Where Construction Budgets Leak: 10 Line Items Nobody Checks
A general contractor's bid comes in at $31.2M. Internal review takes four days — the estimating team is two people carrying three other projects. They check the large divisions, reconcile the totals, ask a few questions, get answers, sign off.
Eleven months later the project lands at $36.1M.
There was no fraud. There was roughly 4% of overstated quantities, two rates applied to the wrong assemblies, and four design packages that didn't exist when the bid was priced. Every one of those was visible in the documents on day one. Nobody had the hours to look.
Here's where it accumulates.
1. Quantity takeoffs nobody independently verified
The largest and least interesting category of loss. Quantities get carried over from the contractor's previous project, taken from a superseded drawing revision, or derived from area-based rules of thumb rather than measured.
Verifying them means reconciling every line against the drawings and specifications — dozens of hours of unglamorous work. So it gets sampled: the big divisions get checked, the rest doesn't. But the leak isn't concentrated in the big divisions. It's spread evenly across hundreds of small lines, none of which individually justifies the effort.
2. Scope counted twice
Composite and assembly rates already include preparation, minor handling, and incidental operations. Those same operations then appear again as separate line items.
Catching it requires reading the inclusion list behind every rate applied. The contractor's estimator knows those inclusions cold — it's daily work for them. For you it's an occasional exercise against a deadline.
3. The right price for the wrong assembly
The rate exists, the description matches at a glance, and it describes different conditions: a different material, a different working height, a different installation method. The spread between adjacent assemblies is routinely 20–40%.
Related: pricing built on a superseded cost database or the wrong index period. The arithmetic reconciles, the backup looks legitimate, the number is wrong.
4. Escalation clauses with no ceiling
In a volatile materials market some escalation provision is reasonable. Uncapped escalation is not — it's an open-ended claim on your contingency.
A defensible clause has three things: a cap, a named published index, and a documentation requirement. Missing any one of them, the provision transfers all market risk to you while leaving the contractor's margin intact.
5. Vendor quotes without competitive backup
Items outside the standard cost database get priced from supplier quotations. The quotations are either absent, or three quotes arrive where two come from related entities, or they cover different quantities and delivery terms and therefore aren't comparable at all.
The check isn't "is backup attached." It's "does the backup support the number."
6. Incomplete design at tender
Contractors price what exists. Packages that are unissued, incomplete, or internally inconsistent aren't in the bid — which is precisely why the bid looks competitive.
That scope returns later as change orders, priced without competitive pressure: the contractor is mobilized, the schedule is committed, and there is no alternative bidder. Change order pricing bears no relationship to tender pricing.
This is catchable exactly once — during a completeness review of the design documents before contract execution.
7. Interdisciplinary clashes
Electrical loads that don't match mechanical equipment schedules. Plumbing routed through structure that isn't shown on the architectural drawings. Levels that disagree between structural and architectural sets.
Every clash is a stoppage, a rework, and a change order. They're normally discovered during installation — the single most expensive moment in the lifecycle of a drawing error. Cross-discipline reconciliation is a distinct exercise that almost nobody runs internally, because it requires every discipline in the room at once.
8. Pay applications that don't reconcile
At execution stage the same logic applies, but the money moves faster.
A front-loaded schedule of values on the G703 puts your cash ahead of the work. Percent-complete claims exceed installed quantities. Stored materials are billed without adequate documentation or insurance. Retainage is released early. Lien waivers don't match the payees actually on site.
Your field team cannot physically measure everything. Reconciling a G702/G703 against the schedule of values, prior applications, and the as-built record is desk work — done against documents, not on the deck.
9. Equipment, commissioning, and startup
Equipment carried in both the contractor's price and a separate owner-supplied procurement package. Commissioning priced inside the installation line and again as a standalone division. Or startup and training omitted entirely, surfacing weeks before handover when the schedule has no slack left to negotiate.
10. Contract terms
The most expensive category, because it governs everything for the life of the project.
Allowances that function as blank cheques. Contingency the contractor controls rather than the owner. Liquidated damages that aren't symmetrical with the risk you carry. Notice provisions so short that legitimate claims survive and yours expire. Weak warranty language. Vague procedures for pricing and approving variations.
The estimate describes money today. The contract describes who pays for everything that goes wrong later.
Why internal review doesn't catch this
Not a competence problem. A process design problem.
Time asymmetry. The contractor spent three weeks assembling the bid. You have four days, because the tender calendar is fixed.
Expertise asymmetry. A complete review needs a quantity surveyor, a structural engineer, discipline engineers for each MEP package, and a construction lawyer — simultaneously. Internally those people either don't convene, or they convene on projects an order of magnitude larger.
Sampling. Big lines get checked. The leak lives in the small ones, and in aggregate it's larger.
Incentive. Once the contractor is selected and the board date is set, the project quietly acquires an interest in the bid clearing review.
The arithmetic
A 3% discrepancy on a $30M project is $900,000. At 5% it's $1.5M. These aren't allegations of bad faith — that's the normal accumulated error in an unverified estimate produced under commercial pressure.
Against those figures, the cost of systematic document review is not a line worth optimizing.
What MEXUM does
Upload estimates, drawing sets, specifications, contracts, change orders, and pay applications. Fourteen specialist modules review the documents in parallel — quantities, unit rates, price substantiation, design completeness, cross-discipline conflicts, code compliance, and contract risk. You receive a written report identifying specific line items, the basis for each finding, and the quantified exposure, within 24 hours.
We operate in 40+ countries and work to IRC, IBC, EN Eurocodes, and local building standards, so portfolios spanning multiple jurisdictions are reviewed against the code that actually applies.
Reviews start at $100. Enterprise plans are available for continuous review across a portfolio.
Start with the one estimate currently sitting in your approval queue. The report will tell you what signing it would have cost.