In commercial construction estimating, Division 03 is the designated category for concrete materials, reinforcement, and formwork. Standardized by the Construction Specifications Institute (CSI) MasterFormat, this division helps estimators, general contractors, and designers organize project scope.
Understanding what falls within Division 03 is essential for preparing clear, complete bids.
Core Categories of CSI Division 03
Division 03 is divided into several sub-categories, each representing a different phase of concrete construction:
03 10 00 Concrete Forming and Accessories
This section includes all temporary and permanent structures used to hold wet concrete in place:
- Wood, steel, or aluminum formwork panels.
- Shoring systems and structural supports for elevated slabs.
- Form release agents and stripping labor.
- Form ties, chamfer strips, and keyway forms.
Formwork contact area (calculated in Contact Square Feet, or SFCA) must be measured accurately, as formwork often represents a significant portion of concrete labor costs.
03 20 00 Concrete Reinforcing
This section includes structural reinforcement components:
- Steel rebar (reinforcing bars), including stirrups, dowels, and hooks.
- Welded wire reinforcement (WWR) or wire mesh for crack control.
- Rebar accessories, including chairs, bolsters, and tie wire.
- Fiber reinforcement (micro-fibers added to the concrete mix).
Reinforcing steel is typically priced by weight, requiring estimators to convert linear feet of rebar to tons based on bar size weights.
03 30 00 Cast-in-Place Concrete
This is the largest section of Division 03 and covers the concrete material itself:
- Footings, piers, grade beams, and foundation walls.
- Slab-on-grade slabs, elevated slabs, and concrete toppings.
- Ready-mix concrete deliveries, specifying compressive strengths (PSI).
- Concrete placing, consolidating, and finishing labor.
03 40 00 Precast Concrete
This section covers concrete elements fabricated off-site:
- Precast concrete lintels, coping, and sills.
- Precast structural columns, beams, and hollow-core slabs.
- Tilt-up concrete panels (sometimes categorized here or in cast-in-place).
What is Excluded from Division 03?
A common takeoff mistake is including items that belong in separate divisions. The following concrete-related scope items are typically excluded from Division 03:
- Earthwork and Excavation (Division 31): Trenching, backfilling, and subgrade preparation.
- Granular Subbase (Division 31 or 32): Gravel or crushed stone beds placed under slabs.
- Masonry Mortar and Grout (Division 04): Mortar for CMU blocks and grout used to fill block cells.
Final Thoughts
Structuring your concrete takeoff around standard CSI Division 03 codes ensures that your bid is organized and professional. It helps general contractors evaluate your proposal quickly, reducing bid-day confusion and protecting your project margins.