Final adoption of Book 7 of the Belgian Civil Code and what this means for Construction Contracts

Contract Management Practices Update on Belgian Law in 2026 

In recent years, there has been a wave of new legislation impacting contracts and contractual terms. The Belgian legislator is gradually adopting the different Books of the Belgian Civil Code, and the Belgian Code of Economic Law has been updated several times. These changes affect the way contract terms need to be drafted, not only between companies but also with consumers. 

In this series of alerts, we provide guidance on the drafting and reviewing of standard contracts and contract terms. Our first alert emphasized the importance of drafting fair contract clauses, and our second alert focused on the abolition of the quasi-immunity for auxiliaries (such as directors and subcontractors, with the latter being particularly relevant for construction contracts) and the interaction between Book 6 of the Belgian Civil Code and B2B legislation on contract terms.  

Our third alert gave an overview of the general changes to be brought about by the new Book 7 of the Belgian Civil Code, and our fourth alert focused specifically on the changes to relevant for construction contracts.  

This fifth alert builds on the contents of our fourth alert, now that Book 7 has been finally adopted. 

Alert 5: Final adoption of Book 7 of the Belgian Civil Code and what this means for Construction Contracts 

Compared to the proposal put forward in February 2025, the final, published version of Book 7 does not introduce any major substantive changes relevant to construction contracts. However, it does introduce some important small refinements to the text. 

A more detailed discussion of the key changes for construction contracts that Book 7 brings about can be found in our fourth alert. In this alert we concentrate on the refinements introduced in the final version. 

1. Change of wording: “pre-existing unforeseen circumstances” becomes “pre-existing not reasonably knowable circumstances” 

As mentioned in our fourth client alert, the contractor has the right to renegotiate the contract if it encounters difficulties arising from circumstances that existed prior to the conclusion of a lump sum construction contract, but which were not yet known at the time of the entry into the contract. 

The final text, in article 7.4.8 Civil Code, shifts the test from whether the circumstances were “unforeseeable” to whether the circumstances “could not reasonably have been known” when the contract was concluded. This refocuses the test, putting the emphasis on the contractor’s ability to identify the pre-existing circumstances at contracting.  

2. Concealing nonconformities ensures preservation of employer's rights 

As discussed in our third and fourth alerts, the reform replaces the previous dual-regime system for hidden and latent defects with a single notification rule applicable to both latent and hidden defects. Upon discovering a defect, the employer must notify the contractor within a reasonable time frame or risk losing the right to rely on that defect to claim damages. 

The final, published legislation introduces one important refinement in article 7.4.18 Civil Code: the contractor cannot invoke the “reasonable time” limitation if the contractor was aware of the conformity defect and failed to disclose it to the employer. This creates a meaningful protection for employers. 

3. Firm outer limit to the limitation periods for conformity and stability-threatening defects of 10 years and 3 months 

For conformity defects, the proposal stated that the employer had to bring a claim within two years of notification of the defect, and at the earliest two years from delivery of the works. This limitation period is suspended during good-faith negotiations between the parties and during judicial or contradictory out-of-court expert proceedings. 

The final version of the legislation adds a firm outer limit in article 7.4.19 Civil Code: the employer's right is forfeit in any event 10 years and three months after acceptance of the completed works, regardless of any suspension. 

In addition to ordinary conformity defects, the contractor bears a 10-year liability for defects that threaten the stability or structural integrity of immovable constructions, running from final acceptance of the works, provided the defect is attributable to a culpable failure by the contractor. This regime was already introduced in the proposal. 

However, the final version adds a corresponding outer limit in article 7.4.57 Civil Code to stability-threatening defects: the article mirrors the same outer boundary for the limitation period for liability for conformity defects in article 7.4.19 Civil Code. The employer's right to bring a claim is forfeit 10 years and three months after acceptance of the completed works.  

4. New limitation on invoking nullity for employers 

As discussed in our fourth alert, Book 7 introduces more clearly defined obligations for contractors, including the duty to cooperate with other contractors appointed by the same employer, and the obligation to perform works in accordance with the contract and the employer’s reasonable expectations. 

Where a contractor fails to fulfil these obligations, the employer may apply the remedies under the general rules in Book 5 of the Civil Code. The final version of the legislation adds one important limitation to article 7.4.29 Civil Code: the employer may not invoke the nullity of the service contract for lack of proper understanding at the entry into the agreement because the scope description contains errors or because there are third party claims on the works. 

5. Broadening of contracts classified as sales to include lump sum contracts involving the transformation or demolition of immovable works. 

The final version of article 7.2.2 Civil Code further clarifies the boundary between sales and services contracts in the context of construction. Not only contracts involving the construction of immovable works, but also contracts involving transformation or demolition of immovable works may in certain circumstances be classified as sales in the case of a lump sum contract.  

However, the legislation specifies that even when a contract is classified as a sale, the rules governing defects affecting or threatening the stability or solidity of an immovable work continue to apply to contracts involving its construction, transformation or demolition.  

Timing and application  

• On 16 July 2026, the plenary session of the Belgian House of Representatives approved the final version of Book 7 ('Special Contracts'), introducing it into the Civil Code. 
• The law was published in September 2026 and will enter into force in September 2027. 
• Once adopted, the new provisions of Book 7 will apply only to events occurring after the entry into force of the new legislation. This means that, unless the parties agree otherwise, these new Book 7 provisions will not affect contracts entered into before September 2027, even if events related to these contracts occur after the entry into force of the new Book 7 provisions.   

Conclusion 

The final, published version of Book 7 brings legal certainty regarding a number of important questions for construction contracts. While the changes are relatively small compared to the changes that were originally introduced in the February 2025 proposal, all businesses involved in construction contracts should take note of them. Furthermore, the overall reform is significant and requires careful attention before the changes come into force. 

Some of the new rules are mandatory, while others allow for opt-out or amendment in an individual contract. It is therefore important that all businesses carry out a thorough review of their existing construction contracts and templates in light of the new legislation.  

If you would like to discuss how these reforms may impact your business, or if you need support updating your contracts, our team is here to help. Contact us for tailored advice and guidance.