What internal controls should a construction company have over accounts payable?

Key takeaways

• Segregation of duties between AP clerks, approvers, and payment signers prevents unauthorized transactions and fraud.
• Three-way matching of purchase orders, invoices, and receipts ensures payments are legitimate and accurate before they're processed.
• Automated approval workflows route invoices through appropriate review levels based on amount, account, or project.
• Vergo brings card spend, employee reimbursements, and AP invoices into one coding model with inference-based coding and optional approval routing by GL account, amount, or project.
• Complete audit trails and lien waiver documentation protect against legal exposure and support compliance with IRS Accountable Plan rules.
• Integration with accounting and ERP systems ensures work-in-progress and job cost reporting remain accurate and current.

Why construction companies need rigorous AP controls

Construction companies face unique accounting risks that make internal controls over accounts payable essential. Auditors examine AP processes closely, looking for transparent approval workflows, complete documentation, and consistent policy enforcement. Without these controls, firms risk tax reclassification of reimbursements as taxable income, vendor fraud, lien exposure from missing waiver documentation, and audit findings that can delay progress payments or disrupt cash flow. The combination of high transaction volumes, field-based purchasing, subcontractor relationships, and job costing requirements means that weak AP controls create both compliance and operational problems. Construction-specific regulations like lien waiver requirements and IRS Accountable Plan rules add further scrutiny to how invoices and reimbursements are documented and paid.

Segregation of duties in the AP process

The first line of defense against fraud and error is ensuring that no single person controls the entire payment cycle. One employee should enter invoices, a different person should approve them, and a third should execute payments. This separation prevents an individual from creating a fraudulent vendor, approving a false invoice, and issuing payment without oversight. In construction environments where field teams initiate purchases and office staff process payments, natural separation often exists, but it must be formalized and enforced. The control works only when the organization maintains clear role definitions and prevents employees from acting outside their assigned functions. Documentation of who performed each step creates an audit trail that both deters misconduct and enables investigation if discrepancies arise.

Three-way matching and invoice verification

Before any payment is made, construction companies should verify that three documents align: the purchase order that authorized the purchase, the invoice from the vendor, and the receiving document or proof of delivery. This three-way match confirms that the company ordered the goods or services, received what was ordered, and is being billed the correct amount. Discrepancies between these documents signal potential problems—duplicate invoicing, quantity errors, pricing mistakes, or even fraudulent billing. In construction, where materials deliveries occur across multiple job sites and services span weeks or months, matching becomes more complex but also more important. The control prevents paying for materials never delivered, services never performed, or amounts never agreed upon. Companies that skip this verification often discover the errors only during job cost reviews or audits, when correction is difficult and costly.

A practical example: preventing duplicate payments on a commercial project

A general contractor working on a mixed-use development receives an invoice from a concrete supplier for $47,000. The AP clerk enters the invoice and routes it for approval. The project manager compares it against the purchase order issued three weeks earlier and the delivery tickets signed by the site superintendent. She notices that the invoice total matches the PO, but two of the six delivery tickets were already billed on a previous invoice that was paid last month. The three-way matching process catches the duplication before payment goes out. The project manager contacts the supplier, who acknowledges the billing error and issues a corrected invoice for $31,000 covering only the four unbilled deliveries. Without the matching control, the company would have overpaid by $16,000 and spent weeks trying to recover the funds or apply a credit to future orders.

Approval workflows and spending authority

Every construction company should define who can approve payments and under what circumstances. Approval authority typically varies by transaction amount, GL account category, and project. Small material purchases might require only a project manager's sign-off, while subcontractor invoices over a certain threshold need both PM and controller approval. Equipment rentals charged to overhead accounts might follow a different path than job-specific costs. Vergo's optional approval workflows fit how construction companies already control spend, routing by GL account, by amount, or by project, while policy flags catch what breaks a rule without requiring manual intervention. The workflow must be documented, communicated, and enforced consistently. Automated routing ensures invoices reach the right approvers based on these criteria without manual sorting or email chains. When approval steps are optional, the system should flag transactions that break policy rules—unusual vendors, over-budget amounts, missing documentation—so reviewers focus attention where risk is highest. Clear approval workflows also establish accountability, making it obvious who authorized each payment if questions arise later.

Audit trails and lien waiver documentation

Construction companies must maintain complete records of every AP transaction, including who entered it, who approved it, when it was paid, and what supporting documents were attached. This audit trail serves multiple purposes: it satisfies external auditors, supports job costing accuracy, enables dispute resolution with vendors, and provides evidence of compliance with lien waiver requirements. Many states require general contractors to obtain conditional and unconditional lien waivers from subcontractors and suppliers before and after payment. Missing waivers expose the property owner and general contractor to mechanics' liens even after payment was made. Internal controls should prevent payment until the appropriate waiver is received and filed. Linking waiver collection to the AP workflow ensures compliance happens automatically rather than relying on manual tracking that's easy to overlook during busy periods.

How Vergo handles this

Vergo supports the internal controls construction companies need over accounts payable by bringing card spend, employee reimbursements, and AP invoices into one coding model. Transactions are ready to code the moment they happen, with no waiting for clearing, and Vergo proposes the coding by inference from your accounting structure and history—including GL account, project, and cost code—with no rule library to build or keyword lists to maintain. Every coding shows why it was chosen, so a reviewer confirms in seconds instead of re-coding by hand. Approval workflows are optional and fit how you already control spend: route by GL account, by amount, or by project, or skip approval flows entirely and let policy flags catch only what breaks a rule. Employees handle everything by text message, with no app to download or portal login, and Vergo chases missing receipts itself. Once transactions clear, they sync into your accounting or ERP software. Connecting your existing cards involves no card applications, no re-issuing, and no banking change.

Related questions

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