You've got three bids sitting on your desk. Maybe four. They all look reasonable at first glance — the numbers are in the same ballpark, the scope descriptions sound similar, and the contractors all came recommended.
So you pick the lowest price and move on. You've got 14 other things to deal with today.
Six weeks later, you're staring at a change order that wipes out the savings you thought you were getting. Sound familiar?
Here's the thing — most bad bids don't look bad. The problems are hiding in the details that nobody has time to read line by line. But if you know what to look for, you can spot them in minutes instead of finding out the hard way on the job site.
These are the five red flags that show up over and over again in subcontractor bids. Miss even one of them, and it could cost you thousands.
1. Vague Scope Descriptions That Leave Room for "That Wasn't Included"
This is the most common one, and it's the most expensive.
A bid says "Install kitchen cabinets — $8,400." That sounds straightforward. But does it include demolition of the existing cabinets? What about disposal? Does it cover the hardware, or just the boxes? Is trim and filler included, or is that going to show up as an add-on?
When a line item is vague, it's not necessarily because the sub is trying to hide something. Sometimes they're just sloppy with their paperwork. But the result is the same either way — you're going to get a change order for everything that wasn't spelled out.
What to look for
Compare the scope descriptions across all your bids for the same work. If one sub lists 12 specific items and another describes the same work in one sentence, that one-sentence bid is almost certainly missing things. The more detailed bid is telling you what the complete scope actually looks like.
The fix
Before you award, ask the vague bidder to itemize. If they can't or won't break it down, that tells you something too.
2. Missing Line Items That Other Bids Include
This one is subtle because you won't notice it unless you're comparing bids side by side at the line-item level. And let's be honest — most of us aren't doing that in a spreadsheet at 9 PM.
Here's a real example. You get three bids for a bathroom remodel. Two of them include a line item for "temporary plumbing protection during demo." The third one doesn't mention it at all. Is the third bid cheaper because they're more efficient? Or is it cheaper because they're going to hand you a change order when they realize they need to protect the plumbing?
Nine times out of ten, it's the change order.
What to look for
Line up the bids by category and look for items that appear in two bids but not the third. Those scope gaps are where the change orders live. Common ones include: permits, debris hauling, temporary utilities, final cleanup, and warranty documentation.
The fix
Create a simple checklist of items you expect in every bid for that trade. If a bid is missing something from the checklist, ask about it before you sign.
3. Pricing That's Way Below Market Rate for Your Area
A bid that comes in 30-40% below the others isn't a deal. It's a warning.
There are really only three explanations for a price that's dramatically below market. One, the sub made a math error and they're going to figure it out midway through the job. Two, they're cutting corners on materials or labor. Three, they're desperate for work, which means they might not have the cash flow to finish yours.
None of those are good outcomes for you.
This doesn't mean you should always take the highest bid either. But if you know what the going rate is for, say, an electrical rough-in or a 2,500 square foot roofing job in your area, and one bid comes in at half that price, something is off.
What to look for
Know the ballpark market rate for the trades you're bidding. If a bid is more than 20% below the average of the other bids, dig into why. Ask the sub to explain their pricing — a legitimate low bidder can tell you exactly why they're cheaper (bulk material pricing, lower overhead, faster crew, etc.).
Let AI catch these red flags for you
Upload your subcontractor bids and EstimateHawk flags scope gaps, missing items, and pricing outliers automatically — in about 30 seconds.
Run your first comparison — $49The fix
Track your actual project costs over time and build your own sense of what things should cost in your market. Or use a tool that compares bid pricing against market data automatically.
4. No Timeline or Unrealistic Duration Estimates
A bid that doesn't include a timeline is a bid that has no accountability.
If a sub can't tell you when they'll start and how long the work will take, they're either too busy to commit, too disorganized to plan, or intentionally keeping it vague so they can juggle your project with three others.
Almost as bad: a timeline that's unrealistically short. If every other sub says a kitchen remodel takes 3-4 weeks and one says they'll do it in 8 days, they're either lying to win the bid or they're planning to cut corners.
What to look for
Every bid should include a start date (or "X days from notice to proceed"), estimated duration, and any scheduling dependencies ("must follow completion of electrical rough-in"). If these are missing, the sub hasn't thought through the logistics.
The fix
Make timeline specifics a requirement in your bid requests. If a sub can't commit to a schedule, they shouldn't get the job.
5. No Insurance, Licensing, or Warranty Documentation
This one should be obvious, but it still happens all the time. You get a great price from a sub who "forgot" to include their insurance certificate. Or their license is from a different state. Or their warranty is one sentence that says "workmanship guaranteed."
Hiring an uninsured or unlicensed sub doesn't just put the project at risk — it puts you at risk. If something goes wrong, you're the one the homeowner is coming after. Your insurance rates go up. Your reputation takes the hit.
What to look for
Every bid package should include current general liability insurance (minimum $1M), workers' comp coverage, a valid contractor's license for your state, and a written warranty with specific terms and duration.
The fix
Don't even evaluate a bid that's missing these documents. Make it a hard requirement. Any sub who pushes back on providing insurance certs isn't someone you want on your job site.
The Bigger Picture
Here's what all five of these red flags have in common: you can only catch them if you're actually comparing bids in detail. Not just looking at the bottom-line number. Not just scanning the first page. Actually lining up the scope, the pricing, the inclusions, and the documentation side by side.
Most GCs don't do this because it takes hours. You've got projects to run, subs to coordinate, clients to manage. Sitting down with a spreadsheet to compare 47 line items across three bids isn't how you want to spend your Tuesday night.
That's why we built EstimateHawk. Upload your bids as PDFs, and the AI extracts every line item, normalizes the pricing, flags the scope gaps, and compares everything side by side — in about 30 seconds. It catches the red flags so you don't have to find them the expensive way.
Quick Reference: The 5 Red Flags Checklist
Before you sign your next subcontractor agreement, check for:
If you check all five, you're ahead of 90% of GCs out there.