Re-Use of timber construction elements for new houses: Approaches and a case study from Austria

Abstract

The AEC (Architecture-Engineering-Construction) industry, a major contributor to greenhouse gas emissions, seeks to reduce the carbon footprint of building activities. This study presents an approach to re-use components from surplus or disassembled prefabricated timber houses, which have been common in the D-A-CH region for decades. These structures consist of modular parts that enable quick assembly but often fail to reach their intended 100-year lifespan due to changing occupancy needs or outdated designs. Consequently, many functional buildings end up as waste. We propose careful disassembly, necessary updates (e.g., thermal, and acoustical performance), and incorporation into new architectural plans. Our research aims to assess the re-use potential of timber-frame prefabricated buildings, focusing on feasibility, obstacles, necessary updates, architectural utilization of existing components, and the extent of re-used designs. We employed a multifaceted methodology, analysing prefab houses from various companies to create a manufacturer-neutral database of construction elements. Additionally, we involved architecture graduate students in a design studio to utilize this database for a new building complex in a challenging suburban site in Vienna, aiming to maximize the use of existing components. Results indicate a significant percentage of re-used components in the designs, along with cost estimates and assembly instructions for different manufacturers' components. Despite challenges related to liability and performance validation, this approach offers a viable path toward increased circularity in small-scale prefab buildings.