The verdict in three sentences
For a general contractor delivering 15 to 40 projects a year, margin is lost on site: unpriced extra works, lingering snags, valuations sent late. A custom build at €35,000 to €90,000 with a mobile field app, delivered in 4 to 6 months, typically protects 1 to 3 margin points per project. Off-the-shelf tools at €50 to €150 per user per month are enough as long as your processes are standard and your teams small.
The hidden cost of tracking by email
On a €1.5 million project, net margin sits around 4 to 7%. Losing 2 points means losing €30,000. The causes are always the same, and they are measurable.
| Loss source | Observed frequency | 2026 impact (€25M revenue) |
|---|---|---|
| Extra works not signed off as variations | 3 to 6 per project | €150,000 to €400,000 per year |
| Snags not cleared before retention release | 10 to 20% of snags | 5% retention held 6 to 12 months |
| Late interim valuations | 7 to 15 days late | Working capital up €300,000 to €600,000 |
| Delay penalties | 1 project in 5 | €20,000 to €80,000 per year |
| Loose subcontractor tracking | 2 to 4% variance | €60,000 to €150,000 per year |
| Site managers' admin time | 8 to 12 h per week | One full-time role lost |
Custom or market software: 2026 comparison
| Criterion | Off-the-shelf construction tool | Custom |
|---|---|---|
| Initial cost | €1,000 to €5,000 | €35,000 to €90,000 |
| Annual cost (30 users) | €18,000 to €54,000 | €6,000 to €12,000 |
| 5-year cumulative cost | €91,000 to €275,000 | €65,000 to €150,000 |
| Offline field app | Depends on vendor | Yes, photos, drawings, geotagged snags |
| Interim valuations | Standard templates | Matched to your public and private contracts, price adjustment |
| Accounting and payroll integration | Generic connectors | On your own tools |
| Subcontractor and client portal | Rare | Document upload, sign-off of handover certificates |
Custom wins beyond 20 users or when the company does a lot of public work, with specific valuation and price adjustment formats.
The scope that protects margin
| Module | Indicative budget | Expected gain |
|---|---|---|
| Field app (diary, photos, snags) | €12,000 to €25,000 | Snags cleared twice as fast |
| Variations and extra works | €6,000 to €15,000 | 80% of extras approved before execution |
| Interim valuations and price adjustment | €8,000 to €20,000 | Sent on day one of the month |
| Subcontractor and labour tracking | €5,000 to €15,000 | Variance below 1% |
| Handover certificates and snag clearing | €4,000 to €10,000 | Retention released earlier |
| Margin dashboard per project | €3,000 to €8,000 | Alert at 1 point of drift |
The app must work offline in basements or dead zones, then sync. This is the criterion that makes site managers adopt, or reject, the tool.
Mini case study
Tom, operations director of an 80-person general contractor in Manchester, turns over €25 million across 30 projects a year. He invests €68,000 in a field app, the variations module and valuations. By protecting 1.5 margin points, he recovers €375,000 a year. Even with a real gain half as large, the project pays back in under 5 months, including €9,000 a year of maintenance.
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FAQ
Will site managers really use it?
Yes if the app takes under 5 minutes a day: photo, voice snag, signature on tablet. We co-design with 2 or 3 site managers during the first 3 weeks.
Does it work without signal?
Yes. Data stays on the phone and syncs when the network returns, including PDF drawings of several hundred MB.
Can we reuse our Excel valuation templates?
Yes, they form the basis of the module. Migrating and configuring formats costs €2,000 to €5,000.
How soon are we operational?
A first phase (field app and snags) is usable in 8 to 10 weeks. The full project takes 4 to 6 months.
Who owns the software?
You do. Source code and data are handed over, avoiding vendor lock-in and imposed price increases.
Let's scope your project. Send us your project volume, site headcount and current tools, and we will price a phased scope with indicative budget and timeline. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
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.
