Post war heritage and life cycle assessment: conversion of a school into dwellings versus demolition and building new

Because nowadays dwellings become more and more energy efficient, it is besides optimizing the energy efficiency of a building also important to consider the role of the materials used for the construction of the building. This is especially important when new buildings are compared to rehabilitated buildings. A case study, an old Photography school in the post war neighbourhood of Mariahoeve, is chosen as a design project for the conversion of a post war heritage building into dwellings, in order to compare the environmental impacts of conversion with demolition and building new. Life cycle assessment (LCA) is the method used to address the environmental impacts of products and buildings. It models a building’s technical life cycle, documenting energy and material flows during its lifetime and assesses the associated environmental burdens. A few examples of these impacts are global warming potential, waste disposal and nuclear waste. The Life Cycle Assessment is performed with the program Impact, chosen after a comparison between different LCA tools. Heritage assessment is performed in order to analyse the cultural significance of the building. The heritage assessment results in attributes (=What is heritage?) and values (Why is it heritage?) of the building. The impact on the attributes is minimalized during the design phase, finding a balance between the design of a new function, the environmental impact and the cultural significance of the building. Results show that this particular conversion project is more environmental friendly than demolition and building new. A simplified Life Cycle Assessment is a useful tool during the design stage to choose between different design options and is helpful to consider the decision between conversion or demolition and building new.