What is an addendum in bidding?

What an addendum in bidding can change

Addenda are numbered in order, and a later one can change an earlier one. Changes made after the contract is signed are handled by change order instead. An addendum can revise any of these:

• Drawing sheets, revised or added, usually reissued under the same sheet number with a revision mark.
• Specification sections, such as a pavement thickness or a material.
• The bid form itself: items added, deleted or given new quantities.
• Scope, through answers to questions bidders asked.
• The bid date, time or delivery location.

Acknowledge each addendum on the bid form

Bid forms commonly include a place to list each addendum number and the date it was received, and leaving one off can get a bid rejected. On federal sealed bids, FAR 52.214-3 requires bidders to acknowledge every amendment, the federal term for an addendum, by signing it, listing it on the bid form or by letter, and the acknowledgment must arrive by the bid deadline. FAR 14.405 allows a missing acknowledgment to be waived only in narrow cases, such as an amendment with no more than a negligible effect on price, quantity, quality or delivery.

State and local owners set their own rules in the instructions to bidders, so read that section for each project.

What to re-check in the takeoff after an addendum

1. 1

   List every sheet and specification section the addendum reissues or changes.

2. 2

   Replace superseded sheets in your working set and mark the old ones so they are not measured again.

3. 3

   Compare each revised sheet with the one it replaces, looking for moved boundaries, new structures and changed callouts.

4. 4

   Re-measure the affected items and update any depth, thickness or material the specifications changed.

5. 5

   Remove the takeoff on superseded sheets so nothing is counted twice, then reconcile the totals with the revised bid form.

Compare addendum sheets in Zip Takeoff

When you add an addendum PDF to a Zip Takeoff project, each new sheet is matched to the older sheet with the same sheet number, such as C-5, and the old one is marked Superseded. Compare overlays the pair: red was removed, cyan was added, black is unchanged. Copy takeoff to replacement brings the old takeoff across at the same coordinates, so you edit the shapes the revision moved, then delete the superseded sheet or its takeoff.

Matching uses sheet numbers only, written as letters, a hyphen and digits, so check sheet names after adding the addendum.