CSI MasterFormat
CSI MasterFormat is the standard numbering system that organizes construction specifications into numbered divisions and sections.
Also written as MasterFormat, CSI divisions, CSI.
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Reviewed by Eric Collin · President and Founder of Firmo Construction, 20+ years in preconstruction and bid evaluation
It is published by the Construction Specifications Institute together with Construction Specifications Canada, and it is the reason a specification section number means the same thing from one project to the next.
The current structure runs from Division 00 through the 40s, with a substantial number of division numbers reserved for future use rather than in active service. Familiar ones include Division 03 for concrete, Division 23 for heating, ventilating and air conditioning, and Division 26 for electrical. Below the division, sections carry six-digit numbers that identify progressively narrower scope.
Its practical value in bidding is a shared vocabulary. When packages, specifications, and cost codes all use the same numbering, a line in a bid can be traced to a section in the specification without anyone having to interpret what a bidder meant by a trade name.
It is worth noting that division boundaries do not always match how work is actually bought — local market practice splits and combines trades in ways MasterFormat does not — so package structure follows it loosely rather than strictly.
- Bid package
A bid package is the bundle of scope issued to subcontractors as a single unit for pricing, usually corresponding to one trade.
- Scope of work
A scope of work is the written definition of what a package or contract covers — the work a bidder is being asked to price.
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