The verdict in three sentences
On a construction site, the hidden cost is not the drawing: it is the wrong version of the drawing circulating by email. A collaborative construction extranet centralizes drawings, progress claims and subcontractor documents with versioning and per-site access control — a 2026 budget of 35,000 to 80,000 EUR excl. VAT over 14 to 20 weeks. The return shows up as avoided rework: 15 to 20% fewer disputes and delays on the affected work packages.
Cost per functional package in 2026
A construction extranet is delivered in packages. You can open drawing management from week 8 and add electronic signature later.
| Functional package | Scope | 2026 cost (EUR excl. VAT) | Timeline |
|---|---|---|---|
| Core + per-site access | Roles, subcontractor invites, EU hosting | 9,000 – 16,000 | 3 – 4 wks |
| Drawing versioning | Drawing vault, distribution, revisions, alerts | 8,000 – 15,000 | 3 – 5 wks |
| Progress claims | Progress, approval, history | 6,000 – 13,000 | 3 – 4 wks |
| Subcontractor documents | Compliance certificates, checks | 5,000 – 11,000 | 2 – 3 wks |
| Electronic signature | Contracts, minutes, amendments | 4,000 – 9,000 | 2 – 3 wks |
| Site reporting | Dashboards, export | 3,000 – 8,000 | 2 – 3 wks |
The total reaches 35,000 to 72,000 EUR excl. VAT, consistent with the range. Drawing versioning is the most critical package: it eliminates rework caused by outdated revisions.
Custom extranet or construction SaaS platform?
Specialized SaaS platforms exist (e.g. Kroqi, Finalcad). They deploy fast but charge per user and impose their workflows.
| Criterion | Custom extranet | Construction SaaS |
|---|---|---|
| Upfront cost | 35,000 – 80,000 EUR | 0 – 8,000 EUR |
| Recurring cost | Hosting 200 – 500 EUR/mo | 15 – 40 EUR/user/mo |
| 80 participants / year | ≈ 4,800 EUR | 14,400 – 38,400 EUR |
| Workflows | Tailored to your process | Standardized |
| Subcontractor access | Unlimited, no surcharge | Often billed |
| Accounting/ERP integration | Native possible | Variable |
At 80 participants (internal teams plus subcontractors), SaaS costs 14,400 to 38,400 EUR/year. The custom build becomes cheaper from year two or three, especially if you open access to many occasional subcontractors.
Mini case study
Karim, site manager at a construction company (3 concurrent projects, 40 subcontractors) finds that 2 rework events per month stem from outdated drawing revisions. Average rework cost: 6,500 EUR (labour, materials, delay). That is 13,000 EUR/month, ≈ 156,000 EUR/year of avoidable waste.
He invests 62,000 EUR excl. VAT in an extranet (per-site access + versioning + progress claims + signature) delivered in 18 weeks. Cutting rework by 18% saves ≈ 28,000 EUR/year on this line alone, plus avoided disputes and late penalties. Payback: ≈ 20 months, before counting secured cash flow on progress claims.
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FAQ
Is drawing versioning really essential?
Yes: most costly rework comes from a participant working on an outdated revision. Versioning with distribution alerts removes that risk, for 8,000 to 15,000 EUR excl. VAT.
Can occasional subcontractors be granted access?
Yes, per-site access with invitations lets you open then close rights at no surcharge, unlike per-user SaaS pricing.
Does electronic signature have legal value?
Yes, a signature compliant with the eIDAS regulation is legally binding for subcontracting contracts, minutes and amendments. Budget 4,000 to 9,000 EUR excl. VAT.
How long to deploy?
14 to 20 weeks for the full scope. A first "drawings + site access" package can be live in 8 weeks.
What hosting for sensitive site data?
EU hosting at 200–500 EUR/month covers confidentiality and backups. Subcontractor documents are archived in an auditable way.
Let's scope your project. Tell us your number of sites, subcontractors and priority packages (drawings, progress claims, signature), and we will frame scope and budget. 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.
