Certificates and memberships


The Forest Stewardship Council (FSC) is an international, non-profit, multi-stakeholder organization established in 1993 to promote responsible management of the world’s forests. The FSC does this by setting standards on forest products, along with certifying and labeling them as eco-friendly.


The Program for the Endorsement of Forest Certification (PEFC) is an international, non-profit, non-governmental organization that promotes sustainable forest management through independent third-party certification. It is considered the certification system of choice for small forest owners.

VGO — keur in the Netherlands

VGO-keur (Quality Assurance Certificate in the Netherlands) is the first and only independent quality rating/grade by which real estate managers provide assurance about the quality and stability of a maintenance company and its products and services. In addition, VGO certifies that the company delivers results-oriented property maintenance. VGO-keur is managed by the VGO Foundation.

VCA in the Netherlands

VGM Checklist Contractors. VCA stands for Safety, Health, and Environment (VGM-Veiligheid, Gezondheid en Milieu) Checklist Contractors (Aannemers) and is designed to help companies work safely and reduce the number of accidents.

Client feedback

Tell us what you think

Business feedback, comments, hints, insights, anything you think is important and that you are convinced we should know about.

Read what people are saying

Rogier van der Heijden

Querko heeft bij ons een dakopgang en groot dakterras (70m2) gerealiseerd. Ik ben zeer tevreden over hoe alles verlopen is. We zijn altijd goed op de hoogte gehouden van vorderingen en verwachtingen. We zijn betrokken bij de keuzes die gedurende het project nog gemaakt moesten worden. En misschien wel het belangrijkste; een probleempje dat nog na de oplevering aan het licht kwam, is zonder discussie of wat dan ook, zeer netjes opgelost. Ik zou Querko hier om zeker aanraden.

Carrie Ballard

Working with QUERKO was a positive experience. The organization is set up to make a difference in the world via its work—not just sustainable and ecologically advanced buildings, but positive impact on people, wildlife, and planet. Their founding mission carries over to their business relationships. The manager I worked with was kind, professional, committed, and fair. I could not have asked for a better working relationship—if you can work with them, do it. You will not regret it!