For years, the municipality checked whether building work complied with the building regulations: first on paper with the permit application, then with an inspector on the building site. That system had a weak spot: the assessment was mainly about the design, not about what was ultimately built. The Wet kwaliteitsborging voor het bouwen (the Quality Assurance for Building Act), Wkb for short, shifts that inspection to an independent quality assurer who keeps an eye on things during construction, and at the same time strengthens your position as the client in relation to the contractor. In this article you can read what the Wkb involves, which building work it applies to, what changed under private law and what you will notice of it during a renovation.
What is the Wkb and who does it apply to?
The Wkb came into force on 1 January 2024, together with the Omgevingswet (the Environment and Planning Act). The act consists of two parts. The first part is a new system of quality assurance: the check whether building work complies with the technical rules of the Besluit bouwwerken leefomgeving (Bbl, the Dutch Building Decree) is no longer carried out by the municipality, but by a private quality assurer working with an approved instrument. The second part consists of amendments to the Burgerlijk Wetboek (the Dutch Civil Code) on construction contracts, which give consumers better protection.
The quality assurance system is being introduced step by step and for the time being applies only to building work in gevolgklasse 1 (consequence class 1): building work with a limited risk to the surroundings if something goes wrong. This includes, among other things, single-family homes on their own plot, houseboats, holiday homes, simple commercial buildings of no more than two storeys and small bridges for cyclists and pedestrians. Apartment buildings, national monuments (rijksmonumenten) and buildings where many people gather are not included; the municipality continues to carry out the checks there.
Since 1 January 2024 the system has applied to new builds in consequence class 1. For renovations in consequence class 1, the introduction has been phased and postponed several times, so that the construction sector and the municipalities could first gain experience. According to the Rijksoverheid (Dutch central government) and the Informatiepunt Leefomgeving (the government's information point on the living environment), the introduction for renovations has been postponed for the time being and there is no definitive start date yet; the expectation is that the system will apply only to new builds up to and including 2028, with an overall evaluation of the act in 2027. Check the current status on rijksoverheid.nl and via the permit check in the Omgevingsloket (the national environment and planning portal), because the timetable has kept shifting in the past. The amendments to the Civil Code, by the way, have already applied since 1 January 2024 to construction contracts concluded from that date onwards, renovations included; only the stricter duty to warn also applies to older contracts.
The role of the independent quality assurer
If your building work falls under the system, a bouwmelding (building notification) replaces the old omgevingsvergunning (environmental permit) for the technical part. With that notification, which is submitted at least four weeks before the start, you state which quality assurer and which instrument you are using and you attach a risk assessment and an assurance plan. The quality assurer is a certified, independent company that may not be involved in the construction itself. It assesses the design, visits the building site at the moments set out in the assurance plan and checks whether the work complies with the rules: foundations, structure, fire safety, insulation, ventilation.
Once the work is finished, the quality assurer draws up a declaration that there is justified confidence that the building work complies with the rules. That declaration goes to the municipality, together with the dossier bevoegd gezag (the file for the competent authority), with the completion notification, at least two weeks before the building work is taken into use. Without that declaration, the building work may formally not be taken into use. The municipality remains the supervisory authority and can intervene if the quality assurer reports that something is not right. The quality assurers and instruments are listed in a public register kept by the Toelatingsorganisatie Kwaliteitsborging Bouw (the body that approves quality assurers).
For you as the client, this means that someone with expertise is keeping an eye on the building site on your behalf, but also that you hire and pay the quality assurer. In practice, the contractor often arranges this and includes the costs in the quote. Ask about this explicitly, so that you don't see it come back later as extra work.
The consumer file at handover
One of the new rules in the Civil Code is the opleverdossier (handover file), popularly known as the consumentendossier (consumer file). When the contractor reports that the work is ready for handover, they must give you a file containing everything you need to demonstrate that the work was carried out in accordance with the agreements and the rules, and to use and maintain the building. Think of drawings and calculations, a description of the materials and installations used, and information on use and maintenance. This file is something different from the quality assurer's file for the competent authority: the handover file is for you, and it also applies to renovations that do not fall under the quality assurance system.
