The Difference Between the 16 Division CSI MasterFormat and the 50 Division Version

The Construction Specifications Institute (CSI) is the founding institution for organizing and coding specifications related to construction projects. The CSI MasterFormat, which is often referred to as the “Dewey Decimal System” of construction, is the guiding numbering system to create consistency and organization across the industry.

Among the primary advantages of having a single organization system is that it enables improved communication among project stakeholders, it makes finding and organizing construction documents much simpler, and it allows project owners to more easily compare bids from multiple contractors.


A Short History of the CSI MasterFormat

Originally founded in 1948 in the years immediately following World War II, the CSI set to work organizing and categorizing construction specifications into a numbering system. As more advanced construction materials and methods became available, it became necessary to create consistency and organization across all construction projects. The first CSI Format for Construction Specifications was published in 1963, and it contained 16 major divisions of work.

In the decades that followed, updates were made to the MasterFormat as needed, and in 2004, the CSI MasterFormat officially expanded from 16 divisions to 50 divisions. Continued innovations and expansion to the broader construction industry necessitated the growth.

The last publication to include 16 divisions was published in the 1995 MasterFormat edition. It included the following divisions:


  • Division 01 — General Requirement
  • Division 02 — Site Construction
  • Division 03 — Concrete
  • Division 04 — Masonry
  • Division 05 — Metals
  • Division 06 — Wood and Plastics
  • Division 07 — Thermal and Moisture Protection
  • Division 08 — Doors and Windows
  • Division 09 — Finishes
  • Division 10 — Specialties
  • Division 11 — Equipment
  • Division 12 — Furnishings
  • Division 13 — Special Construction
  • Division 14 — Conveying Systems
  • Division 15 — Mechanical/Plumbing
  • Division 16 — Electrical
  • Division 17 — Other – All MasterFormat related specifications nonconforming to the above CSI sections


For a comparison of what is included in the more expansive 50 divisions today, refer to our other blog post on “CSI MasterFormat: Basic Overview to Understand the Bid”. As always, if you have questions, please don’t hesitate to get in touch.

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