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Sustainable Conversion of Existing Buildings

One of the great challenges to achieve long term sustainability consists of converting our existing building stock to a sustainable state. This is often complicated by existing managerial, economic and physical structures that do not let themselves be converted easily.

The Government Building Agency (Rijksgebouwendienst) of the Netherlands commissioned Oneplanetarchitecture institute (OPAi) in cooperation with Except to perform a study about this issue. 30 buildings were investigated for the first part of the study. The result was a functional tool for effective, communication and management of conversion projects. The study was subsequently trialed on five example buildings.



The team developed a methodology that performs the following functions:

  • Streamlines communication between client, designer, consultants and builder
  • Presents a clear approach method to evaluate the different possibilities and stadia of conversion
  • Allows for integrated, innovative and progressive solutions that interact with urban, social, financial and physical parameters
  • Creates an easy to understand communication tool for all parties involved

The approach creates four categories of evaluation. These are nested in functionality. This allows a clear phasing and selection:

A- User & Management
B- (partial) Systems & Devices
C- Structure & Spatial Configuration
D- Integrated Solution

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It subsequently measures the resulting performance in the following categories:

  • Energy (EPBD) performance
  • Flexibility
  • CO2 emissions
  • Financing & Management
  • Health & Quality

Conversion Projects:
After a quick-scan of 30 buildings, five buildings were selected, for which comprehensive re-development schemes were developed. The buildings were selected for their diverse typologies. They consist of:

  • A typical 60's urban office block (5 stories), empty at time of study.
  • A large prison complex, built in various era's.
  • A large monumental government building
  • A '70s office block in the Hague
  • A '70 standard typology block, renovated in the '90s


The communication tool developed allowed clear communication about various stages and approaches of intervention. Some buildings were only energetically optimized, while others had complete restructuring and reprogramming concepts applied, including partial privatization, urban integration, reconfiguration, zero carbon and autarktic conversion options.

We continue to refine the methdology developed, study and design various approaches to converting our existing building stock.

Conversion of existing buildings to sustainable buildings
Example usage of phasing tool
Raamwerk CO2 reductie diagram
Selection of the 30 buildings studied
Raamwerk CO2 reductie diagram
Example project: Korte Voorhout

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