Understanding CSI MasterFormat Divisions
A comprehensive guide to the CSI MasterFormat system used for organizing construction specifications and estimates.
Numerical cost and allowance examples are illustrative, not market rates or measured company outcomes. Use the current project documents, supplier inputs and specified measurement conventions.
Understanding CSI MasterFormat Divisions
The Construction Specifications Institute (CSI) MasterFormat is the standard indexing system used in North America for organizing construction data, specifications, and estimating budgets.
Why MasterFormat Matters
Before MasterFormat, every architect and contractor organized specifications differently. By standardizing construction into 50 major divisions, MasterFormat ensures that communication across trades is uniform.
When preparing a Bill of Quantities (BOQ), estimators code every line item with its corresponding CSI code.
The Core Divisions (1995 vs 2004+)
While the old 16-division format is still sometimes seen, modern estimates use the expanded 50-division format.
Division 00-01: General Requirements
- Division 00: Procurement and Contracting Requirements
- Division 01: General Requirements (Overhead, PMs, Temp Facilities)
Division 02-14: Facility Construction
- Division 02: Existing Conditions (Demolition)
- Division 03: Concrete
- Division 04: Masonry
- Division 05: Metals (Structural Steel)
- Division 06: Wood, Plastics, and Composites (Lumber)
- Division 07: Thermal and Moisture Protection (Roofing)
- Division 08: Openings (Doors and Windows)
- Division 09: Finishes (Drywall, Painting, Flooring)
Division 21-28: Facility Services (MEP)
- Division 21: Fire Suppression
- Division 22: Plumbing
- Division 23: Heating, Ventilating, and Air Conditioning (HVAC)
- Division 26: Electrical
- Division 27: Communications
Related Knowledge
Related Guides
Publication Information
- Originally Published: July 2026
- Related References to Check: CSI MasterFormat
- Next Review: January 2027