Last reviewed . If your team tracks addenda a way this guide misses, tell us and we will add it.
The short version
Log each addendum the day it lands: number, dates, sheets, sections and the answers that change scope. Swap the superseded sheets but keep them. Re-run the takeoff it touches, tell the subs it affects, and check each quote against the log section by section. Fill the bid form’s acknowledgement from the log. Then walk every row and make sure the change reached the takeoff, the sub’s line and the proposal.
Leveling the quotes once they are current is its own job: how to catch scope gaps in sub quotes and how to build a bid leveling sheet.
Following an addendum all the way into the bid
Log every addendum the day it lands
Keep one addendum log per bid, and write each addendum into it the same day it arrives, even if you will not read it properly until tomorrow. Number, issue date, the date you received it, every sheet it reissues or adds, every spec section it changes, and the bidder questions it answers.
The log is not paperwork for its own sake. On bid day it is the only place that tells you, in one look, how many addenda exist, which trades they touched and whether each change made it into the bid. Plan rooms and email do not number things for you, and Addendum 04 has a way of arriving before Addendum 03 does.
If the addendum says it changes the bid date, the bid time or the bid form, put that at the top of the row in plain words. Those are the changes that cost you the whole bid, not a line of it.
An addendum log template. One row per addendum; the example column is a made-up Addendum 03 on a made-up job, to show a filled-in row.
| Column | What goes in it | Example row |
|---|---|---|
| No. | The addendum number as issued | 03 |
| Issued / received | Both dates. The gap between them matters on a late one | Issued Oct 13, received Oct 14 |
| Bid date, time or form | Any change to how or when you bid | No change |
| Sheets changed | Every sheet reissued or added, with revision | A-201, A-202, A-501 (rev 2) |
| Spec sections changed | Every section revised or added | 09 21 16, 09 51 13 |
| Answers to questions | The answers that change scope, in a few words | Q12: resilient channel at all Level 2 corridor walls |
| Trades affected | Who has to reprice | Drywall, acoustical ceilings |
| Subs notified | Who you told, and when | Drywall Subs A, B, C; ACT Subs D, E. Oct 14 |
| Takeoff re-run | The change in quantity | Yes. Plus 420 LF resilient channel |
| In the bid | Takeoff, sub line and proposal all match | Sub B quote predates 03. Plug carried, question sent |
Read the answers to questions as hard as the drawings
Most addenda have two halves: the revised documents, and a list of bidder questions with the architect’s answers. Estimators tend to read the sheets and skim the answers. The answers are where scope moves quietly. "Provide resilient channel at all Level 2 corridor walls" in a one-line answer is as binding as a revised wall type on A-501.
Go through each answer and ask one thing: does this change what somebody prices? If it does, write the spec section and the trade next to it in the log. An answer that changes nothing still gets logged, so you know you read it.
Replace superseded sheets, and keep the old ones
Slip the reissued sheets into your working set so every takeoff, every sub and every question runs off the current revision. Mark the old sheets superseded, with the addendum number, and move them to their own folder. Do not delete them.
You keep the old sheets because you will need to compare. A reissued sheet does not always cloud every change, and the only way to find an unclouded change is to lay the old sheet over the new one. You also need them when a sub says they priced "the drawings", and you have to work out which drawings.
Re-run the takeoff the addendum touches
For each changed sheet and section, open the takeoff that came from it and redo the affected part against the new revision. Measure the changed area, recount the changed rooms, and note the difference in the log: plus 420 LF of resilient channel, minus two door openings, a new wall type on four partitions.
Re-run, do not patch from memory. Adding "about 400 LF" by eye is how a quantity ends up right on the sheet and wrong in the estimate. If the change is too big to redo before the deadline, say so in the log and decide now whether you will plug it or qualify it.
Send the change to the subs it affects
Do not assume the subs got the addendum. Some pull documents from a plan room once and never check again. For each trade the addendum touches, send the affected subs a short note: the addendum number, the sheets and sections it changed in their scope, and a request to confirm their price includes it.
Name the change, do not just attach the PDF. "Addendum 03 adds resilient channel to Level 2 corridor walls, see A-501 rev 2 and 09 21 16" gets read. A 40-page attachment with "please review" does not. Write the date you sent it in the log.
Check which addenda each sub quote acknowledges, section by section
When a quote comes in, read the addenda line before the price. Then hold it against the log, not against a count. A sub who acknowledges Addenda 01 and 02 has not priced 03, and the question is not "how many did they miss" but "what did 03 change in their section". If 03 changed nothing they price, note it and move on. If it did, that sub is not priced for your job yet.
