Steel Estimating Guide: Structural Steel Takeoff and Costing

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

1. Main member tonnage: 21,856 / 2,000 = 10.93 tons
2. Connection allowance: 21,856 x 0.08 = 1,748.5 lb
3. Total weight: 21,856 + 1,748.5 = 23,604.5 lb
4. Total tonnage: 23,604.5 / 2,000 = 11.80 tons
5. 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.