How Do You Bid a GC's Job as a Subcontractor?

Knowing what the general contractor does with your number tells you how to write it. On bid day the GC's estimator collects every bid for your trade and levels them: each bid is read against one list of scope items, and anything you excluded gets a plug, the GC's own estimate of its cost. The leveled totals are compared, the apparent low bidder is asked to confirm its scope, and the winning number goes into the GC's own bid to the owner.

On some public jobs this is written into the rules. One North Carolina construction manager-at-risk contract has trade bids opened publicly, tabulated, and the apparent low bidder's documentation reviewed to verify its scope; a bid that failed to account for all the costs of its scope may be disqualified, and the package goes to the lowest verified bid (NC State University, CM-at-Risk General Provisions). Private GCs are not bound by those rules, but the comparison works the same way.

Every bid costs estimating time, so choose. Get on the bid lists of the GCs you want to work for (GCs keep lists of subs by trade and invite from them), then judge each invitation before you price it.

If the answer is no, decline promptly. A GC who knows early can invite someone else, and remembers that you told it.

• Read the scope items the GC lists. They are the rows your bid will be compared on.
• Check the drawing set date, the specification sections for your trade, and the addenda issued so far.
• Note what the GC says is not in your package, and look for boundary items it did not mention: firestopping, blocking, cutting and patching, equipment connections, temporary work.
• Walk the site if a walk is offered. Conditions you have seen are conditions you can price.
• Ask questions in writing before the questions deadline. The answer goes to every bidder, so it is also how you find out what others asked.

The job is fictional: "Coyle Avenue Office", a three-story office. A fictional electrical contractor prices the GC's electrical package from its own takeoff.

The contractor then breaks the $309,700 out across the GC's eight scope items, prices the two alternates separately, and gives the bond as its own add as its surety quoted it, so the GC can level the bid without guessing. The rates and percentages here are an example, not a benchmark: use your own labor rates, overhead and margin.

1. Answer in the GC's format. If it asks for a breakout per scope item, give one; it is the difference between your number and the GC's plug.
2. Price exclusions instead of only listing them where you can. An unpriced exclusion gets the GC's number. See how to write a sub proposal a GC can level.
3. Acknowledge every addendum by number. On federal sealed bids, a failure to acknowledge an amendment can be waived only when the bid clearly shows the bidder received it or the amendment has no more than a negligible effect on price, quantity, quality or delivery (FAR 14.405).
4. Meet the bond requirement. On federal prime contracts, a bid guarantee is required whenever a performance bond or a performance and payment bond is required (FAR 28.101-1), and it is at least 20% of the bid price, up to $3 million (FAR 28.101-2). A GC's requirement for its subs is set in its own invitation; check it and your subcontract.
5. Submit before the due time, in the time zone stated. A late bid is easy to refuse.

After bid day, expect a scope review call if you are low. Confirm in writing what you included, and price anything the GC thinks is missing. If you are not low, ask where you were; some GCs will tell you.

When a general contractor invites you to a trade bid in Conflo, the email links to the invitation; if you are not on Conflo yet, the link sets up a free account. Your Bids page lists every invitation sent to your company, from every GC, with tabs for needs your bid, waiting on a result, won, not awarded and passed on.

On the invitation you tell the GC whether you will bid or decline, read the scope, scope items and alternates, ask questions (answers go to every bidder without your name), and acknowledge each trade addendum before you can submit. The bid itself is a base bid, each scope item marked included or excluded with an optional breakout, alternates, exclusions and qualifications. You can revise it until bids close, and you see whether you were awarded. Conflo does not do your takeoff or price your work; you bring the number.

Winning sub bids is selective bidding plus clear answers: the right jobs, priced from the GC's scope items, with every exclusion priced or explained and every addendum acknowledged.

The GC will level your number either way. Give it your breakouts and it uses your prices; leave gaps and it uses its own.

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1. Section II, General Provisions (Construction Manager-at-Risk), part 3, Principal Trade & Specialty Contracts — NC State University Facilities. Read October 16, 2026.
2. FAR 14.405, Minor informalities or irregularities in bids — Acquisition.gov, U.S. General Services Administration. Read October 16, 2026.
3. FAR 28.101-1, Policy on use (Bid guarantees) — Acquisition.gov, U.S. General Services Administration. Read October 16, 2026.
4. FAR 28.101-2, Solicitation provision or contract clause (Bid guarantees) — Acquisition.gov, U.S. General Services Administration. Read October 16, 2026.