A construction audit checklist is the working list an owner or auditor runs through to confirm that every dollar billed on a project matches the contract terms and the work actually performed. It covers the contract’s audit rights, the documentation to pull, the cost categories where errors and overcharges concentrate, the compliance records that public and federal work requires, and the closeout items that determine whether the final payment gets released. The items below are organized in roughly the order you’d work through them on a real project.
Start With the Audit Rights Clause
Nothing in the checklist matters if the contract doesn’t grant the right to audit. An audit rights clause gives the owner or the owner’s representative access to the contractor’s project-related books, records, and supporting documentation. Without that language, the contractor can refuse to open its files and the owner has no way to compel disclosure.
A workable clause spells out which records are accessible, how much notice the auditor must give, how long after project completion the right survives, and whether the right extends to subcontractor records. On new contracts, push for audit rights that last at least three years past final payment and reach all tiers of subcontractors. The clause should also address who pays for the audit and whether the contractor reimburses audit costs when overcharges exceed a set percentage of the contract value.
Match the Checklist to the Contract Type
How deep the audit runs depends on the contract structure. On a cost-plus (cost-reimbursable) contract, the project is open-book: the owner reimburses actual costs plus a fee, so every invoice, payroll record, and equipment charge is fair game. These audits are exhaustive by nature and account for the bulk of construction audit work.
Lump-sum contracts work differently. The contractor agreed to deliver a defined scope for a fixed price, so the owner generally has less visibility into internal costs. The audit focuses on whether the delivered work matches the contract scope, whether change orders were priced fairly, and whether credits owed to the owner were actually applied. The contractor’s margin on base work isn’t the owner’s concern; markups on changes and the legitimacy of claimed extras are.
Documents to Pull First
Missing paperwork creates delays that benefit no one, so organize the file before anyone starts reviewing invoices. Pull the original prime contract and every signed change order that modified scope or price. Get AIA Document G702 (Application and Certificate for Payment) and the G703 Continuation Sheet, which break the contract sum into a schedule of values showing what’s complete, what’s stored, and what’s been paid to date. Assemble subcontractor agreements and their payment records so each dollar can be traced from the owner’s account through the general contractor to the trade that did the work.
Store records chronologically in project management software or a well-indexed physical system. The goal is a clear line from internal accounting ledgers to the vendor and subcontractor invoices, from each payment to a specific line in the schedule of values, and from each line to the field documentation proving the work was performed.
Labor Costs
Labor is usually the largest single cost category on a construction project, and it’s where billing errors and overcharges appear most often. The checks that matter:
- Confirm hourly wage rates against the rates established in the contract.
- Verify the labor burden percentage applied on top of wages. Burden covers payroll taxes, workers’ compensation, health benefits, retirement contributions, and similar employer costs. A percentage significantly above what actual costs justify becomes profit dressed up as overhead.
- Confirm overtime hours were actually worked, that premium rates match the contract (typically time-and-a-half), and that overtime wasn’t triggered by inefficiency or poor scheduling the owner didn’t authorize.
- Check worker classifications. A laborer billed at a journeyman carpenter rate inflates costs without adding skill. Sometimes it’s intentional, sometimes sloppy recordkeeping; the effect on the owner is the same.
Materials, Equipment, and Subcontractors
Compare material invoices against the quantities actually installed. The classic problem is a contractor ordering in bulk across multiple projects and billing the full quantity to whichever project is being invoiced that month. Watch for purchase orders that don’t match delivery tickets, delivery quantities that exceed what the plans call for, and pricing that ignores negotiated discounts or rebates. Volume discounts a supplier gave the contractor should flow through to the owner on cost-plus work.
For equipment, compare billed rates against published rate guides and the terms in the original agreement. Idle equipment sitting on site while billing continues is a common finding, particularly on delayed projects. Confirm that equipment was actually needed during the periods billed, that rental-versus-purchase economics were considered on long-duration items, and that fuel and maintenance charges are reasonable for the project’s scale.
