Concrete Estimating
Concrete estimating built from the structural drawings — cubic yards by placement, formwork by contact area, reinforcement by tonnage — so foundations, slabs, structures and site concrete are measured before the price is written.
Four Inventories in One Estimate
Concrete is the most forgiving material on the job to pour and the least forgiving to estimate cheaply. A concrete estimate is really four inventories carried out at once: volume in cubic yards, formwork in square feet of contact area, reinforcement in pounds and tons, and placing and finishing in labor hours. These four quantities share no units, which is precisely why concrete estimating mistakes tend to compound instead of cancel. A slab that reads as a single number on the floor plan breaks apart into subgrade preparation, concrete volume, edge formwork, reinforcement, curing labor, saw cutting and finishing — each priced, scheduled and bought differently.
On an average commercial structure, concrete is typically between 8 and 12 percent of the direct construction cost, but it is frequently the single largest subcontractor package on the project. That concentration of value makes measurement discipline expensive to skip. A two percent overrun on a five-thousand-yard foundation package is hours of placing labor, truck time and finishing crew nobody priced; a ten percent underrun on rebar is a structural component that must be bought out late at spot pricing. Neither shows up in the estimate — both show up on the bottom line.
CEDS prepares concrete estimates the way the field pours: by element, by placement, by day. Volumes are separated into footings, slabs, columns, decks and site work so your team can order concrete in the sequence the project actually pours it. Formwork is carried in square feet of contact area by element and facing class. Reinforcement is taken off by size and tonnage against the structural notes. Placing and finishing hours are built from stated production rates, so the estimate survives contact with the concrete subcontractor's real numbers.
For the full cost picture around a concrete package — labor, material, equipment and markups on the whole building — see our construction cost estimating service, and for measured quantities in every other trade our quantity takeoff service.
What a Concrete Estimate Covers
The estimate is organized the way the structural drawings are read — by element, from the ground up. Each scope below is measured with its own units and its own pricing structure, then rolled into a single summary.
Foundations
Footings, grade beams, piers, mat foundations and pile caps measured by volume, with excavation, backfill, mud mat and formwork quantified where the set requires them.
Slabs-on-Grade
Slabs measured as volume, surface area and edge work — vapor barrier, control joints, saw cutting, curing and finishing included against the spec.
Elevated Structures
Columns, beams, decks and slab-on-metal-deck taken off by volume and SFCA, with shoring, re-shoring and elevated placement labor carried separately.
Site Concrete
Approach slabs, equipment pads, curbs, sidewalks and paved areas quantified from the site and civil drawings, with forming and finishing priced per your specification.
Formwork
Wall, column, beam and slab formwork in square feet of contact area, with facing class, gang forming and reuse considerations stated on every line.
Reinforcing
Rebar taken off by size and tonnage across footings, walls, slabs and decks, with laps, splices, chairs, ties and supports added from the structural notes.
Concrete estimates are structured so each of these six scopes can be split out for a subcontractor quote, bought separately or trimmed as the design evolves. A foundation contractor and a flatwork contractor rarely receive the same files — the estimate keeps their scopes distinct even though they were measured from one drawing set.
How a Concrete Estimate Is Prepared
- 1
Structural Review
The structural and architectural sets are read together — footing schedules, section details, reinforcement notes, slab thicknesses and load paths — so the estimate is built from the actual design rather than the plan view alone.
- 2
Volume Calculations
Concrete volumes are calculated by element and placement type in cubic yards, including footing excavations, slab thicknesses, beam and column geometry and the disposal work the drawings rarely spell out.
- 3
Formwork Takeoff
Formwork is measured in square feet of contact area for every formed surface, with facing class, reuse and stripping assumptions carried on each line so the forming cost is adjustable, not fixed.
- 4
Reinforcement Takeoff
Rebar is counted by size and weight in pounds and tons, with laps, development lengths, chairs, ties and splices added from the structural notes rather than assumed.
- 5
Placing & Finishing Labor
Placing and finishing hours are built from production rates that match the placement type, pump or crane requirements, weather assumptions and the finish level in the spec.
