When a GC levels bids, three subs’ numbers get lined up side by side — and the low number wins arguments it shouldn’t if nobody can tell what’s in it. The proposal you send is not just a price; it’s the definition of what that price buys. A tight scope letter is how you avoid winning a job you never actually bid.

The short version

  • The proposal defines the deal: state inclusions by spec section and drawing set, and state exclusions explicitly — silence reads as “included.”
  • Acknowledge every addendum by number. An un-acknowledged addendum makes your bid non-responsive on public work and a target for “you missed it, you own it” on private work.
  • Qualify the commercial terms: bid validity period, escalation assumptions, payment terms, and what happens to unit prices if quantities move.
  • On California public work, the subcontractor listing law protects listed subs from post-award substitution and bid shopping — being listed is a legal position, not a courtesy.
  • Send the scope letter with the number, every time — a price without a scope letter is an invitation to define your scope for you.

Inclusions: define the work in the bid documents’ language

Tie your scope to the documents, not to trade shorthand. “Division 9 acoustical ceilings per drawings A-601 through A-605, spec section 09 51 13, Addenda 1–3” survives bid leveling; “ceilings complete” does not. State the drawing set and date you priced — if the GC levels your bid against a newer set, the delta is a change, and your scope letter is what proves it.

List the things adjacent trades fight about, in whichever direction you priced them: hoisting, layout, fire-caulking your own penetrations, cleanup, temporary protection. Every trade has its five classic scope-gap fights; name yours.

Exclusions: if you didn’t price it, say so

The exclusions list is the highest-value paragraph in the proposal. GCs read silence as inclusion, and on bid day a leveling sheet fills unmarked boxes in your column with “assumed included.” Typical candidates, depending on trade: design/engineering, permits and fees, bonds (priced as an add), sales tax treatment, overtime and shift work, winter conditions, unforeseen conditions, hazardous materials, painting/patching by others, commissioning support beyond a stated number of visits.

Two disciplines make the list credible. First, keep it current — an exclusions list copied from job to job accumulates items that contradict the drawings you’re bidding, and one visible contradiction lets a GC argue the whole list is boilerplate. Second, exclude by item, not by blanket (“anything not expressly included is excluded” reads as unserious and gets ignored).

Qualifications: the commercial fine print that saves you later

  • Bid validity. State how long the number holds — 30, 60, 90 days. In a volatile material market, an open-ended number is a free option you’re writing the GC.
  • Escalation. If your price assumes buying major material within a window, say so.
  • Alternates and unit prices. Price alternates as discrete adds/deducts against a defined base bid. For unit prices, state the assumed quantity range — a unit price that’s fair at 100 units may be ruinous at 10.
  • Payment terms. Progress payments, retention you’ll accept, and stored-material billing. You won’t win every term, but stating them establishes what you priced.
  • Schedule assumptions. Duration, sequence, and mobilizations included. The cheapest crew is one continuous mobilization; if the GC’s schedule implies four, your letter should say what number five costs.

Addenda: the responsiveness trap

Track every addendum against every open bid and acknowledge them by number in the proposal. On public work, failing to acknowledge a material addendum can make the bid non-responsive — disqualified regardless of price. On private work the failure mode is quieter: the GC assumes addendum scope is in your number, and post-award you’re arguing about who owns work you never saw. A simple addendum log per pursuit — received, reviewed, priced, acknowledged — closes the gap.

California public work: the listing law is your leverage

On most California public projects, the GC must list the subcontractors performing work above a small threshold of the total bid — and once listed, you can’t be swapped out or your price shopped down except through a formal substitution process with notice, cause, and a right to object. That’s the Subletting and Subcontracting Fair Practices Act, and it exists precisely because bid shopping and bid peddling were endemic. What it means in practice: getting listed in the GC’s bid is a legal position worth protecting. Confirm you were listed, keep the bid-day paper (your proposal, the time it was sent, who confirmed receipt), and if a GC tries to resolicit your scope after award, know that the burden is on them.

Send the letter with the number — always

The bid-day temptation is to phone in the number at deadline and “paper it later.” Later never comes, and the GC’s leveling sheet — not your proposal — becomes the record of what you bid. Even under deadline pressure, a one-page scope letter with inclusions, exclusions, addenda acknowledged, and validity period beats a naked number. The shops that win profitable work treat the proposal as the first contract document of the job — because that’s exactly how the GC’s lawyers will treat it.