Presence registration on construction sites: the rule, and the geolocated clock-in that fits it

On a building site, knowing who was present and when isn't only about organisation. Above a certain value it's a legal obligation in Belgium. Plenty of contractors half-know the rule without knowing where the threshold sits or how far their responsibility runs. Let's set it straight, then look at how an internal geolocated clock-in fits alongside that obligation.

What the law says

Electronic presence registration on a site — the official system is called Checkinatwork, run by the social security office (ONSS/RSZ) — becomes mandatory as soon as the total value of the immovable works reaches or exceeds €500,000 excluding VAT. That threshold applies to every site started on or after 1 March 2016 (it was previously €800,000).

In practice, every person working on the site must have their presence registered. If the threshold is reached during the works, the ONSS notifies all the parties involved. Registration stops at the provisional acceptance of the works.

Who it concerns

The obligation isn't only on the main contractor. It covers every party declared on the site — including subcontractors and, where relevant, the architect acting as works supervisor. Each one stays responsible for registering the presence of their own workers. On a multi-company site, it's a matter of coordination, not an isolated formality.

Internal clock-in and official declaration: two different things

Worth being clear about: the Checkinatwork declaration is an official step towards the ONSS. An internal clock-in tool does not replace it. What it does answer is a different, equally concrete need: keeping your own reliable, time-stamped record of who was on which site.

That's where a geolocated clock-in earns its keep. In Voilo, your crews clock their arrival and departure from the mobile app, with precise geolocation (3 to 5 metres under normal conditions) and tolerance zones you set per site. You get a full history of presence and movement, plus alerts for absence or lateness. (This feature is part of the Enterprise plan — you can compare the options on our pricing page.)

Why it pays off, beyond the obligation

A reliable attendance record does far more than satisfy a social-security check:

• it feeds payroll and time-based billing without re-keying or paper timesheets;
• it gives you the real labour cost per site, useful for your next quotes;
• it documents your activity in case of a dispute or an inspection.

And because it all sits in one tool, a site's hours flow naturally into the invoice sent to the client — over the structured network, as our Peppol guide explains. For the strictly legal side (thresholds, declarations, special cases), the ONSS and the federal employment service remain the reference.