Warehouse Steel Takeoff: Worked Example
Here's a complete warehouse steel takeoff with real numbers: a 100' x 200' single-story warehouse, 412 pieces of steel, 170,548 lbs (85.3 tons), landing at 8.5 psf of structural steel. We count the main frames off the grid lines, pick up the joists, girts, and bracing that most estimators underweight, and roll everything into tonnage you can check line by line.
If you want the general playbook for pricing these buildings — cranes, clear spans, mezzanines — that's covered in our warehouse and industrial steel estimating guide. This post is the takeoff itself, start to finish.
The Job: A Single-Story Warehouse Drawing Set
The example is a conventional hot-rolled warehouse, the kind of set that hits a small fab shop's inbox every couple of weeks:
| Parameter | Value |
|---|---|
| Footprint | 100' x 200' (20,000 sq ft) |
| Eave height | 25'-0", low-slope roof |
| Grid | Lines 1–11 @ 20'-0" (200' direction), lines A–B–C @ 50'-0" (100' direction) |
| Roof system | Open-web steel joists + 1.5" metal deck on wide-flange rafters |
| Walls | Metal panel on C8 girts |
| Drawing set | S0.1 notes, S1.1 foundation, S2.1 roof framing, S3.1–S3.2 sections and details |
| Scope | Columns, rafters, joists, girts, eave struts, rod bracing, base plates, connection material |
Deck, anchor bolts, and doors are by others on this one. Note that before you count a single piece — scope notes on page one of your takeoff save arguments later.
One simplification for the walkthrough: the endwall frames here match the interior frames. On a real job the engineer usually lightens the endwalls, so read your endwall elevations rather than assuming.
Counting Main Frames: Columns and Rafters from Grid Lines
The grid does most of the counting for you. Eleven numbered lines (1–11) crossing three lettered lines (A, B, C) means 33 column locations. The framing plan confirms it: W12x53 at the sidewalls (lines A and C), W12x65 at the interior line B, which carries twice the tributary roof area.
Rafters span the 50' from A to B and B to C at every numbered line: 2 rafters x 11 frames = 22 pieces of W21x62.
| Item | Section | Qty | Length | Total LF | lbs/ft | Weight (lbs) |
|---|---|---|---|---|---|---|
| Sidewall columns (A, C) | W12x53 | 22 | 25'-0" | 550 | 53 | 29,150 |
| Interior columns (B) | W12x65 | 11 | 25'-6" | 280.5 | 65 | 18,233 |
| Rafters | W21x62 | 22 | 50'-0" | 1,100 | 62 | 68,200 |
| Main frame subtotal | 55 | 115,583 |
Two habits worth copying:
- Count columns at grid intersections, then reconcile against the framing plan. If the plan shows 32 columns and the grid says 33, somebody deleted one at an overhead door or a pit — find out which before you price it.
- Interior columns run longer than sidewall columns when the roof slopes to the eaves. Here the ridge sits at line B, so the B columns pick up 6" of extra length. Small on one piece, real money across a bigger job.
Note the rafters are 40% of total tonnage by themselves. On warehouse work the main frames dominate the weight, so a wrong rafter count is the single most expensive mistake available.
Joists, Girts, Purlins, and Bracing: The Easy-to-Miss Tonnage
This is where warehouse takeoffs go wrong. The frames are big and obvious; the secondary steel is 200+ small pieces scattered across three sheets, and it adds up to about a third of the job.
Joists. 22K4 open-web joists span the 20' between rafter lines at 5'-0" on center. Across the 100' width that's 19 joists per bay, and 10 bays gives 190 joists. At the SJI catalog weight of 5.7 lbs/ft, that's 3,800 LF and 21,660 lbs. If you count joists off the plan one by one instead of doing spacing math, fine — but do the spacing math anyway as a check. Full detail on reading joist designations and bridging is in the bar joist takeoff guide.
Girts. Three rows of C8x11.5 on all four walls: sidewalls 2 x 3 x 200' = 1,200 LF, endwalls 2 x 3 x 100' = 600 LF. Shipping in 20' pieces, that's 90 girts and 20,700 lbs. Girts are the classic missed item because they live on wall sections and elevations, not the roof framing plan you've been staring at.
Eave struts. One line of C8x11.5 at each eave, 400 LF total, 20 pieces, 4,600 lbs.
Purlins. None on this job — the joist-and-deck roof replaces them. If this were a pre-engineered building you'd be counting Z-purlins at 5' centers instead of joists, and cold-formed Zs get counted by the row exactly like girts. The PEB takeoff guide walks that version of the roof.
