WKB Performance Ladder: equivalence of certificates for risk reduction

January 11, 2023

For use by all quality assurance bodies and instruments

By mid-2023, quality in the building sector will acquire a new dimension through the Building Quality Assurance Act (Wkb). More specifically, the Wkb sets quality requirements for the finished building work, the so-called as-built quality. Independent quality assurance bodies check building work quality using a Wkb instrument, an assessment methodology for the building process, to ensure that it is compliant with the Building Decree. After the Wkb comes into force the Building Decree will be called the Building Decree in the Living Environment (Bbl). If the client also agreed to have private aspects checked, the quality assuring body can include these.

Wkb Performance Ladder

In the preparatory phase of the Wkb, the Netherlands Quality Assurance Association (VKBN) is busy developing the Wkb performance ladder. The Wkb performance ladder is a national, broadly aligned guide so that every quality assurance body in the Netherlands can use the existing quality schemes in the same way for the benefit of uniformity and risk reduction during building work.

Risk reduction with quality declaration

The quality assurer checks the as-built quality in accordance with a risk assessment and an assurance plan. In the risk assessment, the quality assurer determines the probability of a risk occurring during a building process, the extent of that risk and its consequences. This then forms the basis of the assurance plan in which the quality assurance body defines how it will manage the risks. If the building process has proceeded correctly, upon completion the Quality Assurer issues a Declaration of Legitimate Expectation to the municipality, stating that the building work meets the building regulations.

Existing quality declarations, also called conformity declarations or certificates, help reduce risks. They provide legitimate expectation that the subject of certification, a product or process, meets quality requirements. If this is done under accreditation, competence and independence are assured. There are, for example, hundreds of quality schemes in circulation on the basis of which many thousands of quality declarations have been issued. They have been developed over the years by various organisations including KOMOKIWASKHSKG-IKOBSGS INTRON and InstallQ.

Quality assurance bodies can deal with quality schemes in the same way

Ton Jans

Wkb performance ladder for instrument and Quality Assurer

Ton Jans chairs the instrument providers within the Association for Quality Assurance in the Netherlands (VKBN). He sheds light on the significance of the Wkb performance ladder. “The Wkb performance ladder was developed to provide an independent and harmonised valuation of quality schemes in building and installation engineering. Using the Wkb performance ladder, quality schemes can be valued in the same way as risk management measures, even if they differ from each other. The ladder can be used as a ‘reading guide’ by every Wkb instrument and every quality assurance provider so that all quality assurance providers in the Netherlands can deal with quality schemes in the same way and can assign the same value to quality declarations in order to reduce the risk of building defects.”

The Wkb performance ladder distinguishes between conditions applicable to materials and products and conditions applicable to the building process. The highest step on the ladder can be reached when both groups of conditions are met. This provides the highest level of risk reduction. Another advantage of this is that the valuation of the quality schemes in the Wkb performance ladder, mean the Quality Assurer can safely spend less time on inspections. After all, that specific building product or process has already been assessed once before as part of the certification, and the quality declaration issued by the certification body has a certain reduction value on the rungs of the ladder.

Elphi Nelissen, chairman Wkb review committee

Independent and objective valuation of quality schemes

The Wkb performance ladder has an independent and national Wkb review committee made up of all parties concerned. Elphi Nelissen chairs this committee. She has a formidable reputation as an expert in sustainable building and circularity and was, among other positions held, a professor at TU Eindhoven’s faculty of structural engineering. Besides this, she also held various other positions, such as being a member of the Building Agenda task force. “Our task as Wkb assessment committee is to establish the assessment framework and the valuation of the quality schemes in the Wkb performance ladder. We record this value assessment in an independent objective report,” Elphi Nelissen explains. “The performance ladder is made available free of charge for the benefit of the market by means of an open online platform, the Wkb performance website. “The performance ladder is made available free of charge for the benefit of the market by means of an open online platform, the Wkb performance website. The Wkb review committee reports annually and publishes its report on this website.” Elphi Nelissen recognises the sizeable benefits of the ladder: “I expect the Wkb performance ladder to make a substantial contribution to the process of quality assurance under the Wkb. How wonderful it is when all quality assurance bodies and instruments deal with risk management in the same way on the basis of equivalent and objective assessment of quality schemes. The quality assurance body can assume an established degree of risk reduction in the overall building process of a specific quality scheme focused on a specific product and/or process. Incidentally, the certificate holder does not need to do anything to get his/her certificate on the ladder. Existing certificates based on the quality schemes of affiliated (quality) marks are in any case valued on the Wkb performance ladder.”

What changes for the builder under the Wkb?

The builder has traditionally been concerned with quality and will often use certified products or engage subcontractors working in accordance with certified processes based on quality schemes. Under the Wkb these certificates are going to play a greater role in relation to risk reduction. The builder must meet the legal requirements and for this purpose must submit information (certificates, photos during building, et cetera) to the quality assurance body. The change to the Civil Code, which is to come into effect at the same time as the Wkb, states that if the client can prove there are defects after completion, the contractor is liable unless proof is given that it is not the contractor’s fault.
Being a certificate holder will help the contractor to manage the applicable burden of proof.
Elphi Nelissen notes another development: “The activities of the quality assurer contribute positively to the builder’s quality management. Certainly when it concerns demonstrating quality. That has considerable consequences for business operations.” She has a tip for the contractor: “Start preparations on time and make sure the quality of the building process is carefully recorded. This will ensure liability is well-managed and that you prevent problems arising after completion.”


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