Structural steel estimating, answered
One question, one page, one direct answer. Takeoffs, estimating, and the software that does it.
Steel Takeoff
Counting and measuring structural steel from drawings: what a takeoff is, how it is done, and how accurate it needs to be.
How do you calculate steel tonnage from a takeoff?
Multiply each line's quantity by its length in feet and by the shape's weight per foot to get pounds, sum every line, and divide by 2,000 for US tons. W, C, S, and WT callouts carry the weight per foot; HSS, pipe, angle, and plate weights come from the AISC shapes table.
MHow long does a structural steel takeoff take?
By hand, columns and beams on a mid-size commercial job take one estimator four to five days, with joists, braces, connections, and misc steel adding more, and each mid-bid addendum costing about a day. With AI-assisted detection and the estimator reviewing every number, the same scope finishes in under an hour, and 10,000-ton jobs in two to six hours.
JWhat does a structural steel takeoff example look like?
A structural steel takeoff example is a line-item sheet: one row per member group with shape, size, quantity, length, weight per foot, and total weight, grouped by level and sheet, with connection material, plates, and anchor rods listed below the framing subtotal. Totals roll up to tons. A worked two-story frame follows.
MWhat is a structural steel quantity takeoff?
A structural steel quantity takeoff, often just called a steel takeoff, is the count and measurement of every steel member in a drawing set, recorded by shape, size, length, and weight per foot. It produces the piece count, the tonnage, and the takeoff sheet or BOM that a steel bid is priced from.
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Structural Steel Estimating
Turning a takeoff into a price: material, shop labor, erection, freight, and the numbers estimators use to sanity-check a bid.
Takeoff vs estimate: what's the difference?
A takeoff is the count: every column, beam, joist, brace, connection, and misc item pulled off the drawings, with piece counts and tonnage. An estimate is what you do with that count, applying material prices, labor rates, coatings, freight, and margin to reach a bid number. In structural steel the takeoff is usually the slower half.
MWhat does a structural steel estimator do?
A structural steel estimator decides which invitations to bid are worth pursuing, reads the drawing set, performs the takeoff of every column, beam, and connection, prices material, shop labor, coatings, freight, and erection, and submits and defends the bid. After award, that estimate becomes the budget the shop is held to.
JWhat drives shop hours per ton in structural steel?
Shop hours per ton is fabrication labor divided by tonnage, and it moves with connection type, average piece weight, repetition, extra operations such as copes, cambers, and studs, finish requirements like AESS or galvanizing, and material form. Two jobs of equal tonnage can differ widely, which is why the number has to come from your own job history.
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Steel Detailing & Drawings
Reading structural drawings, schedules, and details, and how detailing fits between design and fabrication.
What are IFC drawings?
IFC drawings are the set issued for construction, the design team's release that the project can be built from, superseding earlier issues of the sheets it covers. The same letters also name Industry Foundation Classes, the open BIM file format, so context decides which is meant. Steel is often bid earlier, on 30 or 60 percent or issued-for-bid sets.
MWhat is a 30 percent or 60 percent drawing set?
A 30 or 60 percent set is a construction document issue the design team labels with its own estimate of completeness. At 30 percent expect missing column schedules and unsized members; at 60 the frame is mostly real but connections and misc steel are not. Steel bid off these sets gets re-estimated when the finished design lands.
JWhat is a column schedule?
A column schedule is the table on the structural sheets listing every column with its section size at each tier, splice elevations, and base plate, keyed either by grid intersection or by marks like C1. Column takeoff starts there, because columns change size as they rise. When a set has none, the estimator builds one before counting.
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Revisions, Addenda & Change Orders
How drawing changes are issued, tracked, compared, and priced on a steel project.
Addendum vs change order: what's the difference?
An addendum changes the bid documents before the contract is awarded, and its cost is absorbed into the bid. A change order modifies the signed contract afterward, priced and negotiated on its own. Bulletins and ASIs deliver the drawing changes in between; the change order is where their cost and schedule impact gets agreed.
JHow do you compare two drawing revisions?
Compare full sets, not clouded sheets: match every sheet between issues, compare pair by pair starting with the schedules, list each change against the takeoff, reconcile deletions across addenda so nothing is counted twice, then re-run tonnage and record the delta. Revision clouds are a starting checklist, never the change list.
