Strong (circular) together!

Inspired by the strict requirements of the Flemish government for the office section, Befimmo extended the circular approach for the entire ZIN project. By encouraging its partners and (sub)contractors to obtain C2C certification, Befimmo has been a pioneer in making the construction sector greener and more sustainable. Below it is introduced some of the many partners and (sub)contractors who joined forces to reach the goal together.


Cradle to Cradle Certified® (C2C) aims to create a fully circular economy by using products that can either be reused endlessly or disassemble easily. This means that it goes a lot further than just recycling. Furthermore, the use of safe and clean materials, renewable energy, sustainable water management and social justice, are also essential pillars for a fully circular economy. The goal of this certification is to make the world better than it is today.

Learn more about C2C here.

World Premiere

Eribel developed circular doors specifically for ZIN. They were awarded with a Cradle to Cradle Certified® Bronze product version 4.0 in June 2023. Eribel was the first company in Belgium, and the only manufacturer of interior carpentry in the world, to obtain C2C certification according to the new stricter 4.0 standards. This means not only that the doors are made from reusable, safe and clean materials, but also that the manufacturing  relies on renewable energy, sustainable water management and social justice. This is a real achievement, given the complexity of the product’s manufacturing process.

Sustainable waterproofing

In order to protect ZIN from any future unwanted water infiltration, Derbigum provided a sustainable and circular waterproofing of approximately 50,000 m2. As the second company in Belgium for bituminous products in the roofing segment, Derbigum NT received Cradle to Cradle Certified® Bronze version 3. By recycling construction sites, waste and old roofing membranes and regrinding them before putting them back into the manufacturing process, you can create a sustainable waterproofing system that consists of 20% recycled bitumen (or asphalt).

Zin - Circulair Membraan

Extraordinary drywalls

In June 2022, Knauf was awarded with the Cradle to Cradle Certified® Bronze version 3.1 for the drywalls manufactured in Engis. This makes Knauf the only Belgian manufacturer (large industrial) to have this label for plaster materials such as MP 75. These plaster materials are used as an intermediate layer in the finishing of indoor walls and ceilings. Used especially to smooth out irregularities in the substrate and obtain a flat surface for subsequent finishing layers. To this end, Knauf recycles and upcycles plaster waste from its construction sites.

Step by step

Betesco, a subsidiary of the company Declercq Stortbeton, specialised in tailor made concrete stairs. Nevertheless, the firm supplied precast concrete stairs for ZIN, and received Cradle to Cradle Certified® Silver version 3.1 in May 2021.

Elegant facades in all respects

As one of the biggest players in the field of architectural facade design, production and installation, Kyotec Group received Cradle to Cradle Certified® Bronze version 3.1 for their aluminium facade outlines. These played a prominent role in ZIN’s appearance back in October 2022. This certification applies to both the open/ fixed window frames (with optional blinds) and the polypane glazing.

First circular concrete pour in the Benelux

For the reconstruction of ZIN, CCB Concrete transformed and used about 30,000 tons of old concrete. For the process of transforming rubbles from the old WTC towers into new, high-quality concrete for ZIN, CCB Concrete received Cradle to Cradle Certified® Silver version 3.1. The circular concrete was reused in ZIN as a full load-bearing floor slab. The first C2C-certified circular concrete pour in the Benelux took place on Friday, June 11, 2021. Curious about how that went? Read it here.