Structural steel is a high-value trade where small errors get multiplied. Steel is usually priced per ton or per piece, so a missed column line or a wrong section size carries straight through material, fabrication, delivery and erection. This guide covers how to build a steel takeoff that can be checked, and how to think about the cost components on top of the tonnage.
Division 05 Scope
CSI MasterFormat Division 05 Metals includes:
| Section | Title | Typical items |
|---|---|---|
| 05 10 00 | Structural Metal Framing | Wide-flange beams and columns, HSS, braces, plates (05 12 00 Structural Steel Framing) |
| 05 20 00 | Metal Joists | Open-web steel joists, joist girders |
| 05 30 00 | Metal Decking | Roof deck, composite and non-composite floor deck |
| 05 40 00 | Cold-Formed Metal Framing | Load-bearing studs, joists, trusses |
| 05 50 00 | Metal Fabrications | Stairs, railings, ladders, lintels, gratings, embeds |
| 05 70 00 | Decorative Metal | Ornamental railings and architectural metalwork |
Joists and deck are often bought from specialty suppliers and may be erected by the steel erector under the same package. Miscellaneous metals may be a separate bid. Confirm what the bid package includes.
Know the Governing Documents
- AISC Code of Standard Practice — defines what counts as structural steel, how responsibilities for connection design are assigned, and tolerances. It affects scope and allowances.
- AISC 360 — the specification for structural steel buildings, used by the engineer of record
- Project specifications and structural general notes — grades, connection design responsibility (fully detailed, or delegated to the fabricator), coatings, fireproofing interfaces and inspection requirements
Common material grades include ASTM A992 for wide-flange shapes, ASTM A36 for plates and angles, ASTM A500 for HSS, and ASTM F3125 for high-strength bolts (which includes the former A325 and A490 grades). Always confirm grades against the project documents.
Tonnage Takeoff Method
Step 1: List every member
Work from framing plans, column schedules, elevations and sections:
- Beams and girders by mark, size and length, level by level
- Columns by mark, size and elevation range, noting splices
- Bracing by type and size
- Moment frames, transfer members and any members with special requirements
- Lintels, embeds, edge angles, pour stops and roof frames that may fall in the steel package
Step 2: Calculate weight
A wide-flange designation gives nominal depth and weight per foot. A W16x26 is nominally 16 in deep and weighs 26 lb per foot. For each member, weight = length x lb/ft. Tonnage = total pounds / 2,000.
Use lengths that reflect actual member length (typically column centerline to centerline, adjusted for connections), and be consistent.
Step 3: Add connection material
Plates, clip angles, stiffeners, base plates, cap plates, splice material and bolts add weight beyond the main members. Estimators commonly carry this as a percentage of main member weight, often somewhere in the 5-15% range depending on connection type. Moment connections and heavily braced frames sit at the high end. Where connections are detailed on the drawings, take them off directly instead of using a percentage.
Step 4: Count pieces
Erection cost depends heavily on piece count, piece weight and crane picks, not only on tons. Two jobs with the same tonnage can erect very differently if one has many light pieces.
Worked Example: Tonnage for a Framing Bay Group
Example: a small framing package includes twelve W16x26 beams at 30 ft, four W24x55 girders at 40 ft, and eight W10x33 columns at 14 ft. Assumption: 8% connection allowance.
Main member weight
| Members | Qty x length | Total LF | lb/ft | Weight (lb) |
|---|---|---|---|---|
| W16x26 beams | 12 x 30 ft | 360 | 26 | 9,360 |
| W24x55 girders | 4 x 40 ft | 160 | 55 | 8,800 |
| W10x33 columns | 8 x 14 ft | 112 | 33 | 3,696 |
| Total | 21,856 |
- Main member tonnage: 21,856 / 2,000 = 10.93 tons
- Connection allowance: 21,856 x 0.08 = 1,748.5 lb
- Total weight: 21,856 + 1,748.5 = 23,604.5 lb
- Total tonnage: 23,604.5 / 2,000 = 11.80 tons
- Piece count (main members): 12 + 4 + 8 = 24 pieces, or 24 / 10.93 = about 2.2 pieces per ton of main steel
Cost Components
Instead of relying on a single all-in dollar per ton, break steel cost into its parts. Each part has different drivers.
| Cost element | Main drivers |
|---|---|
| Mill material | Section sizes, grade, current mill and service-center pricing, availability |
| Detailing / shop drawings | Number of pieces and connections, complexity, revision cycles |
| Shop fabrication | Connection type, welding vs. bolting, number of cuts, holes and copes |
| Coatings | Primer, galvanizing or special coatings, surface preparation required |
| Delivery | Distance, number of loads, oversize or permitted loads |
| Erection labor | Piece count, picks per day, height, access, bolting and welding in the field |
| Cranes and equipment | Crane size for heaviest pick and reach, duration, mobilization |
| Inspection and testing | Special inspection requirements, weld and bolt testing |
For current pricing, use recent fabricator and erector quotes and a cost database such as RSMeans, adjusted with its City Cost Index for location. Our RSMeans cost data guide explains how to apply location factors.
Structural Steel Checklist
- Read the structural general notes and Division 05 specs before measuring
- Confirm who designs connections: engineer of record or fabricator
- Take off every member by mark, size and length, level by level
- Add connection material, directly measured or as a stated allowance
- Record piece counts and heaviest picks for erection planning
- Include base plates, anchor rods, leveling plates and grout interfaces
- List joists, deck, and miscellaneous metals separately if they’re in scope
- Note coating, fireproofing and inspection requirements
- Clarify what is included and excluded against the AISC Code of Standard Practice definitions
Common Mistakes
- Missing members that appear only in sections or elevations. Roof frames, kickers and edge members are often not on the main framing plans.
- Using one connection percentage for every job. A braced moment-frame building needs far more connection material than simple shear framing.
- Pricing by ton only. Light, piece-heavy framing costs more per ton to fabricate and erect.
- Overlooking delegated connection design. If the fabricator must design connections, engineering cost and schedule change.
- Not coordinating with other trades. Embeds in concrete, deck support angles and openings in deck may belong to different packages.
For related scope, see our concrete Division 03 guide and the material takeoff guide.
How F&K Estimatings Can Help
F&K Estimatings prepares structural steel takeoffs by member mark and size, with tonnage, stated connection allowances and piece counts, so you can price fabrication and erection with your own rates or your subcontractors’ quotes. See our structural steel estimating page, or read our guide to subcontractor bid leveling if you are comparing steel bids. Pricing and turnaround are on the pricing page.