Rod bracing. X-bracing in 6 wall bays and 6 roof bays: 24 rods of 3/4" diameter, roughly 1,030 LF at 1.50 lbs/ft = 1,547 lbs. Rods are nearly weightless next to the frames, but each one is a fabricated piece with clevises or bent ends — count them for labor even though they barely move tonnage.
| Item | Section | Pieces | Total LF | Weight (lbs) |
|---|---|---|---|---|
| Roof joists | 22K4 | 190 | 3,800 | 21,660 |
| Wall girts | C8x11.5 | 90 | 1,800 | 20,700 |
| Eave struts | C8x11.5 | 20 | 400 | 4,600 |
| Rod bracing | 3/4" rod | 24 | 1,030 | 1,547 |
| Secondary subtotal | 324 | 48,507 |
Notice the piece-count inversion: main frames are 68% of the weight in 55 pieces; secondary steel is 28% of the weight in 324 pieces. Your shop hours live in the piece count, not the tonnage.
Connections and Base Plates on a Warehouse Job
Base plates. One per column: 33 plates of PL 1" x 14" x 14" at 55.6 lbs each = 1,835 lbs. Anchor bolts are by others here (typical — the concrete sub sets them), but confirm it in the notes every time.
Connection material. Clip angles at every joist seat, rafter-to-column moment connections with stiffeners, girt clips, brace gussets. You can detail-count all of it, but at bid stage most shops carry an allowance on the hot-rolled frame weight. We're using 4% of the 115,583-lb frame subtotal = 4,623 lbs. On warehouses, 3–5% is the normal band — moment frames push you to the top of it, simple shear connections to the bottom.
The Roll-Up: Piece Counts to Tonnage with Real Numbers
| Category | Pieces | Weight (lbs) | % of total |
|---|---|---|---|
| Columns | 33 | 47,383 | 27.8% |
| Rafters | 22 | 68,200 | 40.0% |
| Joists | 190 | 21,660 | 12.7% |
| Girts + eave struts | 110 | 25,300 | 14.8% |
| Rod bracing | 24 | 1,547 | 0.9% |
| Base plates | 33 | 1,835 | 1.1% |
| Connection allowance | — | 4,623 | 2.7% |
| Total | 412 | 170,548 | 100% |
170,548 lbs = 85.3 tons. Divided by 20,000 sq ft, that's 8.5 psf of structural steel.
That psf number is your sanity check, and it's the first thing an experienced estimator computes after the roll-up. If this takeoff had come out at 4 psf, something big is missing — probably the girts or a whole rafter line. At 15 psf with no crane, something got double-counted. The math takes thirty seconds and catches five-figure mistakes.
For a second worked example on a different building type — a retail shell with beams and girders instead of joists — see the structural steel takeoff example.
Typical Warehouse Steel Weight per Square Foot
Benchmarks from typical single-story warehouse and industrial jobs. Use these to gut-check a roll-up, never to price one:
| Building type | Structural steel (psf) |
|---|---|
| Pre-engineered metal building, no crane | 4 – 7 |
| Light warehouse, joist/deck roof, ≤24' eave | 5 – 8 |
| Conventional hot-rolled warehouse (this example) | 7 – 10 |
| Distribution center, 32'+ clear height | 8 – 12 |
| Industrial building with 10–25 ton crane runs | 12 – 20 |
Drivers that push a job up the table: clear span (100' clear instead of our interior column line would roughly double the rafter weight), eave height, crane beams, snow and wind loads, and mezzanines — which add their own steel without adding footprint area, so they can distort a psf check if you forget to note them.
Same Takeoff with AI + Human Verification: Time Comparison
Manually, this set is a solid chunk of a day: page-by-page member counting, three passes for the secondary steel you missed the first time, weight lookups, and a spreadsheet roll-up.
| Step | Manual | AI + human verification |
|---|---|---|
| Read set, scope notes | 30 min | 30 min |
| Count frames, joists, girts, bracing | 3.5 – 5 hrs | ~10 min (automated detection) |
| Verify counts | (re-count passes, included above) | 30 – 45 min reviewing flagged items |
| Weight lookups + roll-up | 45 – 60 min | Automatic |
| Total | 5 – 7 hrs | ~1 – 1.5 hrs |
The shape of the work changes more than the clock does. Instead of building the count from scratch, you're verifying one: the software finds and boxes every member label on every page, and you confirm or reject what it found. Every piece in the count is a box you can see on the drawing — the 190 joists aren't a trusted formula, they're 190 marks you can audit. That verification step is why AI-assisted takeoffs hold 95–99% accuracy: detection does the counting, an estimator's eyes make it bid-grade.
Ready to test it on your own numbers? Run a warehouse set through SteelFlo — upload the PDF, get every member found and boxed across 4,500+ steel sections and 6 international standards, verify the counts, and export a BOM with the tonnage math done. The first 3 takeoffs are free, so a set like this example costs you nothing but the hour to check it.