Watch for the quote that names no addenda at all. That is not the same as acknowledging all of them. Ask in writing, and until the answer comes back, carry the changed scope as a plug against that sub.
Acknowledge every addendum on the bid form
Most bid forms have a line or a box where you list the addenda you received, and the instructions to bidders say what happens if you leave one off. Read that clause when the bid documents first arrive, not on bid day. On many public bids an incomplete acknowledgement can be grounds to reject the bid, whatever the price.
Fill the acknowledgement from the log, not from memory or the email folder. If the form wants numbers and dates, give numbers and dates. If an addendum arrives after the form is filled out, fix the form, and check whether the addendum issued a revised form you are now supposed to use.
Trace each change into the takeoff, the sub’s line and the proposal
Before the number goes out, walk the log one row at a time. For every change, three questions: is the new quantity in the takeoff, is the sub’s line priced for it or plugged, and does the proposal say what you assumed? A change that reached the takeoff but not the sub’s line is still a gap.
Tick the last column of the log only when all three are true. Every row should end ticked, plugged or written into the proposal as a qualification. A row with nothing in the last column is a change you know about and did not bid.
Logging addenda in your inbox instead of a log
Email sorts by date received, not by number, and it does not tell you what changed. On bid day you need one list you can read top to bottom.
Skimming the answers to questions
A one-line answer can add scope as surely as a reissued sheet. Read every answer and log the ones that change what someone prices.
Throwing away the superseded sheets
You need them to find unclouded changes and to work out what a sub actually priced. Mark them superseded and keep them.
Adjusting a quantity by eye
Redo the affected part of the takeoff against the new sheet. A guessed adjustment looks fine until someone checks it.
Counting acknowledged addenda instead of reading what they changed
A sub who missed one addendum may be fine, or may be short a whole assembly. The log tells you which, section by section.
Filling the bid form from memory
Copy the acknowledgement from the log. A missed number on the form can cost you the bid, not just a line in it.
When the addendum lands the day before bid
The order above still holds, it just runs in hours instead of days. Log it first, even before you read it. Check the top of it for a change to the bid date, time or form, because that one changes everything else. Then sort the changes by size.
Small changes you re-run and get priced. For bigger ones, call the affected subs that afternoon and follow up in writing, carry your own plug for anything that will not come back in time, and write a qualification into the proposal that names the addendum and what you assumed. If the change is too big for anyone to price properly, ask the owner in writing whether the bid date will move. Do not leave it off the bid form because you could not price it all: you still received it, and the form still asks.
Questions people ask
What is an addendum in construction bidding?
A written change to the bid documents issued before bids are due. It can reissue drawings, revise spec sections, answer bidder questions, or move the bid date. Once issued it is part of the contract documents, so every bidder is expected to price it and acknowledge it on the bid form.
What happens if I forget to acknowledge an addendum on the bid form?
It depends on the instructions to bidders, so read them. On many public bids an unacknowledged addendum can make the bid non-responsive, which means it can be rejected regardless of price. Some owners will let a bidder fix a minor omission and some will not. Treat the acknowledgement line as part of the price.
Is a verbal answer at the pre-bid meeting binding?
Usually not. Most instructions to bidders say only written addenda change the documents. If something said at the pre-bid meeting changes scope, submit it as a written question so it comes back in an addendum, and do not price on the strength of what was said in the room.
Can I ask for more time when a late addendum changes a lot of scope?
You can ask, in writing, through whoever the instructions to bidders name for questions. Say which addendum, which sections, and why the scope cannot be priced properly by the current date. The owner decides, and the answer comes back as another addendum if the date moves. Until it does, plan to bid on the original date.
Do subs have to acknowledge addenda on their quotes?
Nothing forces them to, which is why you check. A sub quote that names the addenda it covers lets you see straight away whether it is current. A quote that names none, or stops early, needs a written confirmation before you carry it as complete.
Caliente Vision
Caliente Vision follows every addendum into the bid
Caliente Vision reads each addendum against the drawings, the spec, the takeoff and the sub quotes your team already has. It shows which sections and sheets the addendum changed, which quotes were priced before it, and which changes have not reached the number yet. It drafts the note to the affected subs and waits for your approval before anything is sent. Caliente Vision finds, connects and checks. Estimators decide.