For subcontractors, trace payments from the general contractor to each subcontractor and confirm that amounts match the subcontract terms with no unauthorized markups layered on. On cost-plus work, the general contractor’s fee on subcontracted work should be clearly separated from the subcontractor’s own charges. Double-dipping, where both the general and the sub mark up the same base cost, is one of the more persistent findings.
General Conditions and Change Order Markups
General conditions cover the contractor’s job-site overhead: temporary offices and trailers, utility hookups, site security, dumpsters, temporary fencing, and site-assigned project management staff. These items usually appear as a separate line in the schedule of values. Verify that general conditions expenses aren’t being billed twice, once through the general conditions line and again inside a subcontractor’s trade costs. Check whether items that should be absorbed as part of the contractor’s fee are being passed through as reimbursable expenses.
Change orders draw heavy scrutiny because they represent work added after the original price was set, often under time pressure and with less competitive discipline. Markups vary by contract. On self-performed work, 10% to 20% for overhead and profit is common; on subcontracted work, the general contractor’s additional markup is often capped at 5% to 10%. The percentages should be in the contract, and the audit confirms the contractor stayed inside them. Also check whether change order work was arguably already within the original scope, a frequent source of disputes where the contractor sees extras and the owner sees base-contract obligations.
Compliance Checks
Prevailing Wage on Public Projects
Federally funded construction projects over $2,000 must pay workers at least the prevailing wage rates set by the Department of Labor under the Davis-Bacon Act.1Office of the Law Revision Counsel. United States Code Title 40 – 3142 Verify that every worker was paid the correct rate for their trade classification, that fringe benefits were paid in cash or contributed to legitimate benefit plans, and that the posted wage scale matched the wage determination in the contract.
The Copeland Act requires contractors and subcontractors on these projects to submit weekly certified payroll statements detailing each employee’s hours, classification, and pay.2Office of the Law Revision Counsel. United States Code Title 40 – 3145 The standard form is the Department of Labor’s WH-347, accompanied by a signed Statement of Compliance certifying the data is accurate and workers received at least the required prevailing wage.3U.S. Department of Labor. Davis-Bacon and Related Acts Weekly Certified Payroll Form Missing or incomplete certified payrolls can hold up final payment and trigger investigations that reach well beyond the audit.
Many state and local public works projects impose their own prevailing wage requirements with different schedules and reporting forms. If the project receives any public funding, confirm which laws apply before starting the audit, because gaps in this documentation are hard to reconstruct after the fact.
Insurance and Lien Waivers
Verify that valid certificates of insurance existed for the prime contractor and every subcontractor throughout construction. Confirm that coverage types and limits matched the contract requirements for general liability, workers’ compensation, and any project-specific policies like builder’s risk or professional liability. Gaps in coverage during active construction create uninsured exposure that may not surface until a claim is filed.
Lien waivers confirm that everyone in the payment chain got paid and gave up their right to file a claim against the property. Four types exist: conditional and unconditional waivers, each for either progress payments or the final payment. Conditional waivers take effect only after payment clears; unconditional waivers take effect on signing regardless of whether the check has been cashed. Confirm that the correct type was collected at each payment milestone and that waivers exist for every tier, from the general contractor through subcontractors and material suppliers. Missing waivers leave the owner exposed to mechanics’ liens filed months after the project wraps.
Permits and Safety Records
Cover building permits and inspection reports from local authorities, confirming the work passed required inspections and met code. Employers with more than 10 employees must maintain OSHA Form 300 logs recording work-related injuries and illnesses.4Occupational Safety and Health Administration. Recordkeeping These logs, along with the annual Form 300A summary, demonstrate that the contractor maintained the safety oversight the law requires.5Occupational Safety and Health Administration. OSHA Forms for Recording Work-Related Injuries and Illnesses Missing safety records can affect the release of final retention payments and signal broader administrative problems.
