A construction ERP is an ERP organised around the job or project rather than the product. It must track each job's budget against committed and actual cost, bill clients by progress or valuation, hold and release retentions, pay subcontractors correctly, and cost plant and equipment to the jobs that use them. General ERPs often handle these awkwardly.
Contractors usually feel the gap when the accounting package shows a profitable month while site managers know two jobs are overrunning. The problem is timing: cost is committed through orders and subcontracts long before invoices arrive, and revenue depends on valuations, variations and retentions. This guide is for contractors and specialist subcontractors in the US, UK and UAE. If your jobs, contracts or payment terms do not fit a standard package, our custom ERP software page explains how we build job-centred systems around your contracts.
Why do construction companies need a different kind of ERP?
Because profit is earned job by job over months, and most of the cost is known before it is invoiced. A construction ERP has to answer "what will this job cost to complete?" at any point, not just "what have we spent?".
| General ERP assumption | Construction reality |
|---|---|
| Revenue is invoiced when goods ship | Revenue is applied for by valuation or progress, then certified |
| Cost arrives with the supplier invoice | Cost is committed by purchase orders and subcontracts weeks earlier |
| Customer pays the full invoice | Retentions are held back and released at completion and after a defects period |
| Products have fixed prices | Variations change the contract value during the job |
| Assets sit in one place | Plant moves between sites and is costed per day or hour |
What should construction job costing include?
Job costing should show, for every job and cost code, the budget, committed cost, actual cost, forecast cost to complete and forecast margin. Check these points in every demonstration:
- Cost codes or a cost breakdown structure that matches how your estimators price work (for example by trade, stage or element), so estimates flow into budgets without rekeying.
- Commitments. Purchase orders and subcontract orders should show against the job as committed cost the moment they are approved.
- Labour costing from timesheets or site apps, with rates that include on-costs where you use them.
- Forecast to complete that a commercial manager can update per cost code, with history of previous forecasts.
- Variations tracked from instruction to pricing to approval, adjusting both contract value and budget.
Cost and revenue figures should reconcile to the general ledger. If the job report and the accounts disagree, finance will stop trusting the job report.
How should progress billing and retentions work?
Billing should be generated from the contract: schedule of values or bill of quantities, percentage or quantity complete per line, approved variations, less previous applications and retention. Applications, certified amounts and invoices are not always the same number, so the system should store all three.
Retentions need their own ledger. The ERP should:
- Calculate retention per application at the contract rate
- Track retention receivable from clients and retention payable to subcontractors separately
- Record release dates (practical completion, end of defects period) and alert before they fall due
- Show retention balances by job, client and subcontractor
Retention terms are set by your contracts; in the US the same idea is usually called retainage. Model the terms you actually sign rather than a generic rule.
What does subcontractor management need?
Subcontract orders, valuations of subcontractor applications, deductions (retention, discounts, contra charges), compliance documents such as insurance certificates with expiry dates, and payment runs. The system should stop payment when required documents have expired, and should show what is owed to each subcontractor by job.
In the UK: Construction Industry Scheme (CIS)
UK contractors also have HMRC obligations under the Construction Industry Scheme. Checked on gov.uk in October 2026, HMRC's guidance for contractors says:
- Contractors must verify subcontractors with HMRC, which tells them the deduction rate to apply.
- The deduction rates are 20% for registered subcontractors, 30% for unregistered subcontractors and 0% for subcontractors with gross payment status.
- The deduction is calculated after taking away amounts the subcontractor paid for VAT, materials and certain other costs listed by HMRC.
- Monthly returns must reach HMRC by the 19th following the end of the tax month (tax months run from the 6th to the 5th), and a payment and deduction statement must be given to the subcontractor within 14 days of the end of the tax month.
- CIS records must be kept for at least 3 years after the end of the tax year they relate to.
HMRC's guidance on the VAT domestic reverse charge for building and construction services also applies to most supplies reported within CIS between VAT-registered businesses. A UK construction ERP should hold verification results per subcontractor, calculate deductions on the right base, produce payment and deduction statements and the monthly return data, and handle reverse charge invoices. Confirm the details with your accountant and the current gov.uk guidance; we design systems to support these obligations, and responsibility for filing stays with the contractor.
