The Industry Standard vs. the Steel Specialist
On-Screen Takeoff (OST) by ConstructConnect has been a staple in estimating departments since the early 2000s. It's the tool many estimators learned on — straightforward digital measurement for lengths, areas, and counts across every construction trade.
Steelflo is a newer, narrower tool: AI-powered takeoff built exclusively for structural steel. It detects members automatically from PDFs, looks up section weights, and generates BOMs without manual counting.
If you're a steel fabricator currently using OST and wondering whether there's something faster, here's the honest comparison.
How Each Tool Handles Steel
On-Screen Takeoff: Measure and Count
OST gives you a set of digital measurement tools on top of your PDF plans:
- Open the structural drawing
- Calibrate the scale
- Use the Count tool to click on each steel member
- Use the Linear tool to measure member lengths
- Create conditions for each section type (W12X26, HSS6X4X1/4) — manually
- Assign conditions to measurements
- Link to Quick Bid for cost estimating, or export
OST measures geometry. It doesn't know what a W-shape is, what it weighs, or how to classify it. That's all on the estimator.
Steelflo: Detect, Verify, Export
- Upload the structural PDF
- Set the drawing scale
- AI detection runs — identifies every steel member, classifies by type, looks up section weight
- Review detections on the source page with bounding box overlay
- Confirm or reject
- Export BOM, CSV, order sheet with nesting, or highlighted PDF
The AI handles identification, classification, and weight lookup. The estimator handles verification and judgment.
Side-by-Side Comparison
| | Steelflo | On-Screen Takeoff | |---|---|---| | Detection | AI-powered automatic | Manual click-to-count | | Steel section database | 550+ AISC + EN/BS/AS profiles | None built-in | | Weight lookups | Automatic per-section | Not available — noted by users as a gap | | International standards | AISC, EN, BS/IS, AS/NZS auto-detected | None | | Trade focus | Structural steel only | All trades | | Platform | Web browser (any OS) | Desktop (with mobile viewing) | | Pricing | Free trial, then $399–$1,499/mo | Starts at ~$15/user/mo | | AI features | Core product | "Takeoff Boost" (newer, limited scope) | | Nesting/cut optimization | Built-in | Not included | | Cost estimating | Pricing engine built in | Requires Quick Bid (separate product) |
Where OST Makes Sense
You're a multi-trade estimator. If steel is one part of a broader estimate that includes concrete, mechanical, and electrical, OST's generic measurement tools work across everything. One tool, one workflow.
Your team already knows it. OST has been around for 20+ years. If your estimators have decades of muscle memory with it, the switching cost is real.
Budget is tight. At ~$15/month to start, OST's entry price is hard to beat. If you're a one-person shop doing 2-3 steel bids a month, the cost math might not justify a specialized tool yet.
You need Quick Bid integration. If your cost estimating workflow runs through Quick Bid, OST's native integration is valuable. Steelflo has its own pricing engine but doesn't connect to Quick Bid.
Where Steelflo Makes Sense
Steel is your primary trade. OST was built for general construction measurement. It has been specifically noted in user reviews as "not great for structural steel" because it lacks material weight data. If steel is what you do, a tool built for steel works better than a generic measuring tool.
You need section weights. This is OST's most cited gap for steel work. When you count a W12X26 in OST, the tool doesn't know it weighs 26 lbs/ft. You need an external reference or manual calculation for every section. Steelflo looks up weights automatically from standard-specific databases — AISC, EN, BS/IS, and AS/NZS.
You want automated detection. Clicking on every steel member across a 30-page structural set is tedious, error-prone work. The most common takeoff mistakes — missed members, miscounts, transposed designations — come from the manual identification step that Steelflo automates.
You work with international drawings. OST has no concept of steel naming standards. Steelflo auto-detects which standard a drawing uses and routes to the correct detection patterns and weight databases.
You want a complete steel workflow. OST measures quantities but doesn't generate BOMs, calculate weights, optimize cut lists, or produce order sheets. Steelflo does all of this in one flow — detection through fabrication-ready export.
The Weight Data Problem
If you've used OST for steel, you've felt this pain. You spend time counting and measuring members, then you need weights — and OST can't help. You either:
- Look up every section in an external reference (AISC manual, spreadsheet, website)
- Build custom conditions with weight formulas manually
- Export raw counts to Excel and add weights there
Every one of these approaches adds time and introduces error opportunities. Steelflo eliminates this entirely — the weight lookup happens at detection time, automatically, for every supported standard.
A Note on Takeoff Boost
ConstructConnect recently added "Takeoff Boost," an AI-assisted feature for OST. Details on its structural steel capabilities are limited — it appears focused on architectural plan automation rather than structural sheet detection. If you're evaluating OST specifically for its AI features, test it on your actual structural drawings before committing.
Is On-Screen Takeoff Good for Steel?
OST works for steel takeoffs but it's a manual process with no built-in steel data. User reviews specifically note the lack of material weight information as a gap for structural steel estimators.
Does On-Screen Takeoff Have Steel Section Weights?
No. OST does not include steel section weights, properties, or an AISC shape database. Estimators must reference external sources or manually build custom conditions.
How Much Faster Is Steelflo Than On-Screen Takeoff?
For the detection and classification phase, significantly faster — AI detection takes minutes versus hours of manual counting. The total time difference depends on drawing set size, but larger packages (20+ pages) show the biggest gap.
Can I Use Steelflo and On-Screen Takeoff Together?
Yes. You could use Steelflo for steel detection and quantification, then use OST for non-steel measurement tasks on the same project if your workflow requires it.
Does Steelflo Work on Mac?
Yes. Steelflo is a web application that runs in any browser on any operating system — Mac, Windows, Linux, iPad.
Try Steelflo on a Drawing You've Done in OST
The best comparison is your own. Upload a structural PDF you've already taken off in OST. Compare the quantities, check the weights, and time the workflow.
Start free at steelfloai.com — one AI takeoff, no credit card.