Please note: this rule is regelend recht (non-mandatory law). The parties may agree in the contract that there will be no file or a more limited one. So check in the quote and the general terms and conditions whether the handover file has been excluded, and ask for it to be included after all if it has. A contractor who refuses to document what they have done is a red flag.
Longer liability for hidden defects
Until 2024, after handover the contractor was only liable for defects that you could not reasonably have discovered at the handover. If you discovered a defect later that you really should have spotted earlier, that was your problem. That has been reversed. The contractor is now liable for all defects that were not discovered at the handover, unless they prove that the defect cannot be attributed to them. The burden of proof therefore lies with the contractor, not with you. For consumers this rule is dwingend recht (mandatory law): the contractor cannot deviate from it in their terms and conditions.
This does not make a careful handover any less important. Walk through the work together, draw up a handover report listing all visible defects and agree a period within which they will be repaired. Anything you do see but do not have recorded is deemed to have been accepted. Defects that only become visible later, such as leaks, cracks or a poorly functioning installation, should be reported in writing as soon as you discover them.
The contractor's duty to warn
A contractor always had to warn you about errors in your instructions, about unsuitable materials that you supply yourself and about inaccuracies in drawings or advice from third parties. What is new is that the warning must be in writing and unambiguous, and that the contractor must point out the possible consequences for the soundness of the work to you in good time. A passing remark on the building site is therefore not enough. If, for example, you want a thinner floor than the structural engineer advises, the contractor must explain the risk of that to you by email or letter. If they do not, they bear the consequences.
The 5% suspension right: only for new builds
There is a lot of confusion about the 5% rule. This rule applies to the construction of a new home commissioned by a consumer, usually via a purchase or construction contract with a property developer. The buyer may place the last five per cent of the contract price in a deposit with the notary instead of paying it to the contractor. That deposit stays in place for three months after handover, so that the buyer can keep up the pressure on the repair of snagging points. The Wkb has tightened this arrangement: between one and two months after the handover, the contractor must ask the buyer in writing whether they wish to keep the deposit in place, and sends the notary a copy of that request. The notary only pays out after three months, and only if they have received that copy and the buyer does not invoke their right of suspension; the deposit is no longer released automatically.
For a renovation, this statutory arrangement does not apply. You can, however, agree something similar: a final payment instalment of, for example, five or ten per cent that only becomes due after the snagging points have been repaired. Put that in the quote or contract before you sign; afterwards, a contractor can no longer be persuaded to agree to it. You can read how to assess such a payment schedule in Comparing quotes: how to read a building quote.
What should you ask your contractor?
- Does my renovation fall under the quality assurance system, and if so, who is the quality assurer? A contractor who regularly builds in consequence class 1 will know this and has regular quality assurers they work with. Ask whether the costs are included in the quote.
- Who submits the building notification and the completion notification? Formally, you as the client are responsible; record that the contractor will take care of this on your behalf and send you copies.
- Will I get a handover file, and what will be in it? Check that the file has not been excluded in the terms and conditions.
- How do you handle warnings and extra work? Agreement: in writing, in advance, with an explanation of the consequences and the costs.
- What guarantee do you give in addition to the statutory liability, and are you insured? Ask about liability insurance and CAR (Construction All Risks) insurance for the work.
- Which general terms and conditions apply? Terms drawn up in consultation with consumer organisations, with an independent dispute resolution scheme, are a plus. Also read 5 tips for choosing the right contractor.
On VerbouwPro you post your renovation free of charge, and contractors from your area respond with a verified profile, KvK (Chamber of Commerce) number and reviews. State in your job description that you expect a handover file and clear agreements about quality assurance; you will then know straight away which tradespeople are already set up for this.