Supplemental instruction

EstablishedSIASI

Also: Site instruction

An instruction from the consultant — usually drawings, specifications or a written note — that clarifies or adds detail to the work without changing the contract price or contract time.

Explanation

In CCDC 2 (2020) a Supplemental Instruction must be consistent with the intent of the Contract Documents and carries no adjustment to Contract Price or Contract Time. If the contractor believes an instruction does affect price or time, it should notify the consultant before proceeding, so the instruction can be handled as a Change directive or Change order. Many RFI responses are issued as supplemental instructions. In AIA practice the comparable instruments are minor changes in the work (A201 §7.4) and the architect's supplemental instructions form.

Practical example

SI-021 issues a revised detail for a stair handrail bracket to suit the selected wall finish. The contractor confirms there is no cost or schedule impact and proceeds.

Why it matters

Using the correct instrument avoids disputes later about whether extra cost was authorised.

Common confusion

Standards and references

  1. CCDC 2 2020 — CCDC 2 – 2020 Stipulated Price Contract. Canadian Construction Documents Committee (CCDC), 2020. Definitions.Original VDC Stack.io wording, based on the standard
    Supports: Supplemental Instruction definition: clarifying instruction consistent with contract intent, no change in price or time · Status: Definitions and GC numbering reviewed from a copy included in a public tender package; confirm against a licensed copy.

VDC Stack.io writes its own explanations and does not reproduce copyrighted standards text. Consult the cited standard for normative wording.

Cite this entry

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VDC Stack.io. (2026). Supplemental instruction. In VDC Stack.io Knowledge Dictionary. Retrieved from https://vdcstack.io/dictionary/supplemental-instruction/