How to do a structural steel takeoff, step by step

What a steel takeoff has to produce

A structural steel takeoff is the list of every piece of steel on the job: each member's size, length and count, its weight, and the work it needs in the shop. Everything else in the bid is built on it. Material cost comes from the weights, shop labor from the pieces and connections, erection from the piece count and tonnage, and freight from the total weight.

A good takeoff has three qualities. It is complete: nothing on the drawings is skipped, including the small items scattered through the architectural set. It is traceable: every quantity can be pointed to on a specific sheet, so a revision or a question from the general contractor can be answered in minutes. And it is organized: grouped by level, area or system in a way that pricing, alternates and change orders can use later.

The method below works whether you measure on paper with a scale rule or on screen. The order matters more than the tool: big, countable things first, then the details, then a deliberate check.

Step 1: Collect and organize the full set

Before you measure anything, make sure you have everything and know which version of each sheet is current.

• All disciplines, not just structural. Architectural sheets carry stairs, railings, canopies, lintels and support framing. Mechanical sheets show rooftop unit frames and dunnage. Civil and landscape sheets can hide bollards, site rails and trench grating.
• The project manual. Division 05 sections such as 05 12 00 Structural Steel Framing, 05 21 00 Steel Joist Framing, 05 31 00 Steel Decking, 05 50 00 Metal Fabrications, 05 51 00 Metal Stairs and 05 52 00 Metal Railings define materials, finishes, submittals and testing.
• Every addendum. Log each one with its date and the sheets it reissues. A superseded sheet left in the set is one of the most common sources of a bad number.

Build a drawing log: sheet number, title, revision and date. If the set arrived as one large PDF, split or bookmark it so you can jump to any sheet by number.

Step 2: Read the general notes and specifications first

The general notes sheet (often S-001 or S0.1) changes the price of every member on the job. Read it before you count anything and note:

• Material grades: ASTM A992 for W shapes, A500 Grade C for HSS, A36 for plate and angles, A53 Grade B for pipe are common, but check. A less common grade can change both price and availability.
• Connection design: whether connections are fully detailed on the drawings or delegated to the fabricator's engineer. Delegated design means engineering cost and more uncertainty in connection weight.
• Bolts and welding: bolt grade (ASTM F3125 Grade A325 or A490), slip-critical or snug-tight joints, and any field welding.
• Finish: shop primer, no paint, galvanized, or a high-performance coating system. Architecturally exposed structural steel (AESS) needs its own pricing.
• Inspections and testing: special inspections, ultrasonic testing of welds and who pays for them.

Step 3: Check every scale before you measure

A wrong scale makes every length on the sheet wrong by the same factor, and it is easy to miss. Check each sheet before you take anything off it:

• Find the printed scale under each plan and detail title. Details on one sheet are often drawn at different scales than the plan beside them.
• Watch for reduced prints. A half-size set measured at the printed 1/8" = 1'-0" gives lengths half as long as they should be. A graphic scale bar survives reduction; a written scale does not.
• Calibrate against the longest known dimension you can find, such as an overall grid dimension, rather than a short one. A small error on a short line becomes a large error across the building.
• Treat anything marked NTS (not to scale) as dimensions only. Never measure it.

Step 4: Set up a structure for the takeoff

Decide how you will group the takeoff before you start, and use the same structure on every job so anyone in the office can read it. A typical breakdown is by level (Foundation, 2nd Floor Framing, Roof Framing), then by system (columns, beams, bracing, joists, misc). Large jobs may need areas or phases as well.

Plan for alternates and typical floors now. If floors 3 through 8 are identical, take off one floor and repeat it, rather than measuring the same plan six times. If the bid has an add alternate for a canopy, keep that steel separate so it can be priced on its own.

Step 5: Columns, base plates and anchor rods

Columns are the easiest place to start because they are countable. Work grid line by grid line from the foundation plan and column schedule.

