How to Check an Addendum Against Your Bid

Why this matters

An addendum is a change to the bid documents issued while bidding is still open. Once the contract is signed it is part of the contract, which means the work it adds is base scope: you priced it, whether or not you read it. A shop that bids off the original set and misses Addendum 2 does not get paid extra later for the thermostats Addendum 2 moved into its scope. It installs them on its own hours. And a bid form that does not acknowledge every addendum by number may be treated as nonresponsive, which on a public job can mean the bid is not considered at all.

The structure of the bid set itself, and how to read scope out of it, is covered in Reading Bid Documents + Scope Reference. This card is what to do in the hour after an addendum lands, using one addendum as the running example.

The addendum

A mechanical shop is bidding the HVAC for a two-story office renovation. Its takeoff is done and its labor is carried at 240 hours. Four days before bids are due, this arrives:

ADDENDUM NO. 2              Date: 4 days before bid
Project: Office Renovation, Floors 1-2
This addendum forms part of the Contract Documents.
Acknowledge receipt on the Bid Form.

ITEM 1. DRAWINGS
  Sheet M-201, Second Floor HVAC Plan: REISSUED,
  Rev 1, dated with this addendum. Supersedes
  previous issue.
ITEM 2. SPECIFICATIONS
  Section 23 07 13 Duct Insulation, 3.2.A:
  DELETE "1-1/2 in thick" and SUBSTITUTE
  "2 in thick" for concealed supply duct.
ITEM 3. CLARIFICATION
  Question: Who furnishes and installs the
  thermostats shown on M-201?
  Answer: Thermostats are furnished and installed
  by the HVAC contractor. Delete "by controls
  contractor" from M-001 General Note 7.
ITEM 4. CLARIFICATION
  Bid date and time unchanged.

Step 1: Confirm you have every addendum, in order

Before reading Addendum 2, check that you have Addendum 1. Addenda are numbered sequentially, and plan rooms and bid portals do not always push every one to every bidder. If your file jumps from the original set to Addendum 2, call the issuer for Addendum 1 before you do anything else, because Addendum 2 may revise a sheet Addendum 1 already reissued, and you need to know which version you are comparing against.

Skip it and: you price against a sheet two revisions old while believing it is one.

Step 2: Acknowledge it on the bid form now, not at the end

Write "Addendum No. 2, received [date]" in the acknowledgment block on the bid form the day it arrives. The acknowledgment is what says your price includes it. Shops that leave acknowledgments for the final hour before submission are the ones that miss one, and missing the box can disqualify a correct price.

In the example: the estimator fills in No. 1 and No. 2 on the draft bid form, with dates, before reading further.

Step 3: List every item that touches your scope

Read the whole addendum, including items that look like another trade's, and list each one that touches yours, with what it changes. Clarifications often move work between trades, and a "general" note on a mechanical sheet is your note even when the question came from someone else.

In the example, all three substantive items touch the HVAC scope:

• Item 1 reissues M-201, the shop's own plan. Everything on it has to be re-checked.
• Item 2 thickens concealed supply duct insulation from 1-1/2 in to 2 in.
• Item 3 moves thermostats from "by controls contractor" into the HVAC scope. Read the answer, not just the question: the question asked about M-201, but the answer deletes General Note 7 on M-001, and a general note governs every mechanical sheet. The first-floor thermostats on M-101 move into the shop's scope too, though M-101 was not reissued and nothing on it is clouded.

Item 4 changes nothing. That is three items to price.

Step 4: Swap the reissued sheets, and find what moved

Pull the superseded M-201 out of the working set, mark it SUPERSEDED with the addendum number, and file it; do not throw it away, because comparing the two is how you find the change. Lay the new sheet over the old, or compare them side by side, and look first at the revision block and the revision clouds (see related: The Revision Block and Why It Decides Everything). Then check outside the clouds. Designers do not always cloud every change, and an unclouded change in a reissued sheet is still in the contract.

In the example: Rev 1 of M-201 carries one cloud: a conference room split into two rooms, adding a supply branch with two diffusers and a return grille. The estimator also finds, outside any cloud, that the thermostat count on the second floor went from 6 to 8, because the split created two new zones. That second change is the one an estimator reading only the clouds would have missed.

