Tender Addenda in Québec: Why They Change Everything

You found a call for tenders on SEAO, ordered the documents, and spent hours preparing your bid. You submit it, confident. Two days later, your bid is set aside. The reason: an addendum published the day before the closing date had changed a technical criterion. Your bid didn't account for it.

This scenario happens more often than you'd think, and it's 100% avoidable.

Why public bodies publish addenda

A call for tenders isn't set in stone once it's published. Between the notice going online and the closing date, things change:

A potential tenderer asks a question that exposes an ambiguity in the specifications. The body clarifies, by addendum. A technical drawing contained an error in the dimensions. The body corrects it, by addendum. The market shifted and the planned delivery timelines became unrealistic. The body adjusts, by addendum. A complaint filed with the body is deemed founded and leads to a change in the conditions.

The law frames this process. When an amendment is likely to affect prices, the addendum must be sent at least seven days before the deadline for receiving bids. If that timeframe can't be met, the deadline is pushed back.

What an addendum can change (and what it can't)

An addendum can touch almost anything in the tender documents: technical specifications, selection criteria, the scoring grid, deadlines, required insurance, the bid form itself.

What it can't do: fundamentally change the nature of the contract to the point that it becomes a different contract. In principle, if a municipality publishes a call for tenders for snow removal and an addendum turns it into a paving contract, that's a new call for tenders, not an addendum. (In practice, the most common addenda are technical clarifications and minor corrections, not overhauls. But the rare major addenda are the ones that do the most damage if you don't read them.)

How not to miss anything: the method

If you've ordered the documents: addenda published after your order are distributed to you automatically by SEAO, at no extra charge. That's the good news. But "distributed" doesn't mean "read." Check your email and SEAO regularly.

If you haven't ordered yet: any addenda already published when you order are included in your documents, at your expense (like the rest of the documents).

In every case: never submit your bid without checking SEAO one last time on the same day. A last-minute addendum, published in the final days before closing, is exactly the one that will get you rejected if you don't read it.

When in doubt

If an addendum is confusing or contradicts the original documents, you have the right to ask the buyer questions, the contact person is named in the tender documents. Put your question in writing before the deadline. The answer will be published as an addendum, accessible to every tenderer (in practice, the identity of whoever asked isn't disclosed).

If you believe an addendum makes the tender conditions unfair, you can file a complaint with the body or with the Autorité des marchés publics (AMP), Québec's public procurement watchdog. But do it quickly, complaint windows are short and tied to the closing date.

Sources

Act respecting contracting by public bodies (CQLR, c. C-65.1) and its regulations (addendum transmission timeframe). Système électronique d'appel d'offres (SEAO), seao.gouv.qc.ca. For the municipal sector: Cities and Towns Act (s. 573), Municipal Code (art. 935); Act respecting contracting by municipal bodies (LCOM), in force April 1, 2026.