• Length: from the bottom of the base plate (or top of footing or pier, plus grout) to the top of steel elevation, plus any extension above the roof. Note splice locations on tall columns.
• Base plates: size and thickness from the schedule or details, one per column. Weigh them as plate.
• Anchor rods: count, diameter and length per column. Rods are often furnished by the steel contractor and set by the concrete contractor, so be clear about who sets them.
• Cap plates, splice plates and leveling plates where shown.

Count the columns against the grid as a check: a missing column at a grid intersection is usually a counting slip, not a design choice.

Step 6: Beams, girders and bracing

Work each framing plan systematically, bay by bay or grid line by grid line, so you never have to wonder whether a member was counted. Read the size tag on each member, such as W16X26, and measure from support to support.

Most estimators take beam lengths center to center of supports (grid to grid). The detailer will cut the actual piece shorter to fit the connection, so grid lengths are slightly conservative, which is usually what you want at bid time. Be consistent either way.

• Look for camber and shear stud callouts on each beam, commonly written beside the size, for example W21X44 (24) c=3/4" where (24) is the stud count. Both add cost.
• Pick up cantilevers, openings framed with angles or channels, and beams at different top-of-steel elevations.
• Take bracing from the frame elevations, not the plans. A diagonal's length is the hypotenuse of the bay width and story height.

Step 7: Joists, joist girders and deck

Open web steel joists are designated by depth, series and chord size: an 18K5 is 18 inches deep, K-series, chord size 5. Joists and joist girders are usually bought from a joist manufacturer, so your takeoff is a count and length per designation, plus bridging rows, for a quote. If you fabricate light joists in-house, take them off like any other assembly.

Metal deck is taken off by the square foot, by type and gage (for example 1.5" Type B, 20 gage roof deck, or composite floor deck). Deduct large openings, add pour stops and edge angles at slab edges, and note whether the deck is in your scope or bought out and installed by others.

Step 8: Connections and shop work

Connections are where steel estimates are most often light. Every beam has two ends, and each end needs a connection that costs material and shop labor. Count them deliberately:

• Simple shear connections: shear tabs or double clip angles, with the bolt count from the typical details.
• Moment connections: flange plates or direct welds, often with column stiffeners and doubler plates.
• Braced frame connections: gusset plates, which can be large and heavy.
• Copes, holes, stiffeners, studs and any shop welding the details call for.

If the drawings leave connections to the fabricator, base your allowance on your own history: the connection weight and shop hours on similar past jobs. That figure depends on your shop and the type of framing, so track it job by job instead of using someone else's percentage.

Step 9: Miscellaneous steel hiding in the set

Now sweep the whole set for the smaller items. They are individually cheap and collectively expensive to miss: loose lintels over masonry openings, ledger and shelf angles, embed plates, rooftop unit frames and dunnage, opening frames in deck, hoist beams, bent plate pour stops, bollards, ladders, stairs and railings.

Read every detail callout on the architectural sheets and every note that says "by steel" or "steel supplier". The steel estimating checklist lists the items most often missed.

Step 10: Check the takeoff before you price it

Checking is a separate step, not something you do while counting. Before pricing:

1. Confirm every sheet with steel on it has been taken off, and none of the takeoff sits on a superseded sheet.
2. Confirm every page you measured had a verified scale.
3. Compare total weight per square foot of floor area with similar jobs you have built. A big difference is not proof of an error, but it is a reason to look again.
4. Re-read the general notes and addenda against your takeoff: grades, finishes and any added scope.
5. Have a second estimator spot-check the largest members and the connection counts.

Doing it faster in Kredna

Kredna follows the same method, with the arithmetic and bookkeeping done for you. Drop the bid set in and sheet numbers are read from the drawings. Accept the printed scale in one click or calibrate on a dimension, and add scale regions for details drawn at a different scale. Press Space, type w16x26, press Enter and click the two ends: the member is drawn at the right length and weight, and the totals update.

On framing plans, Find members reads the size tags printed on the drawing and proposes the member each one labels, for you to accept by size. Takeoffs go into folders by level, repeat ×N for typical floors, and right-click Fabrication adds connections, holes, copes and welds that become shop hours. Superseded and unscaled sheets are flagged before you submit. See steel takeoff for the details.