

This period bills $71,700 of work plus $148,000 stored = $219,700. Retainage at 10% is $21,970, so these lines add $197,730 to the payment due. Checks: $43,400 + $18,600 = $62,000; $148,000 + $148,000 = $296,000; $47,200 + $53,100 = $100,300 = 85% of $118,000; $238,600 + $219,700 = $458,300.

Those three lines alone are $458,300, about 39% of the contract, with no steel erected. Mill material sitting at the shop needs the backup your subcontract asks for (invoices, title, insurance, photos) before the GC will pay it; how stored lines carry from one pay app to the next is in how a subcontractor fills out a pay application.

Because steel bills early, retainage on it is held for a long time: in the example, $45,830 is already retained on three lines before erection starts. Ask at subcontract time whether retainage can be reduced once the frame is erected and accepted, rather than waiting for the whole building; how to calculate retainage shows the arithmetic.

Steel changes are priced by weight and by timing: a revision before the mill order costs pounds at your unit rate, while the same revision after fabrication adds scrapped pieces, re-detailing, shop hours and re-handling. Write the change order request as soon as an RFI answer or a returned drawing changes what you build (how to write a change order request).

• As-built fabrication and erection drawings reflecting field changes.
• Mill test reports, bolt certifications and weld inspection and NDT reports, where the spec asks for them.
• Fabricator and erector certifications and the welder qualifications submitted during the job.
• The warranty letter the subcontract calls for, with its start date.
• Final lien waivers from your lower tiers (detailer, erector, joist and deck suppliers) and the retainage release request.

Steel owes little of the usual closeout package (no training, rarely an O&M manual), so tie line 14 to the documents it does owe. For the rest of the sub's job from bid to final payment, see the subcontractor's guide.

A GC's steel package in Trade bids shows the sub its scope items, alternates and addenda. The sub asks questions on the invitation (answers go to every bidder without the asker's name), acknowledges each addendum, and submits a base bid with each scope item marked included or excluded, an optional breakout, alternates, exclusions and qualifications, plus its proposal PDF. There is no tonnage or unit-price field: put the tonnage basis and per-ton adds and deducts in your qualifications or the attached proposal.

Under contract, the sub bills in Pay apps: percent complete this period and materials stored per line, with previous billing carried forward and no line billed past 100%. Retainage uses the contract's one rate on completed and stored work, and the GC can send back a single line with a note. Mill invoices and storage photos attach to the pay app as files; a stored line has no field for where the material is or its bill of sale, and lines are dollars, not tons.

Steel is won on tonnage and kept on timing. State the tonnage and per-ton rate you priced, name every furnish-only and install-only item at the trade's edges, and plan the submittal register by sequence, because each approval is the release to fabricate.

Before your next steel bid, split your schedule-of-values template into detailing, mill material, fabrication and erection by sequence, so you can bill the money you have already spent.

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1. UFGS 05 12 00, Structural Steel (August 2018, change 2) — Whole Building Design Guide (USACE, NAVFAC, AFCEC). Read October 22, 2026.
2. UFGS 05 30 00, Steel Decks (May 2015, change 2) — Whole Building Design Guide (USACE, NAVFAC, AFCEC). Read October 22, 2026.
3. UFGS 05 50 13, Miscellaneous Metal Fabrications (August 2024, change 1) — Whole Building Design Guide (USACE, NAVFAC, AFCEC). Read October 22, 2026.
4. 29 CFR 1926.752, Site layout, site-specific erection plan and construction sequence — Electronic Code of Federal Regulations. Read October 22, 2026.