The verdict in three sentences
A custom construction site management system costs EUR 45,000 to 100,000 in 2026 and ships in 5 to 8 months, versus EUR 40 to 120 per user per month for an off-the-shelf construction SaaS. The real payoff isn't data entry: it's per-site margin tracking, which surfaces 8 to 15 % of unbilled slippage on variations and purchases. Without an offline-capable field mobile app, none of that data flows back, so it is the first selection criterion.
What construction software costs in 2026
A London SME has two routes: a vertical SaaS (fast, but rigid on progress billing and margins) or custom software (aligned with your processes, but with upfront investment). Order of magnitude for 2026:
| Item | Standard construction SaaS | Custom build |
|---|---|---|
| Setup / initial dev | EUR 2,000 - 8,000 | EUR 45,000 - 100,000 |
| Monthly cost | EUR 40 - 120/user/mo | Hosting EUR 80 - 250/mo |
| Time to go live | 2 - 6 weeks | 5 - 8 months |
| Offline field app | Variable, often limited | Included, tailored |
| Per-site margin tracking | Basic | Fine, per lot and variation |
| Annual maintenance | Included in subscription | 10 - 15 % of build/yr |
For a team of 8 site managers, a SaaS at EUR 70/user/mo runs to EUR 6,720/yr, roughly EUR 34,000 over 5 years. Custom becomes worthwhile when your business rules (progress statements, retention, subcontracting) don't fit the standard boxes.
The modules that make the difference
Useful site software links the quote to final invoicing without re-keying. Modules to price and their typical impact:
| Module | What it delivers | Estimated 2026 gain |
|---|---|---|
| Quotes and price library | Fast, consistent pricing | +20 % quotes issued |
| Multi-site planning | Load/resource view | -15 % idle time |
| Mobile site tracking | Clock-in, photos, progress | Real-time data |
| Progress billing | Bill by completion | -30 % billing delay |
| Purchase and margin tracking | Real margin per site | +8 to 15 % margin recovered |
| Retention tracking | Automatic follow-up | No missed collections |
Offline mode is not a luxury: in a basement or peri-urban site, mobile signal drops. A lost entry means an unbilled variation.
Mini case study
Mark runs a structural works SME in London: 8 site managers, 42 sites/yr, EUR 7.4M turnover. Before the tool, margins were computed at the end of each site in Excel, three weeks late. An audit revealed 11 % average unbilled slippage on variations and purchases, about EUR 240,000/yr in lost margin. He invests EUR 68,000 in custom software (delivered in 6 months) plus EUR 9,500/yr maintenance. Recovering even half the slippage (EUR 120,000/yr), payback lands in under 9 months.
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FAQ
SaaS or custom for a construction SME?
Below 5 site managers with standard processes, a SaaS at EUR 40-120/user/mo often suffices. Beyond that, or if your progress statements and margins are specific, custom (EUR 45,000-100,000) pays off quickly.
Is offline mode really essential?
Yes. On site, connectivity is unreliable. A field app that syncs clock-ins, photos and progress once the network returns prevents data loss and secures variation billing.
How long to deploy?
Allow 5 to 8 months for a full custom build, with a usable first version (quotes + tracking) by month 3. A SaaS starts in 2 to 6 weeks but without deep customization.
What annual maintenance budget?
Maintenance of 10 to 15 % of dev cost, roughly EUR 6,500 to 15,000/yr for a EUR 65,000-100,000 project. It covers fixes, regulatory updates and support.
Will it integrate with my accounting?
Yes, a bridge to your accounting software (export of statements, invoices, purchases) is standard. Budget EUR 5,000 to 12,000 depending on the automation level.
Let's scope your project. Tell us your site volume, field headcount and billing rules, and we'll define scope, an indicative budget and a realistic 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.