JRevision cloud
A revision cloud is the scalloped bubble a drafter draws around a changed area of a drawing, paired with a numbered revision triangle and an entry in the title block's revision history. It marks what someone chose to call out, not everything that changed, so estimators treat clouds as a starting checklist rather than the change list.
MWhat is an addendum in construction?
An addendum is a formal change to the bid documents issued while a project is still bidding, before the contract is awarded. It is numbered, becomes part of the contract documents, and must be acknowledged in the bid. For a steel estimator, each addendum reopens the takeoff, because the count has to carry every change.
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Software & Tools
What steel estimating, takeoff, and fabrication software actually does, what it costs, and how the tools fit together in a fab shop.
Can you do a steel takeoff in Bluebeam?
Yes, with limits. A Bluebeam steel takeoff means counting members and measuring lengths on the PDF with Revu's count and measurement tools, then exporting the markups list to a spreadsheet for weights. Revu does not know steel shapes, read a column schedule, or total tonnage, so the spreadsheet does the steel part.
MCan you use sheet metal estimating software for structural steel?
Not effectively. Sheet and plate tools price parts whose quantity is already known, using cut length, nest yield, and machine time. Structural steel needs the count derived from framing plans and a column schedule first, then shop hours that swing with connection type. A job shop tool has no concept of a W-shape or a moment connection.
JHow is steel estimating software priced?
Steel estimating software is sold five ways: per seat, per trade license, per takeoff or per sheet, as a flat annual subscription, or as a module inside a fabrication management system. Almost no vendor publishes list prices. The total depends more on user and project caps, implementation, and the annual layer than on the headline figure.
JIs FabSuite the same company as Tekla PowerFab?
Yes. Trimble acquired FabSuite in April 2018 and relaunched it in March 2019 as the core of Tekla PowerFab, renaming the management system Tekla EPM. In 2023 Trimble retired the EPM name, so the product is now simply Tekla PowerFab. A shop still running FabSuite is on the legacy version of PowerFab, not a rival.
JIs there AI-based steel takeoff software?
Yes. AI steel takeoff software uses machine learning to detect steel members on framing plans and read the callouts, schedules, and details around them, returning a draft takeoff instead of a blank sheet. Ferra, SketchDeck LIFT, Steel Genie, Beam AI, and Exayard are examples as of September 2026. Accuracy tracks drawing quality, and every output needs an estimator's review.
MIs there free steel takeoff software?
No. There is no uncapped free steel takeoff software, but three free routes exist: a spreadsheet built on the AISC shapes table, the measuring tools in a free PDF reader, and free or trial accounts on paid products, capped by sheets or days. On a four-hundred-sheet set the counting is the cost, and free removes none of it.
JWhat is steel takeoff software?
Steel takeoff software reads a structural drawing set and produces the member list an estimator prices: every beam, column, brace, and plate with its size, length, and weight. It replaces counting by hand or marking up a PDF. General construction takeoff software measures areas and lengths but does not know what a W12x26 weighs.
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Glossary
Short definitions of the terms used across structural steel estimating, detailing, fabrication, and erection.
AESS
AESS is architecturally exposed structural steel: steel left visible in the finished building and fabricated to the appearance requirements of AISC 303 Section 10, categories AESS 1 through 4 plus custom category C. The steel is the same; the labor is not, and unpriced AESS scope is one of the fastest ways to lose money on a bid.
MKip
A kip is 1,000 pounds of force, a contraction of kilopound, equal to 4.448 kilonewtons. Structural drawings state beam end reactions, axial loads, and moments in kips and kip-feet. Estimators read them as a pricing signal: big reactions mean heavy connections, and heavy connections mean shop hours.
MMiscellaneous metals
Miscellaneous metals is the fabricated metal work outside the main frame: stairs, railings, ladders, lintels, embeds, and support frames, specified under Division 05 metal fabrications. It is labor-dense and priced by the piece rather than the ton, much of it is drawn late or not at all, and scope gaps between trades live here.
JShear studs
Shear studs are headed steel pins welded to a beam's top flange, usually through the metal deck, so the concrete slab and the beam act as one composite member. The count rides the beam callout, such as W18x35 (26), and it belongs in the takeoff: missed studs across a floor are real money.
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