Déclaration de Travaux and CheckInAtWork: key fulfilments for the construction sector in Belgium

In Belgium, working in the construction sector implies crucial requirements for the parties involved. Namely, submitting the Déclaration de Travaux and declaring your presence on the worksite via CheckInAtWork are the most outstanding obligations. This article therefore aims at exploring each of them in more detail. 

Déclaration de Travaux

What it is and when it becomes compulsory

The Déclaration de Travaux (Declaration of Employment) is a document whose submission is established by Art. 30bis of the Belgian Law of June 27, 1969. Specifically, the normative outlines that certain types of construction works must be declared to the National Social Security Office (ONSS): 

• Works involving the construction, alteration, completion, refurbishment, repair, maintenance, cleaning or demolition of a building or its parts. Among the activities considered, we can therefore mention hydraulics, masonry, carpentry, insulation, installation of prefabricated elements, painting and decorating works.  

• Any operation involving both the supply of movable property and its incorporation into a building. 

From a fiscal viewpoint, the following works must be taken into account: 

• Works regulated by an agreement between a contractor and an entrepreneur worth at least 5,000 € (excluding VAT) involving at least one subcontractor; 

• Works regulated by an agreement between a contractor and an entrepreneur worth at least 30,000 € (excluding VAT) with or without subcontractors. 

• Works classified as particularly dangerous, e.g. involving the use of asbestos. 

In addition to the activities outlined above, Art. 30ter of the same law adds further activities to the scope of application of the Déclaration de Travaux. Specifically, services such as security and surveillance of a building and activities within the meat sector must equally be declared. 

Timeframe for documents submission

The submission of the Declaration of Employment must be carried out by the entrepreneur engaged by the contractor. Generally speaking, the declaration must be submitted electronically to the ONSS before the beginning of the works. However, in case of a temporary construction site or works involving asbestos removal, the deadline becomes tighter. In fact, entrepreneurs must submit the Déclaration at least 15 calendar days prior to the beginning of the activities. Furthermore, works involving asbestos removal must be reported to the Labour Inspectorate of the province where the worksite is located. 

After submitting the Declaration electronically, the entrepreneur receives from the ONSS a declaration’s identification number. This datum must then be shared with all the other parties involved. 

Content of the Declaration

The Declaration of Employment must include the relevant identifying data of the contractors and subcontractors involved. Should additional subcontractors be gradually involved in the project, the entrepreneur must inform the ONSS electronically before the intervention of each subcontractor. At the same time, should subcontractors involve other subcontractors within the activity, they shall duly inform the entrepreneur in writing. 

Other key information to include in the Déclaration is listed below: 

• The ending date of the works, which must be declared on the basis of specific circumstances. Concretely, people and materials involved in the activity are no longer on the worksite and the premises are cleaned. 

• The exact date where subcontractors physically intervene within the worksite as agreed in the contract with the entrepreneur. 

• The exact ending date of the intervention of each subcontractor. 

It is essential to note that not only the person carrying out the work but also the person who has the work carried out acquires the status of contractor or subcontractor. At the same time, each subcontractor becomes a contractor in relation to their own subcontractor. 

In case the Déclaration de Travaux is not submitted or is submitted late, a series of penalties arise. First, the non-compliant entrepreneur shall pay the ONSS an amount corresponding to 5% of the value of the undeclared works. Second, a subcontractor failing to inform a contractor about the intervention of other subcontractors shall pay the ONSS the same percentage of the value of undeclared works entrusted to such subcontractors. 

Additional fiscal obligations

Moreover, when paying a contractor or subcontractor for the works in question, the parties involved must conduct fiscal verifications. In other words, clients, contractors and subcontractors must check whether their (sub)contractors have social security or tax debts. Should that be the case, they must withhold a percentage of the amount of their invoices. Such amount shall then be paid to the competent authority, according to the nature of the debt. In order to ease such verifications, the Belgian Social Security Office offers a dedicated tool on their website. This tool can be used by companies registered in Belgium. Foreign companies, conversely, can conduct the check based on documentation provided by the relevant authorities of their Member State. 

CheckInAtWork

Purpose of the system

Lastly, in case of works in immovable property or the meat sector, foreign contractors and employees must declare their presence at the work site. This shall be done via CheckInAtWork, an online service established by the Belgian Social Security website. It aims at registering the workers’ presence in the places indicated in the Déclaration de Travaux. The two requirements are therefore strictly intertwined and each of them contributes to the accurate reporting of works.  

Going more into detail, registration of presence is obligatory: 

• For employers or contractors working in immovable property; 

• For foreign employees or independent contractors; 

• For any work in an immovable property whose total cost reaches or exceeds the threshold amounts below: 

• €800,000 if works began in the period from April 1st 2014 to February 29th 2016; 

• €500,000 if works began after February 29th, 2016. 

• For any worker in the meat sector. 

Registration requirements

In any of the cases above, registration must be done before the works begin and for each working day. In case of subordinate work, both the employer and the employee are responsible for the correct registration of presence. To facilitate the process, CheckInAtWork is accessible through a variety of channels, such as mobile, desktop, and web. For every registered worker, the following information is stored within the Belgian Social Security archives: 

• The national registration number or the Limosa number (in case of foreign workers posted to Belgium); 

• The identification number of companies or independent contractors; 

• The identification number of the workplace as stated in the Déclaration de Travaux; 

• The exact dates of presence at the worksite. 

Conclusion

Compliance with the Déclaration de Travaux and CheckInAtWork requirements is essential for companies operating in Belgium’s construction sector. These obligations not only ensure transparency and traceability throughout the supply chain, but also help prevent financial penalties. Foreign companies posting workers to Belgium should therefore carefully assess their reporting obligations before commencing any construction project. Proper planning and timely workforce registration thus become key elements of a compliant and efficient cross-border operation.