The verdict in three sentences
A main contractor with 180 staff running 45 projects a year too often discovers margin drift at final account, when nothing can be fixed. Off-the-shelf construction ERP at GBP 130-300 per user per month handles accounting and payroll, but poorly connects mobile site timesheets, purchasing and monthly progress valuations. A custom module at GBP 43,000 to 82,000, delivered in 5 to 7 months, detects margin drift 2 months earlier, which is often enough to save 1 to 2 points on a project.
Where a project's margin leaks
In a London structural contractor, margin depends on three poorly connected flows: operatives' hours, written on paper and re-keyed on Monday, purchases of concrete, rebar and plant hire, coded to the project two to four weeks late, and monthly valuations, prepared by the project manager in Excel. The finance director only gets a reliable margin at practical completion. On a GBP 1 million project, a 3-point drift is GBP 30,000 lost.
| Metric (180 staff, 45 projects/yr) | No connected tool | With connected project module |
|---|---|---|
| Annual revenue | GBP 27,500,000 | GBP 27,500,000 |
| Time to know real margin | 2 to 3 months after the fact | weekly |
| Timesheet hours re-keyed per week | 12 to 15 h | under 2 h |
| Time to issue applications for payment | day 8 to 12 | day 2 |
| Average gap planned vs final margin | 2.5 to 4 points | 1 to 1.5 points |
| Uncoded purchases at month-end | 8 to 12% | under 2% |
| Retention tracked | spreadsheet | automatic schedule at 5% |
These figures are a 2026 order of magnitude for a London-area building SME. Issuing applications 6 days earlier also helps cash flow: on GBP 2.3 million invoiced per month, it releases several hundred thousand pounds of working capital.
Construction ERP or custom module: the 2026 comparison
UK construction ERPs are complete on accounting, CIS deductions, payroll and commercial management. They are less flexible on site timesheets, mobile ergonomics for foremen and each contractor's own logic for allocating costs.
| Criterion | Off-the-shelf construction ERP | Custom module connected to the ERP |
|---|---|---|
| Upfront cost | GBP 13,000 to 34,000 deployment | GBP 43,000 to 82,000 |
| Recurring cost (25 users) | GBP 130 to 300/user/month, i.e. GBP 39,000 to 90,000/yr | GBP 7,000 to 13,000/yr maintenance |
| Mobile site timesheets | optional module, weak offline | offline app, 180 operatives |
| Progress valuations | standard template | progress per package, JCT valuations, retention |
| Project margin | at accounting close | weekly, per package and cost line |
| Time to go live | 6 to 12 months | 5 to 7 months |
| Roadmap | vendor's priorities | your priorities |
The most common setup keeps the ERP for accounting and payroll and adds a project module feeding it by API or export: budgets, timesheets, purchases, valuations and margin dashboard.
Scope of the project module
An effective project module includes: the initial budget per package and cost line (labour, materials, subcontract, plant), mobile timesheets with geolocated site check-in and offline mode, coding of purchase orders and supplier invoices, monthly applications for payment with progress per package and JCT payment notice deadlines, retention and bond tracking, and a margin dashboard comparing budget, committed and actual. Export to the accounting ERP and payroll removes all re-keying.
Mini case study
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Rachel, finance director of a 180-person structural contractor in London, turns over GBP 27.5 million across 45 projects. She invests GBP 67,000 in a project module connected to her ERP, plus GBP 10,000 a year in maintenance. The module cuts the average margin gap from 3 to 1.5 points on the third of projects where drift is recoverable, i.e. 1.5% x GBP 9,200,000 = GBP 138,000 a year. The 13 weekly hours of re-keying drop to 2, i.e. 11 h x 46 weeks x GBP 35 = GBP 17,710. Total gain: GBP 155,710, minus GBP 10,000 maintenance, i.e. GBP 145,710 net. Payback in under 6 months.
FAQ
How much does construction project software cost in 2026?
A construction ERP costs GBP 130 to 300 per user per month, plus GBP 13,000 to 34,000 to deploy. A custom project module runs GBP 43,000 to 82,000.
Do mobile timesheets work without signal on site?
Yes, the app stores entries offline and syncs when signal returns. A foreman can clock in 8 operatives in under 2 minutes.
Do valuations handle retention and payment notices?
Yes, 5% retention and JCT payment and pay-less notice deadlines are calculated automatically. The application is ready on day 2 instead of day 8.
Do we need to change our accounting ERP?
No, the module connects to your existing ERP by API or file export. Accounting, CIS and payroll stay in your current tool.
How long until a first pilot project?
A 3-project pilot starts after 3 months. Full rollout to 45 projects takes 5 to 7 months in total.
Let's scope your project. Send us your project count, current ERP and a sample valuation: we will price the project module with an indicative budget and rollout plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33. Request a free quote
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
