The verdict in three sentences
Custom construction software covering site tracking, progress billing and interfacing costs 55,000 to 120,000 € excl. tax, plus 6,000 to 18,000 € per connector (Sage, Cegid, Silae payroll, 2026 e-invoicing). Maintenance runs 800 to 1,700 € a month, for a 14-to-22-week lead time. The real return is financial: 12 hours a week of re-keying removed and a DSO cut by 20 days, which directly lightens working-capital needs.
Cost per integration in 2026
In construction, a tool's value hinges on its connectors: without them, you recreate double entry. Here are the 2026 ranges per flow.
| Integration flow | Role | Indicative cost (one-off) |
|---|---|---|
| Accounting (Sage / Cegid) | entry export, reconciliation | 6,000-14,000 € |
| Payroll (Silae) | site hours → payslips | 7,000-16,000 € |
| 2026 e-invoicing | compliance | 8,000-18,000 € |
| Progress billing | completion, retention | included in build |
| Site tracking | timekeeping, purchases, planning | included in build |
| ERP / CMMS | equipment, maintenance | 10,000-18,000 € |
Each connector has a cost, but each removes a source of double entry and error. 2026 e-invoicing is no longer optional: it's a requirement to build into scope.
Cash-flow ROI
The most tangible gain of integrated construction software is faster progress billing, and therefore faster collection.
| Indicator | Before | After | Effect |
|---|---|---|---|
| Weekly re-keying | 12 h | ~1 h | -11 h/week |
| Progress-billing lead time | 8-10 days | 2-3 days | faster billing |
| DSO (payment delay) | e.g. 75 days | 55 days | -20 days |
| Billing errors | frequent | marginal | fewer disputes |
| Margin visibility per site | monthly | real-time | control |
Cutting DSO by 20 days on significant revenue frees tens of thousands of euros of cash permanently — often more than the cost of the software itself.
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Mini case study
Claire is CFO of a 45-employee construction firm in Paris, with 9 M€ in revenue. DSO was 75 days; the integrated software brings progress-billing issuance to 2-3 days and drops DSO to 55 days. On 9 M€, 20 days of DSO represent about 9,000,000 × 20 / 365 = 493,000 € of cash freed permanently. Add 11 hours a week of re-keying removed (at 35 €/loaded hour, roughly 20,000 € a year). Against a 90,000 € excl. tax build and 1,300 € monthly maintenance, the investment pays back in a few months through the cash effect alone.
FAQ
Is 2026 e-invoicing really mandatory? Yes, the e-invoicing reform applies progressively to companies. Your software must therefore issue and receive invoices in a compliant format: it's a connector to plan into the initial scope.
Can we connect Silae for payroll? Yes. Hours logged on site feed payroll directly, removing re-keying and making payslips more reliable, especially on overtime and allowances.
How long for an integrated construction project? Plan on 14 to 22 weeks depending on the number of connectors. Each integration adds time and cost, hence the value of prioritizing the highest cash-ROI flows.
How does DSO drop by 20 days? By issuing progress billing faster and without error, you invoice earlier and generate fewer blocking disputes. The -20-day figure is a realistic 2026 order of magnitude for a previously manual process.
Should we integrate everything at once? No. A wave-based approach (build + progress billing, then accounting, then payroll, then e-invoicing) spreads the investment and secures each flow before moving on.
Let's scope your project. Tell us your site volume, your current tools (Sage, Cegid, Silae) and your target DSO, and we'll frame a scope with an indicative budget in euros excl. tax. 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.
