Drivers and Barriers of Green Roof Implementation in Public Buildings: A Case Study of Nitra, Slovakia

Abstract

Vegetation elements on buildings such as green roofs are increasingly recognized as nature-based solutions to address urban environmental challenges. Green roofs can be adapted to diverse climates and building types. Their implementation in Slovakia has been rising, yet it remains limited in scale and technological ambition. Projects funded from public resources often remain conventional, with rare ambition to implement novel stormwater management systems and solutions that enhance biodiversity. Currently, the majority of investments in green roofs are limited to the private sector, while public institutions lag behind. Thus, public buildings with novel green systems and elements can still be considered non-conventional, innovative, and influential. This study investigates the development of green roofs on public buildings in the city of Nitra, Slovakia, from the first installation in 1992 to recent projects in the 2020s. By systematically mapping all existing public green roofs and conducting qualitative narrative interviews with key stakeholders, this research aims to identify the main motivations, actors, and barriers behind the implementation of green roofs in public investments. The novelty of this research lies in its mixed-methods approach, combining quantitative and qualitative analyses to draw conclusions from a comprehensive dataset. By capturing all existing examples within their spatial and temporal context, rather than relying on a random subsample of case studies, this study provides a highly representative evaluation of green roof adoption. Preliminary findings provide insights into the temporal and spatial diffusion patterns of green roofs in a medium-sized Central European city and highlight the main drivers of public decision-making. The results contribute to a better understanding of how urban sustainability initiatives emerge in public sector contexts and aim to inform policy and planning to initiate and boost more green roof implementation.