CSI Division 03 Concrete Estimating: The Complete Guide

On many commercial projects Division 03 is one of the larger trade packages, and it carries real risk. Concrete volumes, rebar weights and formwork areas each need their own takeoff, and each has its own unit of measure and waste. A mistake in any one of them flows straight into the bid. This guide shows how to organize a Division 03 estimate and how to work each quantity, with a checked example.

Division 03 Scope in MasterFormat

CSI MasterFormat Division 03 Concrete is organized into these main sections:

Section	Title	What it typically covers
03 05 00	Common Work Results for Concrete	General requirements shared across concrete work
03 10 00	Concrete Forming and Accessories	Formwork, form ties, embedded items, waterstops
03 20 00	Concrete Reinforcing	Rebar, welded wire reinforcement, fibers, accessories
03 30 00	Cast-in-Place Concrete	Footings, walls, columns, slabs, finishing, curing
03 40 00	Precast Concrete	Structural and architectural precast
03 50 00	Cast Decks and Underlayment	Cast roof decks, gypsum and cementitious underlayment
03 60 00	Grouting	Non-shrink grout under base plates and equipment
03 70 00	Mass Concrete	Large placements with thermal control requirements
03 80 00	Concrete Cutting and Boring	Sawcutting, coring, openings in existing concrete

Read the project specification to see which sections apply. Items like vapor retarders, sealers, anchor bolts and underslab insulation are sometimes specified in other divisions, and that is where scope gaps start.

Ready-Mix Concrete Volumes

Measure by element and mix

Take off each element type separately: spread footings, continuous footings, grade beams, walls, columns, elevated slabs, slabs-on-grade, and so on. Keep them separate because:

• Mix designs differ (for example, 3,000 psi footings vs. 4,000 or 5,000 psi elevated slabs, air-entrained exterior flatwork)
• Placement methods differ (chute, pump, bucket)
• Labor productivity and finishing differ

The core formula

Concrete volume in cubic yards = length (ft) x width (ft) x depth (ft) / 27

Convert inches to feet before multiplying. An 8 in wall is 0.667 ft, and a 5 in slab is 0.417 ft.

Waste

Commonly used allowances are around 3-5% for direct chute placement and around 5-10% for pumped placement. Uneven subgrade, over-excavated footings and thin slabs push waste toward the high end. ACI 117 sets allowable construction tolerances. A slab placed on subgrade at the low end of its tolerance uses more concrete than the design thickness suggests.

Rebar Takeoff

Rebar is usually priced by weight, so the takeoff builds up lengths by bar size and converts them to pounds.

Bar size	Nominal diameter	Weight (lb/ft)
#4	0.500 in	0.668
#5	0.625 in	1.043
#6	0.750 in	1.502
#8	1.000 in	2.670

Steps:

1. Read the structural general notes for cover, lap splice requirements, hook details and any epoxy-coated or galvanized bar.
2. Take off each bar mark by size, spacing and length from plans, sections and schedules.
3. Count bars as (distance / spacing) + 1, rounding the spaces up.
4. Add laps. Lap splice lengths follow ACI 318 and the structural notes, which often provide a lap schedule by bar size. Either measure laps directly or apply a stated percentage.
5. Add dowels, corner bars, hooks, stirrups and ties, then accessories (chairs, bolsters, tie wire) as separate items.

Formwork (SFCA)

Formwork is measured in square feet of contact area: the area of form face in contact with concrete.

• Continuous footings: 2 sides x depth x length (where not poured against earth)
• Walls: 2 sides x height x length, plus bulkheads at ends and construction joints
• Columns: perimeter x height
• Slab edges: edge depth x perimeter
• Elevated slabs and beams: soffit area plus beam sides, with shoring or reshoring as a separate item

Separate job-built forms from rented or owned system forms. Reuse count drives the cost of each square foot.

Worked Example: Continuous Footing and Foundation Wall

Example: a building has 240 LF of continuous footing, measured on the centerline, 2 ft wide x 1 ft deep. A foundation wall 8 in thick x 4 ft tall sits on it. Assumptions: 5% concrete waste; footings formed both sides; three #5 continuous bars in the footing; #4 verticals at 16 in OC, 5 ft long including embedment; #4 horizontals at 16 in OC; 10% allowance for laps and waste. Corners and openings are ignored for simplicity.

Concrete

1. Footing: 240 x 2 x 1 = 480 CF; 480 / 27 = 17.78 CY
2. Wall: 240 x 0.667 x 4 = 640 CF; 640 / 27 = 23.70 CY
3. Net total: 17.78 + 23.70 = 41.48 CY
4. With 5% waste: 41.48 x 1.05 = 43.55 CY, ordered as 44 CY

Formwork

1. Footing: 2 sides x 1 ft x 240 LF = 480 SFCA
2. Wall: 2 sides x 4 ft x 240 LF = 1,920 SFCA
3. Total: 2,400 SFCA

Rebar

1. Footing #5: 3 bars x 240 LF = 720 LF; 720 x 1.043 = 750.96 lb
2. Wall verticals: 240 / 1.333 = 180 spaces + 1 = 181 bars x 5 ft = 905 LF
3. Wall horizontals: 4 ft / 1.333 = 3 spaces + 1 = 4 bars x 240 LF = 960 LF
4. Total #4: 905 + 960 = 1,865 LF; 1,865 x 0.668 = 1,245.82 lb
5. Net total: 750.96 + 1,245.82 = 1,996.78 lb
6. With 10% laps and waste: 1,996.78 x 1.10 = 2,196.46 lb, or 2,196.46 / 2,000 = 1.10 tons

A real foundation would also include corner bars, dowels into the slab, anchor bolts, waterproofing or dampproofing (Division 07) and backfill (Division 31). Each goes on its own line.

Division 03 Checklist

• Read the structural general notes and every Division 03 spec section
• List mix designs by element, including air entrainment and any special admixtures
• Take off footings, walls, columns, slabs and elevated work separately
• Record placement method for each pour (chute, pump, bucket)
• Build rebar by bar mark and size; apply laps per the structural notes
• Measure formwork SFCA, and list shoring or reshoring for elevated work
• Include finishing, curing, joints, sealers, embeds and vapor retarder
• Include testing, winter protection and hot-weather measures if the spec requires them
• Write RFIs for conflicting dimensions or missing details

Common Mistakes

• Unit errors. Multiplying inches by feet, or forgetting to divide by 27.
• Counting overlaps twice. Including the footing volume where a wall or pier sits on it, or double-counting slab and thickened edge.
• Missing laps and dowels. Taking off bars at net length with no lap allowance.
• Using one waste factor for everything. Thin slabs on rough subgrade need more than a formed wall does.
• Ignoring scope in other divisions. Vapor retarder, underslab insulation and waterproofing often fall between trades.
• Missing pump and small-load charges. Short-load and pump minimums add up on jobs with many small pours.

For more on the concrete trade, see our Division 3 concrete estimating guide and the material takeoff guide.

How F&K Estimatings Can Help

F&K Estimatings prepares Division 03 takeoffs organized by MasterFormat section, with concrete volumes by element and mix, rebar by size and weight, and formwork SFCA, plus a list of RFIs and scope-gap items. Structural concrete scopes are one of the areas Waqas Malik reviews. Learn more on our concrete estimating services page, or see turnaround and cost on the pricing page.