Construction bookkeeping: the document checklist

Two things make construction books different. First, everything is coded to a job, so a receipt without a job reference is nearly useless and has to go back to the client. Second, a chunk of the paperwork is compliance rather than accounting — W-9s, certificates of insurance, lien waivers — and it is your problem in practice even when it is not strictly bookkeeping.

The workflow reality that catches remote bookkeepers: field staff hand paper receipts to someone in an office who tags them with a job and cost code before they reach you. If you are remote, that tagging step has to be rebuilt, and it is the part that breaks.

Request every month

Job-level documents should arrive continuously; the rest can be monthly.

• Bank and credit card statements for all accounts
• Receipts and material invoices tagged with job and cost code
• Supplier and vendor invoices, with delivery tickets where relevant
• Subcontractor invoices, with job reference
• Progress billings and AIA applications for payment issued to customers
• Customer payments received, including any retainage withheld
• Change orders — signed, with amounts
• Equipment rental invoices by job
• Payroll reports including any certified payroll and per-job labour hours
• Fuel and vehicle expenses, allocated by unit or job where possible
• Loan and equipment finance statements

Request quarterly or annually

• Per subcontractor, before first payment: W-9 and current certificate of insurance. Chase these before the work starts, not in January.
• Per job, at milestones: lien waivers exchanged with subs and suppliers.
• Quarterly: WIP schedule inputs — contract value, costs to date, estimated cost to complete, billings to date.
• Quarterly: payroll tax filings and any certified payroll reports.
• Annually: insurance and bonding renewals, workers' comp audit paperwork.
• Annually: 1099 detail for every subcontractor.

Ask before you onboard

These are the questions that decide whether you have priced the engagement correctly. Ask them on the first call, not in month three.

• Do you job cost, and are cost codes already set up?
• Fixed-price, time and materials, or cost-plus — and does it vary by job?
• Do you bill progressively, and is retainage withheld?
• How many subcontractors do you use, and do you already collect W-9s and COIs?
• Is anyone producing a WIP schedule, and does your CPA expect one?
• Who approves invoices before they reach me, and how?
• How do field receipts get from the site to the office today?
• Any certified payroll or prevailing wage jobs?

Traps that catch bookkeepers new to construction

Retainage booked as bad debt. Retainage withheld on a progress billing is still receivable — it just is not due yet. It belongs in a separate retainage receivable account, not written off or ignored because it never arrived.

No job on the transaction. Once a month closes with untagged costs, job profitability is permanently wrong for that period. Push back on untagged receipts in the week, not at month end.

Missing subcontractor W-9s. The cost of chasing a W-9 in January from a sub who finished in March and has since moved is enormous. Make it a condition of the first payment, and collect the certificate of insurance at the same time.

Change orders that never reach the books. Verbal change orders are normal on site and invisible in the ledger. If contract value in the books does not match what was actually agreed, the WIP schedule is wrong and so is every margin figure.

Owner's personal vehicle and tools. Trades clients mix personal and business constantly — a truck, a garage full of tools, a phone plan bundled with the family. Establish the split and the documentation up front rather than guessing each month.