Addenda and revisions in a steel bid

Why addenda cost steel bidders money

Steel bids are built from a member list tied to specific sheets. When an addendum revises those sheets, three things can go wrong:

1. A change is missed. Usually it's not clouded, or it's on a sheet you didn't think applied to steel.
2. A change is double counted. The old row stays in the estimate next to the new one.
3. The whole estimate gets reworked. Hours spent re-walking the full set on bid day are hours not spent on pricing and scope.

A disciplined addendum process avoids all three.

Know the timing rules

Under AIA A701-2018 Instructions to Bidders, the standard many private bids use, bidders submit questions in writing at least seven days before bids are due, and addenda are issued no later than four days before, except an addendum that withdraws the request for bids or postpones the bid date. Bidders must acknowledge every addendum in the bid. Public owners have their own procurement rules, and many project manuals change these timings. Read the instructions to bidders on every job and put the question deadline on your calendar.

In practice, GCs and owners often issue late addenda anyway, and subcontractor bids are due to the GC before the GC's own deadline. Plan for that.

A five-step addendum workflow

1. Log it. Record the addendum number, date and time received, and every sheet and spec section it lists. Check the sheet index, since new sheets sometimes appear without being listed in the narrative.
2. Read the narrative and the Q&A. Answers to other bidders' questions often change scope ("misc. supports at RTUs are by Division 05").
3. Overlay revised sheets. In Bluebeam Revu, Overlay Pages puts the old and new sheets on top of each other in different colors, so unclouded changes show up. Do this for every revised structural sheet and for architectural sheets that carry misc. metals.
4. Find and update affected rows. Filter your takeoff by sheet and grid. Change quantities and tag each changed row with the addendum number, keeping the old value visible.
5. Reprice, log the delta and acknowledge. Update pricing, update proposal assumptions and acknowledge the addendum on the bid form.

What to check beyond the clouds

• General notes. A revised note on S-001 can change bolt types, connection design responsibility, galvanizing or camber across the whole job.
• Specifications. A change to 05 12 00 can add AESS, change the paint system or delegate connection design.
• Schedules. Column and beam schedules are often reissued in full. Overlay them.
• Details. A revised typical detail applies "where occurs" across every location.
• Architectural sheets. New canopies, screens, lintels, railings or roof frames.
• MEP sheets. New equipment supports or dunnage.

Example: pricing one addendum

Addendum 2 revises S-201 and S-202: four beams go from W16x26 to W18x35, each 30 ft long, and two new moment connections appear at grid C.

Material delta  = (35 − 26) lb/ft × 30 ft × 4 beams = 1,080 lb ≈ 0.54 tons
Connection delta = 2 moment connections (plates, welds, UT) – price from your connection unit costs
Shop delta       = minor on beams (same piece count); moment connections add fit-up and welding hours
Erection delta   = field welding and inspection at 2 connections; picks unchanged

The tonnage change is small. The moment connections are where the money is. Pricing only the 0.54 tons would miss most of the cost.

Keep an addendum log in the bid file

Addendum	Sheet / section	Change	Rows	Effect
2	S-201	W16x26 → W18x35 at grid C	44–46	+0.54 tons
2	S-202	2 new moment connections at C/4, C/5	new 210–211	+ connection, shop, field weld
2	A-501	New canopy at entry	new 212–218	+1.2 tons misc.
3	05 50 00	Galvanize exterior lintels	300–318	Finish change

Illustrative. A log like this does three things. It proves which addenda your price includes, it lets the GC level your bid against others quickly, and after award it gives the project manager the history behind each number.

Prioritize when time is short

If an addendum lands the day before bid, sort its changes by price impact:

1. Member size changes and added framing.
2. Changes to connection design responsibility, AESS, galvanizing or other spec items that hit the whole job.
3. New misc. metals items.
4. Note changes and minor dimension revisions.

Price the first two groups. Qualify the rest in writing: "Addendum 4 received [date, time]. Price includes items 1 to 6. Items 7 to 9 are excluded and will be priced on request." Never leave an addendum unacknowledged. On many public bids, a missing acknowledgment makes the bid non-responsive.

Common traps

• Updating the plan but not the schedule, or the other way round.
• Leaving the superseded row in the estimate.
• Missing a new sheet because it wasn't in the narrative.
• Treating a revised general note as "no steel change."
• Forgetting erection effects: added pieces mean added picks.

After award: revisions become changes

Once the contract is signed, revisions usually arrive as bulletins, ASIs or change order requests rather than addenda. AISC 303 addresses revisions to contract documents and how they're handled once approval documents are in progress. The same discipline applies, but now each change is priced as a change order, and the bid-stage addendum log is the baseline. If your takeoff rows are tied to sheets and revisions, the before-and-after is easy to prove.

Where RenderDraw fits

Finding which takeoff rows a revised sheet affects is the slow part of addendum work. RenderDraw keeps each proposed quantity tied to the sheet and location it came from, so you can go straight to the rows on changed sheets and recheck them. Pricing and qualifications stay with you.