A Sample Concrete Quantity Excerpt
The excerpt below shows how a concrete takeoff reads when it arrives — mixed units by element, ready to be priced against your supplier quotes and crew rates. This is a representative extract, not a complete set.
| Item | Description | Qty | Unit |
|---|---|---|---|
| Structural Footings | Continuous and isolated, fc′ = 4,000 psi | 620 | CY |
| Grade Beams | Including excavation, backfill and mud mat | 180 | CY |
| Foundation Slab | 5″ slab on grade, vapor barrier and saw-cut joints | 38,400 | SF |
| Slab Concrete | 5″ × 38,400 SF surface | 595 | CY |
| Columns | 24″ round, floors 1–4 | 240 | CY |
| Elevated Deck | 6″ slab on composite metal deck | 1,380 | CY |
| Wall Formwork | 12″ high, gang formed, both faces | 46,200 | SFCA |
| Column Formwork | Steel forms, four reuses in plan | 18,900 | SFCA |
| Rebar — Walls & Footings | #5 to #8, incl. laps, chairs and ties | 96 | TON |
| Rebar — Decks & Slabs | #4 at 12″ o.c. each way, installed | 42 | TON |
Sample figures are illustrative only and are shown to demonstrate how a concrete quantity takeoff reads. Your estimate is prepared from your project's own structural drawings and specifications.
What You Receive
The deliverable is a concrete quantity package organized for a bid and a pour schedule — every element measurable, every assumption stated and every unit consistent with how concrete is actually bought and placed.
- Quantity Summary
- A single summary of concrete, formwork and reinforcing by element and placement, ready for your bid sheet or subcontractor solicitation.
- Placement Breakouts
- Volumes separated by placement type and day — footings, walls, decks, slabs — so you can schedule deliveries in the order the project pours.
- Assumption Log
- Waste factors, lap assumptions, finish levels and every unmeasurable item written down before a single cost is applied.
- SFCA Detail
- Formwork in square feet of contact area with facing class and reuse assumptions attached to every line.
- Review Call
- Time to walk the quantities with the estimator before you commit the concrete number to your bid.
Assumptions That Move the Concrete Number
These are exactly the lines where a concrete subcontractor and a general contractor disagree after award. The general contractor sizes the job from measured volume; the subcontractor prices it from the conditions the drawings force — a forming gang that cannot reuse, a pump required by site access, rebar that laps more than the plan shows. A concrete estimate that states those assumptions up front turns the argument into a documented conversation rather than a surprise change order.
- Volumes separated by element and placement type, never blended into one cubic yard total
- Footing excavations and backfill quantified from the drawings, not assumed by rule of thumb
- Slabs measured for both volume and surface area so finishing and joints price correctly
- Formwork carried in SFCA with facing class and reuse stated on every line
- Rebar by size and tonnage with laps, chairs, ties and splices added from the structural notes
- Waste factors stated clearly instead of buried inside a unit price
- Placing and finishing hours built from production rates you can compare to your own crews
- Pump, crane and finishing assumptions documented for every placement
Bid With a Sheet You Can Hand Over
"Two weeks before a 60,000-SF warehouse bid, our structural set was still being coordinated. CEDS measured the slab, footings, formwork and rebar in six days and flagged every assumption the incomplete details forced. We bid the concrete with a quantity sheet we could hand straight to the subcontractor on day one."
Concrete contractor, Texas — distribution center slab and foundations
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Send your structural drawings and we'll confirm the elements covered, the level of detail and the turnaround for your concrete estimate.
Concrete Estimating Questions
Most concrete quantities are measured in cubic yards (CY) for volume and square feet for surface work, but a complete estimate mixes units on purpose: formwork in square feet of contact area (SFCA), rebar in pounds and tons, slab-on-grade in both square feet and cubic yards, and placing labor in hours or crew-days. The unit follows the buying decision — concrete is ordered by the yard, forming is bought by the square foot of contact, and steel is bought by the ton.
Waste depends on the work. Continuous footings and slabs poured in even geometry run 3 to 6 percent. Small, heavily formed elements, odd shapes and site work typically run higher, up to 8 to 10 percent, because of truck short loads and form waste. We state the waste factor as a separate line rather than hiding it in a unit price, so you can tighten or loosen it against your own supplier terms.
Yes, but only as the structural notes allow. Laps, development lengths, splices, chairs, ties and support wire are added from the reinforcement details in the set rather than from a flat percentage. When a detail is missing, the lap assumption is logged explicitly so the buyer knows exactly what the tonnage includes and can adjust it when shop drawings firm up.
We can, at the detail the set supports. From a schematic or designation-development structural set we prepare an order-of-magnitude figure by element type, with confidence stated and assumptions logged. From a structural set missing only a few details, we measure everything that is defined and itemize what is assumed. The estimate is refined against the same baseline as drawings evolve, so early budgets stay credible through the design process.
Formwork is measured in square feet of contact area (SFCA) and then priced by element and facing class. Walls, columns, beams and elevated decks have different forming costs because of facing, reuse and gang potential. Carrying SFCA by element lets your team price a column gang with four reuses differently from a one-time architectural wall facing — the two are never the same number.