AEC definitions
Supplementary conditions are the project-specific amendments to the general conditions. They change insurance limits, retainage, notice periods, liquidated damages, and dispute resolution for this job. Where they conflict with the printed general conditions, the supplements control.
Definition
AIA publishes a guide for supplementary conditions because editing A201 in the margin is how clauses get broken. A clean supplement cites the article it changes and prints the revised text. Special conditions and supplementary conditions are often the same idea. Some owners use special conditions for site rules and supplementary conditions for legal edits. The label matters less than whether the document is incorporated into the agreement. Bidders who price from an unamended A201 have not priced the contract.
In depth
A supplement that says 'delete the arbitration clause' without a section number invites an argument about what else went with it. Quote the deletion and the replacement.
Do not retype the entire A201 with silent edits. A redline or a section-by-section supplement is how reviewers see the deal.
Insurance limits and additional insureds, retainage percent, the claim notice window, liquidated damages, electronic documents, and whether the architect's decision is final. Local law may require some of these changes.
Wage, tax, and prompt-payment statutes beat a supplement that ignores them. The supplement should follow the law, not fight it in a footnote.
If the supplement gives 21 days for a claim and Division 01 gives 7 for the same notice, the contractor will pick the longer one and the owner the shorter. Edit them as a pair.
Temporary facilities in Division 01 and insurance in the supplements are different subjects. Do not hide a legal change in a specification section nobody's counsel reads.
Supplementary conditions are not a surprise at contract signing. They are bid documents. A bidder who qualifies the bid against a supplement may be nonresponsive.
Addenda can revise the supplements during bidding. Acknowledge the addendum.
Subcontracts should attach the supplements that apply, not an outdated draft.
A sub who never received the liquidated-damages supplement will still meet the prime's argument that flow-down was incorporated by reference, or they will not, depending on the subcontract. Attach the pages.
Examples
A supplement replaces A201's insurance article with the owner's limits and additional-insured wording. The agreement lists the supplement.
Retainage is 5 percent by supplement, not the worksheet someone remembered from the last job.
Division 01's claim procedure is edited so the number of days matches the supplement.
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