CSI MasterFormat Divisions 01–33 Explained for Estimators

CSI MasterFormat, published by the Construction Specifications Institute (CSI) and Construction Specifications Canada, is the standard list of titles and numbers used to organize construction specifications, cost data and bid packages in North America. Estimators use it to structure takeoffs, scope sheets, bid forms and budgets. The 2018 edition uses divisions 00 through 14, 21 through 28, 31 through 35 and 40 through 48; older projects may still use the pre-2004 16-division format, where mechanical was Division 15 and electrical Division 16.

Procurement and general requirements

• Division 00 – Procurement and Contracting Requirements: bid forms, instructions to bidders and conditions of the contract.
• Division 01 – General Requirements: project administration, submittals, temporary facilities, quality control and closeout.

Facility construction (Divisions 02–14)

• 02 Existing Conditions — demolition, abatement and site assessment.
• 03 Concrete — forming, reinforcing, cast-in-place and precast.
• 04 Masonry — CMU, brick, stone and mortar.
• 05 Metals — structural steel, deck, framing and fabrications.
• 06 Wood, Plastics and Composites — framing, finish carpentry and millwork.
• 07 Thermal and Moisture Protection — insulation, roofing, waterproofing and sealants.
• 08 Openings — doors, windows, glazing and hardware.
• 09 Finishes — drywall, tile, flooring, ceilings and paint.
• 10 Specialties, 11 Equipment, 12 Furnishings, 13 Special Construction and 14 Conveying Equipment.

Facility services (Divisions 21–28)

• 21 Fire Suppression, 22 Plumbing and 23 HVAC.
• 25 Integrated Automation and 26 Electrical.
• 27 Communications and 28 Electronic Safety and Security.

Site and infrastructure (Divisions 31–33 and beyond)

• 31 Earthwork — excavation, grading, shoring and fill.
• 32 Exterior Improvements — paving, curbs, fencing and landscaping.
• 33 Utilities — water, sewer, storm, gas and electrical utilities.

Divisions 34–35 (transportation, waterway and marine construction) and 40–48 (process integration and power generation) apply to specialized infrastructure and industrial projects.

How estimators use divisions

• Organize the takeoff and estimate so that each specification section has a matching cost section.
• Create scope sheets and bid-leveling sheets by division or trade package.
• Check that every division in the specifications has been priced, assigned to a subcontractor or intentionally excluded.
• Compare cost per square foot by division with historical data to spot outliers.

Using divisions in a bid package

A bid package organized by CSI division makes it easy to confirm that every specification section has been priced, assigned to a subcontractor or intentionally excluded. Many bid forms and schedules of values follow the same structure. When two divisions share work — for example fire-stopping between Division 07 and Divisions 21–28 — name the responsible trade in the scope sheets.

Specification sections vs divisions

Divisions are broken into sections with six-digit numbers, such as 04 22 00 Concrete Unit Masonry. The first two digits are the division, the next two the level-two group and the last two the level-three subdivision. Sections tell you what products, standards and tests apply, and are the reference for submittals and quality control.

Estimating by division

Bid Sharp prepares takeoffs and estimates for every CSI division from 01 through 33. Browse our division and trade pages or upload your plans for a free quote.

Division numbering in practice

When a specification refers to Section 09 30 00 Tiling, the first two digits identify Division 09 Finishes. Use the full section number in scope sheets and submittal registers so each requirement can be traced to its source. For a practical overview, see our estimating FAQ and glossary.