How to Review a Construction Bid: Owner's Checklist

Low bid doesn't mean best bid. The lowest number on a bid leveling sheet often signals missing scope — work the GC didn't price because they didn't find it in the drawings, or work they excluded hoping you wouldn't notice.

This guide covers what belongs in a complete bid submission, how to compare bids across contractors on an apples-to-apples basis, and the red flags that separate a competitive bid from a liability waiting to happen.

What a Complete Bid Package Includes

Before evaluating the number, verify the submission is complete. A bid missing key documents isn't a bid — it's an opening position for a change order negotiation.

✓

Bid form with lump sum or GMP

Base bid clearly identified, alternates listed separately, unit prices if requested

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Scope clarifications / exclusions list

Written description of what is and isn't included — this document controls scope disputes more than the number itself

✓

Subcontractor list

Which subs are covering each trade package. Unlisted subs are a red flag — they may be TBD, which means the number is not firm

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Schedule / milestone assumptions

What the bid assumes about start date, completion date, and access. Schedule assumptions affect pricing — a bid assuming continuous access may not work for a phased project

✓

RFI list or bid questions

Open questions about drawing conflicts or ambiguous scope. A bidder with a long RFI list reviewed the drawings thoroughly. A bidder with no questions either didn't look, or is pricing assumptions you may not like

✓

Bid bond (if required)

Typically 5–10% of bid amount. Confirms the bidder is bonding-eligible and stands behind their number

How to Compare Bids — Bid Leveling

Bid leveling is the process of adjusting bids to the same scope basis before comparing numbers. You cannot compare a bid that includes all MEP to a bid that excludes plumbing unless you adjust for the difference.

The process:

Step 1: Build a scope matrix

List every major work item (from your drawings and spec) down the left side. List each bidder across the top. For each cell: In / Out / Allowance / TBD. Items marked TBD are scope risk — the number may go up.

Step 2: Identify scope gaps between bidders

Where one bidder shows "In" and another shows "Out," you have a scope gap. Either the low bidder didn't find this scope item, or the high bidder included something that isn't required. Both possibilities are worth investigating before awarding.

Step 3: Normalize to the same basis

Add the cost of excluded items to the low bidder's number. If Bidder A excludes plumbing (estimated at $85K) and Bidder B includes it, Bidder A's adjusted number is their bid + $85K. Compare adjusted numbers, not raw bids.

Step 4: Clarify before awarding

Send each bidder a clarification request listing the specific scope items you need confirmed as included. Get written responses. A scope clarification email before contract is worth more than a contract clause after the fact.

Red Flags in Construction Bids

Red Flag	What It Usually Means
Bid 20%+ below the field	Missing scope or unpriced risk. Before awarding, get itemized pricing for the major CSI divisions to find where the gap is
No exclusions list	The bidder didn't write down what they excluded — meaning everything they didn't price will come back as a change order claim
Subs listed as "TBD"	The GC hasn't priced out those trades. The number is an estimate until subs are locked in
No RFIs submitted	Either the drawings are unusually clean (unlikely) or the bidder didn't review them carefully. Either way, assume scope surprises post-award
Bid based on "drawings only"	The spec book wasn't reviewed. Spec requirements (material standards, testing, submittals) add cost — a "drawings only" bid will miss them
Exclusion of existing conditions	Reasonable for new construction; problematic for TI or renovation work. Clarify what "existing conditions" means and what happens when they differ from the drawings
Unit price list with no quantities	Means the bidder measured nothing — they're planning to bill at unit prices against actual quantities. Your project cost is not fixed

The Pre-Bid Information Gap

Most bid discrepancies trace back to the same root cause: bidders worked from different interpretations of ambiguous drawings. When three contractors read the same set of plans and come up with three different scopes, the problem is usually in the drawings — not the contractors.

The most effective way to reduce bid spread (the range between high and low bids) is to resolve drawing ambiguities before bid day. Send a pre-bid addendum that answers the RFIs, clarifies the scope boundaries, and confirms which spec section governs each disputed item.

Owners who do this consistently see tighter bid spreads, fewer post-award change orders, and faster construction — because everyone starts the project with the same understanding of what was bought.

For GCs reviewing bids from subs:

Tighter bids start with better plan review

SheetIntel analyzes your plan set before bid day — finding scope ambiguities, trade conflicts, and missing specs that drive bid spread. First review is free.

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