For US and UAE contractors, payment, retention and tax treatment is set by contracts and local rules; capture your requirements with your accountant rather than assuming a UK-style scheme.
How should equipment and plant be handled?
Owned and hired plant should be costed to jobs by day, hour or usage, with maintenance history, inspection dates and location. Hired plant needs off-hire tracking, because forgotten hires are a common, avoidable cost. If plant is a large part of your business, test the package's equipment module specifically; it is often thinner than its finance features.
What should site teams record in the system?
Site teams should record the facts that drive cost and claims, on a phone or tablet, the same day. Most construction data problems start because the site keeps its own records in notebooks and spreadsheets that reach the office late.
- Timesheets by job and cost code, approved by the site manager.
- Deliveries received against purchase orders, with photos of delivery notes and any shortages.
- Daily diaries: weather, labour on site, delays, instructions received and visitors.
- Photos and progress tagged to areas or schedule lines, supporting valuations.
- Plant on and off hire, so hire stops when the machine leaves site.
- Snags and defects with locations and photos, feeding the retention release process.
A site app only works if it is quick and works with a weak signal. Our employee field apps page covers offline-capable apps connected to an ERP.
How should you score construction ERP options?
Score each option after a scripted demonstration on one of your real jobs. Agree the weights first.
| Criterion | Suggested weight | What a 5 out of 5 looks like |
|---|---|---|
| Job costing and forecasting | 25 | Budget, committed, actual and forecast by cost code, matching the ledger |
| Applications, variations and retentions | 20 | Your last two applications reproduced, retention balances correct |
| Subcontractor management | 15 | Valuation, deductions, document checks and payment in one flow |
| Site data capture | 15 | A site manager records a diary and timesheet in minutes, offline |
| Plant and equipment | 10 | Hire tracking and job charging without spreadsheets |
| Local compliance (for example UK CIS) | 10 | Verification, deductions and statements handled in the system |
| Total cost and support | 5 | Written costs for licences or build, implementation and support |
Construction ERP requirements checklist
- Estimating output imports into job budgets by cost code
- Committed, actual and forecast cost per job and cost code
- Variations with status, value and approval trail
- Applications, certifications and invoices stored separately
- Retention receivable and payable with release dates and alerts
- Subcontract orders, valuations, deductions and document expiry
- UK only: CIS verification, deductions, statements, monthly return data and reverse charge VAT
- Plant costing, hire tracking and inspection dates
- Site apps for timesheets, deliveries, diaries and photos
- Job reports reconciling to the general ledger
- Approval rules for orders and subcontracts (see our approval workflow design guide)
Package or custom ERP for construction?
Several packaged products are built specifically for construction and handle job costing, retentions and subcontractors as standard; general ERPs can be extended to do the same. For a contractor whose contracts and processes are typical for its market, a construction-specific package is often the sensible first look.
| Your situation | Usually better fit |
|---|---|
| Typical contracts, one company, standard reporting | Construction-specific package |
| General ERP already in place for other businesses in the group | Extend it with job costing, or integrate a construction module |
| Unusual contract forms, design and build with heavy variation flow | Test packages hard; custom job and commercial module if they fail |
| Field operations are the bottleneck (diaries, timesheets, deliveries) | Custom site app integrated with your current system |
| Several companies, joint ventures or project companies | Custom or larger suite; see multi-entity ERP governance |
For accounting-level job costing, our guide to ERP project accounting covers work-in-progress and revenue recognition in more depth.
When this is not the right approach
If you run a small number of jobs a year and your accountant already produces reliable job reports, a full ERP may be more system than you need; a job costing tool on top of your accounts can be enough. If your real pain is site reporting, start with a site app. And if estimating and contracts are inconsistent from job to job, standardise them before you automate them.
How to start
Prepare a sample job: the estimate, the contract terms (payment, retention, variations), two recent applications, the subcontract list and the monthly job report you wish you had. List the reports your commercial team and directors read, and the systems you use for estimating, payroll and accounts. Our ERP RFP template helps structure it.
Then discuss the project with us. Timeline Digital builds 2 to 3 key modules as a free pilot before the full project starts; for contractors that is often job costing with commitments, subcontractor valuations, or a site app, tested on a live job.