Surviving Month-end: Validating a Construction ERP on Real Projects

Month-end is where a construction ERP earns its keep — or quietly falls apart. The individual modules can each look fine, and the month can still be wrong: a cost sitting unapproved, a week of labour stranded on a draft timesheet, a subcontractor certified for work that never hit the job. By the time that surfaces, the profit you reported was borrowed from a future that never arrives.

That's the job the WIP & Month-end Close module does in The ERP Experiment. It's the capstone — it doesn't capture new data, it reconciles everything the other modules captured into a position you can defend.

A WIP schedule, job by job

For every job, the module pulls cost-to-date from job costing, divides it by the current budget to get percentage complete (the cost-to-cost method), and multiplies that by the contract value to get earned revenue — the revenue you've genuinely earned by doing the work.

Then it compares earned revenue to what's actually been billed:

• Over-billing — you've invoiced ahead of the work done. Cash today, a hole tomorrow.
• Under-billing — you've done work you haven't billed. Profit you've earned but not claimed.

Billing on a job here is subcontractor certification from subcontractor billing, with retention still withheld reported alongside. One schedule, every job, the real position.

The close surfaces exceptions — it doesn't bury them

Before you lock anything, the close recomputes the WIP as at the period end and runs the checks that catch a month that only looks finished:

• Undecided costs — actual cost entries still awaiting an approval decision, understating cost.
• Unposted labour — captured hours sitting on draft timesheets that never reached the ledger.
• Unposted cost — certified subcontractor billing that exceeds the cost recorded on the job.
• Retainage anomalies — retention released beyond what was ever withheld.

The first two are blocking — they distort the numbers an executive signs off, so they stop a clean close. The rest are warnings: surfaced, not suppressed.

Locking a period you can defend

Closing freezes the full WIP report as a snapshot against the period, so the figures you signed off are reproducible later — not recomputed from data that has since moved. It also locks the window: costs and labour can't be back-dated into a closed month.

If blocking exceptions remain, you can still close with an explicit override — and that override is written to the period's audit trail with the exception counts. A decision on the record, not an accident.

Reopening, on the record

Sometimes you have to reopen. Construct365 lets you — but never silently. You give a reason, the reopen is logged to an append-only audit trail with who, when and why, and the window unlocks so corrections can post. Re-closing recomputes and re-freezes the snapshot. Every close and reopen stays in the history.

One subscription

WIP & Month-end Close is part of the single ERP Experiment subscription, alongside every other module. Subscribe once and the capstone is unlocked.

👉 Explore the ERP hub, or see how the data it reconciles is captured in job costing, subcontractor billing and labour allocation.