A Missed Addendum, an Incomplete Masonry Quote, and a Steel Unit Price
Bid day for a 62,000 sf three-story steel-framed office is 48 hours away. Your estimator took off 410 tons of structural steel and 38,000 sf of deck from the drawings. Addendum No. 3, issued two days ago, changes beam sizes at levels 2 and 3, adding about 35 tons of steel and 1,200 sf of deck, and revises the penthouse from masonry to steel stud. The estimator missed the addendum. The masonry subcontractor's quote expressly excludes loose lintels, through-wall flashing, and sealant at shelf angles. The mechanical quote includes a 10% contingency and states that temperature controls are by others. The bid form requires a lump sum, a steel unit price per ton, and an additive alternate for a 4,000 sf penthouse. Your markup is 2%. The owner's purchasing policy awards to the lowest responsive bidder and does not allow post-bid negotiations. Your base number is already within 1.5% of the nearest competitor. You must decide what to carry, how to use the unit price, and what to disclose.
1. Reconstruct the steel scope and determine what to carry for the addendum.
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The addendum changes the base scope. Start with the original takeoff of 410 tons and add the 35 tons of revised beams, for 445 tons. Add 1,200 sf of deck to the original 38,000 sf, for 39,200 sf. Using buy-out assumptions of $3,400 per ton furnished and erected and $2.75 per sf for deck:
- Added steel: 35 tons × $3,400 = $119,000
- Added deck: 1,200 sf × $2.75 = $3,300
- Direct add: $122,300
- With 2% markup: $122,300 × 1.02 = $124,746
Carry the corrected quantity, not the original 410 tons. Do not inflate the steel unit price to recover the mistake; the bid form makes unit prices govern quantity changes, and an inflated price can make the bid materially unbalanced. Enter a realistic unit price such as $3,400 per ton. If the addendum is unclear, issue an RFI before bid; after opening, a verbal clarification is not reliable.
2. How should you treat the masonry exclusions and the mechanical contingency?
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The masonry quote is not a complete scope. Loose lintels over openings, through-wall flashing, and sealant at shelf angles are required for a complete masonry assembly under the specifications and normal masonry detailing. Price them explicitly, either by getting a revised quote before bid or by adding a documented allowance. Do not assume the masonry sub will absorb them; if it refuses later, you own the gap.
The mechanical quote's 10% contingency is already inside the sub's price. Do not add a second 10% contingency on top of it. Instead, verify scope: the quote says temperature controls are by others, so price controls separately if they are in your contract. Also confirm testing, adjusting, and balancing, controls integration, and permits. Apply your 2% markup once to the buy-out, not to a duplicate contingency.
On the penthouse alternate, perform a separate takeoff for the steel-stud revision. Do not use the base steel unit price as a substitute for a real alternate scope, because the alternate includes different framing, sheathing, and finishes.
3. What are the risks of an unbalanced bid or a post-bid correction, and what should you do before submission?
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Front-loading the bid-such as inflating the steel unit price or the early-mobilization items-can be rejected as materially unbalanced, especially where the owner must award to the lowest responsive bidder and cannot negotiate. It also backfires if steel quantities decrease: the owner may use the unit price as a credit. A unit price should be a reasonable estimate of the work, not a claim-recovery tool.
After bid opening, relief for a unilateral estimating mistake is limited. The owner may hold the bid, require the work at the bid price, or allow withdrawal only under narrow rules; a bid bond may be at risk. Notify the owner immediately in writing if the mistake is clerical and evident from the bid documents, but do not assume you can correct the number or renegotiate.
The safe course is to correct the estimate before submission: include Addendum No. 3, add the masonry scope gaps, price the controls, and verify the penthouse alternate. If the corrected number is not competitive, that is better than winning a contract that is $120,000 short.