Red Flags in a Sub Bid That Signal Change Orders Are Coming

The number looks clean. It’s on a letterhead, it covers the right scope, and it landed two hours before deadline. But the number is not the bid. The pages behind it are the bid. Most estimators know this and still don’t read them the way they should, because bid day is moving fast and the math checks out. That’s exactly when a sub counts on you not looking.

Here are the specific red flags to find before you make the call, not after.

Allowances Without a Stated Assumption

An allowance line is a sub telling you they don’t know what something costs, but they’re putting a number in anyway so their total looks complete. That’s not a problem by itself. The problem is when the allowance has no backup: no unit cost, no quantity, no stated assumption. “Electrical gear allowance: $45,000” without a panel schedule reference or a listed amperage assumption is a placeholder, not a price.

When you plug that into your GMP and the gear lands at $72,000, the sub will pull out the proposal and show you the allowance language. They’re right to. You accepted it. The fix is to call every allowance line before you use the number and get the assumption documented in writing, if the sub can’t explain the basis in two sentences, the allowance is a guess dressed up as a number.

Exclusions That Hand You the Risk

Page three of most sub proposals is where the real negotiation happens, and most estimators skim it. The carve-outs to look for:

“All work assumes clean backfill” or “assumes no rock.” On a site with unknown subsurface conditions, this is the sub handing you the risk. If rock shows up, the change order is already written.

“Permit fees by owner” or “permit fees excluded.” On a $2.4M mechanical scope, permit fees can run $15,000 to $40,000 depending on jurisdiction. If that’s excluded from every sub and excluded from your Gen Conditions estimate, someone is carrying it in contingency, or no one is.

“Existing conditions to be verified by GC.” This one shows up in renovation and TI work constantly. It means if they open the wall and the conditions don’t match the drawings, the delta is yours. That’s a reasonable position from the sub’s perspective, but you need to know you’re holding it before you submit.

“Lead times TBD / pricing subject to material availability.” This is the exclusion that becomes a six-week delay conversation at the 30% submittal meeting. Get a hard lead time commitment before award, or at minimum before GMP.

What Isn’t in the Proposal

What’s not in the proposal is usually more dangerous than what is. Compare the bid against the spec section and the drawings. If the sub is doing HVAC on a lab project and the proposal doesn’t mention TAB (testing, adjusting, and balancing), either they’re planning to add it later or they assumed someone else is doing it. Same goes for insulation on a plumbing bid, fire stopping on a framing scope, or commissioning on a controls package.

The ASA has written about this pattern from the subcontractor side: scope gaps on bid day often come from incomplete documents, not from bad faith. That’s worth remembering when you’re reading the proposal. But incomplete documents cut both ways, and the gap still ends up in a change order regardless of who caused it.

Qualifications That Quietly Redefine the Scope

Some subs include a qualifications section that redefines what they’re actually pricing. “Price based on single mobilization,” “assumes work will proceed without interruption,” “staging area to be provided by GC”, these are scope qualifiers that affect execution and cost. If your project has a phased interior build-out or a constrained site, “single mobilization” is not how the job runs. That delta comes back as a change order for every re-mobilization.

Read the qualifications section like a contract, because that’s what it becomes. The sub’s bid is their offer. When you cut the PO, you’re accepting those terms unless you explicitly carve them out in the subcontract.

The Number That’s Dramatically Low

This one gets overlooked because the instinct when a number is low is relief, not suspicion. That instinct is wrong. A sub who is $180,000 under the next bidder on a mechanical scope either knows something the others don’t, missed something significant, or is buying the work with the intention of recovering margin through changes. All three of those scenarios require a conversation before award, not after.

As covered in how to scope out subcontractor exclusions before they blow up your budget during buyout, the low number is an argument. The exclusions page is where they make it. Read both together before you decide what you actually have.

Comms Center keeps every sub proposal, email thread, and scope clarification attached to the bid record, so when you’re reviewing a number two weeks after it arrived, the full context is there. No inbox archaeology, no missing attachments. See how it works at commscenter.com.