Step 5: Reprice each item in hours and material, separately

Price each addendum item on its own line so you can see what the addendum cost you and defend it if asked. All figures below illustrate the method.

Item 1, the new branch. 20 ft of branch duct, two diffusers, one return grille, balancing: 6.0 labor hours plus material.

Item 2, the insulation change. The concealed supply duct quantity does not change, but the thicker wrap does: more material per foot, and the installers report it goes on at nearly the same rate. The estimator carries material on the supplier's revised quote for 2 in wrap and adds 2.0 labor hours for the slower handling of the bulkier roll.

Item 3, the thermostats. These are now the shop's to furnish, mount, and wire to the units, and the bid carried none, because the original note said controls contractor. The count is 8 on the second floor per Rev 1 of M-201 plus 5 on the first floor per M-101, which is 13. At 1.5 labor hours each, 13 thermostats is 19.5 hours, plus the devices and low-voltage cable.

The total. 6.0 plus 2.0 plus 19.5 is 27.5 added labor hours. Against the 240 hours carried before the addendum, 27.5 divided by 240 is about 11.5 percent more labor.

The two ways to get item 3 wrong. An estimator who read only the clouds and the question would have counted the 6 thermostats on the superseded M-201 and stopped there: 6 at 1.5 hours is 9.0 hours against the correct 19.5, leaving 10.5 hours of the shop's own labor unpriced. One who caught the unclouded count but not the general note would have counted 8 and carried 12.0 hours, still 7.5 short. Neither miss shows up until the thermostats are on the wall.

Skip it and: you add a lump to the bid that you cannot trace, which is fine until the low bidder's price is questioned and you are asked what the addendum cost.

Step 6: Note it on the quote and the scope letter

The bid form acknowledgment says you received it. Your own quote or scope letter, especially on a sub-bid to a general contractor, should also state the documents your price is based on: "Price based on drawings and specifications dated [original], and Addenda 1 and 2." Then name the scope the addendum moved, in your inclusions: "Includes thermostats, furnished and installed, first and second floors (13), per Addendum 2 Item 3." The count in the line is deliberate: it tells the reader exactly what was priced, and it is the number someone will check against the walls later.

In the example: that line matters because the general contractor may be carrying a controls sub whose own price still includes thermostats. Naming it in the inclusions surfaces the overlap before award rather than after.

Step 7: Push questions back before the question deadline

An addendum often raises new questions. The bid documents usually set a cutoff for questions some days before bid opening, and often a last date for issuing addenda. If a change is ambiguous, send the question before that cutoff, through the channel the instructions to bidders name, not by phone to a friendly engineer.

In the example: the estimator asks whether the two new thermostats are on the same network as the base units or stand-alone, because the answer moves wiring hours. The answer arrives as Addendum 3, two days later, and the process restarts at step 1.

What changes the answer

• An addendum after you submitted. Some jurisdictions and owners allow a bidder to modify or withdraw a bid until opening; some do not. If one arrives after you submitted, read the instructions to bidders immediately for whether you may revise, and do it in the form they require. This is not legal advice; on a public bid with real exposure, ask counsel.
• A sub-bid with a different set. A general contractor's invitation to bid may list documents through Addendum 1 while the owner has issued 2. Price to the newest set and say so; your scope letter names which.
• A bid alternate. An addendum that adds or revises an alternate (a priced option the owner may accept or not) is priced on the alternate line of the bid form, not in the base bid. Folding it into the base raises the number the owner compares against bidders who kept it separate, and if the owner declines the alternate, the shop has bid work it will not do.
• A deductive change. An addendum that removes work is priced the same way, as a credit, line by line, and the same unclouded-change check applies.

References

• See related: Reading Bid Documents + Scope Reference
• See related: The Paper That Changes a Job: RFI to Change Order
• See related: The Revision Block and Why It Decides Everything
• See related: How to Check Your Scope Against By Others and NIC Notes
• Trade-standard bidding practice; the project's instructions to bidders and bid form govern acknowledgment and question deadlines