Indirect Costs and Unallowables on Federal Work
On federal construction contracts and other cost-reimbursable work, indirect cost rates come into play. These are the overhead charges a contractor applies to cover home-office expenses, executive salaries, accounting, and similar costs that can’t be tied to a single project. The Federal Acquisition Regulation requires contractors to certify their proposed indirect cost rates, and a single federal agency establishes the final rates that bind all other agencies.6Acquisition.GOV. Subpart 42.7 – Indirect Cost Rates If a contractor refuses to certify its proposal, the contracting officer can set rates unilaterally at levels low enough to ensure no unallowable costs get reimbursed.
Certain expense categories are flatly unallowable on government contracts no matter how they’re classified: entertainment, alcoholic beverages, charitable donations, country club memberships, lobbying, promotional items, and advertising designed to promote the contractor rather than recruit employees.7Acquisition.GOV. Part 31 – Contract Cost Principles and Procedures Fines, penalties, and costs of defending fraud proceedings are also prohibited from reimbursement. These costs tend to hide inside indirect cost pools, which is where auditors look for them. Submitting unallowable costs in a final indirect cost rate proposal carries statutory penalties on top of the disallowance itself.
These rules apply to federal and cost-reimbursable contracts. On private lump-sum work, indirect cost analysis usually isn’t part of the audit because the owner didn’t agree to reimburse overhead line by line.
Red Flags Auditors Look For
The same problems show up across projects. Knowing what auditors watch for helps both owners and contractors prepare honestly.
- Sales tax billed on exempt projects. Public and institutional projects often carry tax exemptions, but contractors bill sales tax anyway, either by habit or intent.
- Supplier discounts not passed through. A contractor negotiates a volume discount but bills the owner at the pre-discount price and pockets the difference.
- Inflated labor hours or rates. Workers billed at higher trade classifications than the work requires, or hours that don’t match daily field reports.
- Cross-project cost shifting. Materials purchased in bulk get billed entirely to one project when they were used across several.
- Duplicate change orders. The same extra work appears in two separate change orders, sometimes with slightly different descriptions.
- Excessive supervisory staff. More project managers, superintendents, or foremen on site than the work volume justifies.
- Idle equipment charges. Rented equipment sitting unused while billing continues at full daily or weekly rates.
None of these are automatically fraud. Sloppy bookkeeping, miscommunication between field and office staff, and honest accounting errors explain many discrepancies. The pattern matters. A contractor with one missed credit looks careless; a contractor with missed credits, inflated labor, and duplicate change orders looks like something else. The audit sorts out which is which and makes the final number accurate.
Closeout: Retainage Release and Record Retention
Retainage is the percentage of each progress payment the owner withholds until the project is complete, typically 5% to 10% of the contract value. It exists as leverage to ensure the contractor finishes the work and clears punch-list items. Audit findings tie directly into whether retainage gets released.
Before release, the contractor generally must show that all subcontractors and suppliers have been paid (final unconditional lien waivers are the evidence), that required tax obligations have been met, and that all closeout documentation is in order. On public projects, this often includes proof of compliance with unemployment insurance, workers’ compensation, and applicable tax requirements. A step-down clause may reduce the retainage rate after the project crosses a completion milestone, often 50%, but the final portion stays held until all conditions are satisfied. Any questioned costs that survive the contractor’s response reduce the final payment, and unpassed supplier rebates or returned-material credits get captured in the final reconciliation.
Record retention obligations run past closeout. On federal contracts, the Federal Acquisition Regulation requires contractors to keep financial and cost accounting records available for at least three years after final payment, with certain categories requiring four years.8Acquisition.GOV. Subpart 4.7 – Contractor Records Retention Pay administration records like payroll registers must be kept for four years; time cards and petty cash logs, two years. Private contracts don’t have a single federal mandate, but the audit rights clause may set its own retention period. Even without a contractual requirement, keeping core project records for at least six years is prudent given the statute of limitations on breach-of-contract claims in most jurisdictions. Store them in a format that stays accessible, because a flooded warehouse or a decommissioned server can turn a defensible position into an indefensible one.