Building Quality Assurance Act (Wkb)

The Dutch Building Quality Assurance Act (Wkb) changes how construction quality is checked and documented. Where municipalities previously focused mainly on upfront assessment and supervision, an independent quality assurer now plays a central role in Wkb projects. The quality assurer checks whether the building work meets the technical building rules and issues a declaration at the end for the completion notification.

For clients and contractors, the Wkb matters because quality must be demonstrable. The final result is not the only thing that counts. The underlying dossier also matters: risk analysis, checks during construction, correction of deviations, and the information handed over at completion.

The Core: Making Construction Quality Demonstrable

The Wkb was introduced to identify construction defects earlier and strengthen the position of clients. The act places more emphasis on documentation. A contractor must be able to show what was built, which materials were used, and how risks or deviations were handled.

Liability after handover has also been tightened. If a defect is discovered later and is attributable to the contractor, the contractor may remain liable for it. A careful construction and handover dossier is therefore not a formality, but important evidence for both parties.

When Does the Wkb Apply?

The Wkb is being introduced in phases. Since January 1, 2024, the act has applied to new-build projects in consequence class 1. Examples include ground-level homes, small commercial buildings, and simple bicycle or pedestrian bridges. Renovations and buildings with a higher risk class follow later or are subject to different conditions.

Whether a project falls under the Wkb depends on the type of building work, the consequence class, and the permit or notification requirement. In practice, this is often checked through the Dutch Environment Portal or with the building adviser, contractor, or quality assurer.

The Process: From Plan to Completion Notification

In a Wkb project, part of the quality control shifts to an independent quality assurer. The municipality remains the competent authority, but bases the completion notification partly on the quality assurer's declaration.

1. Building plan and consequence class: First, it is determined whether the project falls under the Wkb.
2. Selection of the quality assurer: The client or contractor appoints an independent quality assurer.
3. Risk assessment and assurance plan: The quality assurer describes which risks require extra attention.
4. Checks during construction: The quality assurer checks critical elements and records the findings.
5. Correction of deviations: Deviations must be resolved before a positive declaration can follow.
6. Declaration and completion notification: After completion, the quality assurer issues a declaration if the building work meets the technical building rules.

Note: Without the quality assurer's declaration, the completion notification may be incomplete. That can affect the moment when the building work can officially be taken into use.

What Changes for Clients and Contractors?

1. Stricter liability after handover

Under the Wkb, a contractor may remain liable after handover for defects that were not discovered at handover, insofar as those defects are attributable to the contractor. This makes a clear dossier important: it helps record what was agreed, built, checked, and corrected.

2. The consumer file becomes more important

At handover, the contractor must provide a consumer file. This may include drawings, calculations, materials used, and maintenance instructions. The dossier shows what has been delivered and helps the client use, maintain, or sell the building later.

3. The 5% rule requires active communication

For private clients, the 5% rule remains relevant. The contractor must inform the client in writing and on time about the right of suspension around the deposit held by the notary. If that communication is missing, it can affect release of the deposit.

4. The duty to warn must be taken seriously

If a contractor sees an error or risk in the design, assignment, or instructions from the client, the contractor must give a clear warning. Written documentation prevents disputes afterwards and fits the broader Wkb principle: quality must be demonstrable.

Practical Meaning for Quotes and Contracts

For clients

State in the quote request whether the project falls under the Wkb, who appoints the quality assurer, which documents are expected at handover, and how deviations during construction are reported. Also ask when you will receive insight into the assurance plan and handover dossier.

For contractors

Make clear in the quote which activities, checks, and dossier documents are included. Record who is responsible for the quality assurer, which information the client must provide, and how additional work or design changes are documented. This prevents the Wkb from becoming a point of discussion only at the end of the project.