Where concrete estimating actually wins or loses money
Concrete is one of the easiest trades to estimate badly and one of the costliest to estimate badly. The unit material cost is relatively simple — a cubic yard of 4000 psi normal-weight ready-mix runs $145 to $190 depending on region — but the layered costs around the concrete (formwork, rebar, embeds, pumping, placement labor, finishing) routinely account for 60-75% of total in-place cost. Get the formwork SFCA wrong and your concrete estimate is wrong by a quarter regardless of how precisely you counted cubic yards.
Vortex concrete estimates cover the full in-place cost — concrete, formwork, reinforcement, embeds, accessories, placement, finishing, and curing — at the level of detail your bid actually requires.
What we count
Concrete by element type and mix
Every concrete element on the plans gets counted separately by mix design and element type:
- Spread footings — width × length × thickness, by footing type
- Strip footings — width × depth × length, with continuous-run summing
- Mat / raft foundations — gross area × thickness with deductions for embedded items
- Pier and pile caps — by individual cap or pier
- Slab-on-grade — area × thickness, with separation by slab type (interior, exterior, structural, post-tensioned)
- Suspended slabs — area × thickness, with edge form length and drop-panel volumes called out separately
- Beams and grade beams — width × depth × length
- Columns — cross-section × height by column type, with cap and base detail
- Walls — height × length × thickness, with openings deducted
- Stair pans — slab volume plus tread and riser
- Curbs, gutters, walks — linear feet by section
Formwork (SFCA)
Formwork is measured in Square Feet of Contact Area (SFCA) — the surface area in actual contact with concrete. This is the universal industry unit for forming work because formwork unit cost is dominated by labor (cutting, bracing, stripping, cleaning) rather than material.
We break formwork down by reuse class and type:
- 1-time job-built lumber forms (highest unit cost)
- Multi-use job-built lumber forms (5-10 reuses)
- Manufactured snap-tie forms (Symons, EFCO, Doka, Peri)
- Gang forms for repetitive walls
- Slip forms for tall structures
- Metal pan forms for one-way joist slabs
- Coffered slab forms
Ties, accessories, oil, and shoring are itemized as separate lines.
Rebar
Rebar is counted bar by bar from the schedules or, where schedules aren’t yet final, computed from typical reinforcement ratios cross-checked against the structural notes. Output includes:
- Bar size (#3 through #18) and total quantity
- Length and bend type per piece, summed to total weight in tons
- Splices, accessories (chairs, bolsters, dowels, mechanical splices)
- Shop labor for fabrication and bending
- Field labor for placement
- Tie wire and tying labor
Embedded items and accessories
Anchor bolts, embedded plates, sleeves, expansion joints, water stops, vapor retarder, sub-base, capillary break, and curing compound — all itemized.
Concrete placement and finishing
Placement method (direct chute, pump, crane bucket, conveyor) priced separately from concrete material. Finishing labor by surface type — broom-finished, troweled, machine-troweled, stamped, polished, exposed aggregate. Saw cutting for control joints by linear foot.
Where formwork costs hide
If your concrete estimate is just “X CY at $Y per CY” you are missing the actual cost driver. Here’s a real-world cost breakdown for a typical commercial 8-inch suspended slab:
| Component | Cost per SF of slab | % of total |
|---|---|---|
| Concrete material (8” thick, 4000 psi) | $5.30 | 28% |
| Pumping | $0.85 | 4% |
| Placement labor | $0.95 | 5% |
| Finishing labor (troweled) | $1.10 | 6% |
| Rebar material | $2.40 | 13% |
| Rebar placement | $1.20 | 6% |
| Formwork (shoring + deck + edge forms) | $5.85 | 31% |
| Embeds, accessories, curing | $0.70 | 4% |
| Equipment, supervision, OH | $0.65 | 3% |
| Total in-place | $19.00/SF | 100% |
Formwork is 31% of the cost of a suspended slab. If your estimate skips it or short-counts it by 10%, you’ve shifted ~3% of your total bid into your own pocket — or out of it.
Concrete mix designs we routinely estimate
- 2500 psi flowable fill (CLSM)
- 3000 psi normal-weight footing and unreinforced slab mix
- 4000 psi structural slab mix (most common commercial)
- 4500-5000 psi structural columns, walls, beams
- 6000-8000 psi high-strength columns (high-rise)
- Lightweight concrete (LWC) for floor systems, fire-rated assemblies
- Self-consolidating concrete (SCC) for congested reinforcement
- Fiber-reinforced concrete (steel fiber, synthetic macro)
- Post-tensioned concrete slabs and beams
- Stamped and decorative concrete
How long a concrete takeoff takes
For most commercial projects under $15M, a complete concrete takeoff turns around in 24 to 72 hours. Bigger jobs — high-rise residential, large parking structures, industrial pours — take 5 to 10 business days. Same-day rush turnaround is available for emergency bid days at a 50% rush surcharge.