Using Check in at Work data smartly: here's how it works

What is Check in at Work and who does it apply to?

For construction companies in Belgium, CIAW is a familiar concept. Check in at Work is the legal obligation for attendance registration on the construction site. Every contractor, subcontractor and self-employed person carrying out work on a site with a total project value of €500,000 or more (excl. VAT) must digitally register their presence before work begins.

The main contractor is responsible for the entire chain. That means: not just their own staff, but also subcontractors, self-employed workers and temporary staff. If someone is not registered, the main contractor is liable. Non-compliance puts the main contractor at risk of fines per employee per day.

Working with foreign subcontractors or operating in Belgium as a Dutch company?

Many Flemish construction companies work with foreign subcontractors. Dutch companies active on Belgian sites also encounter this. Both situations require an extra step: the Limosa declaration.

Foreign employers temporarily posting employees to Belgium must submit a Limosa declaration via the official Limosa portal before work begins. This also applies to self-employed individuals temporarily active in the construction sector from abroad. The declaration is made per employee: you specify who will be working, where and for how long. After the declaration, each employee receives their own L1 document with a unique Limosa number and QR code. Every person carrying out the assignment must be able to show this document — to the client and to inspectors.

When CIAW data becomes complex

For the individual employee, checking in is often straightforward: think of registering via an app. The complexity sits one level higher: with the main contractor who is responsible for the entire chain.

On a large site, own staff, subcontractors, self-employed workers and temporary staff often work simultaneously. The main contractor must be able to trust that everyone is correctly registered, including parties they do not work with directly. Agreements about who handles registration must be clear in advance. For foreign workers, the Limosa obligation adds another layer.

Anyone working on two sites on the same day must also register separately at both locations. For companies managing multiple projects simultaneously, that requires a solid overview.

What does having that data in clear view deliver?

CIAW data is more than a registration list. If you actively consult that data and combine it with your planning overview, it provides insight into how the construction site is really doing.

Always compliant with the Check in at Work obligation
The core value of CIAW is compliance. All those present are registered, the chain is in order and during an inspection you can immediately demonstrate who was on site and when. That brings peace of mind and prevents fines.

Insight into attendance on the construction site, anytime and anywhere
Who is present today on which site? How many people are registered on project A, how many on project B? With the right tools you can consult that information at any moment, without having to be physically present. That is valuable for main contractors managing multiple projects simultaneously.

Insight into actual hours worked per project
Check-in and check-out times give a picture of how many hours were actually worked on site. That is useful for project reporting, cost monitoring and invoice verification. Especially on projects with multiple subcontractors, this provides insight into who spent how much time.

Insight into deployment per project and control over planning
Are there enough people present to keep the work on schedule? Does the staffing deviate from what was planned? CIAW data shows how many people were on site on a given day. Combine that with your planning and you quickly see where things are under pressure.

Attendance is one piece of the picture

CIAW data is recorded per site, per day, per person. Most companies use an app or platform for this. But that registration data stands apart from the rest of the operation: planning, project management, vehicle and machine data.

With CIAW you know who is on the construction site. That is valuable. But it does not answer the questions a project manager also has every day: where are the vehicles? Which machines are deployed on which project? Is the equipment in the right location? How much fuel has been consumed? CIAW provides insight into people. A complete picture of the site requires more data.

In practice: CIAW combined with the rest of the operation

Imagine: it is Wednesday morning. A project manager opens their dashboard. CIAW shows 14 people present on the Antwerp site. The planning says 20. Six people are missing.

CIAW data tells you who is on site. But a site consists of more than people. Vehicles, machines and tools move along daily. Only when that data comes together in one platform does the full picture emerge.

With all data in one platform, the project manager immediately sees more. Two vehicles are still on the Ghent site: the crew is delayed. A third vehicle is heading towards Antwerp. One subcontractor is registered at the wrong site. And a machine needed today is at a location where it was not expected until tomorrow. The situation is clear. The project manager can act immediately.

But the value goes beyond a single morning. Anyone reviewing the data over a longer period sees patterns that would otherwise remain invisible. Where is time being lost? Where is more being consumed than necessary? Where does execution structurally deviate from planning? These insights provide the foundation not just to correct the operation, but to make it more efficient and sustainable.

CIAW as part of the complete overview

CIAW data is valuable. But it is one data source. Construction companies that get the most out of it combine attendance data with the rest of their operational information.

GPS-Buddy integrates CIAW into Flowter, the same platform where data on vehicles, machines and equipment comes together. In addition to attendance insights, Flowter provides insight into locations, operating hours, fuel consumption and CO2 emissions per vehicle and per project. Small equipment is also traceable. This creates not just an overview of who is on the construction site, but also how equipment is being deployed and where efficiency gains can be made.

Please note: laws and regulations regarding Check in at Work may change. This article is based on the situation as of May 2026. No rights can be derived from the content of this article. Always consult the official government websites for the most up-to-date information.