Net Apartment Area Efficiency in Finnish Mid-Rise Apartment Blocks in Timber

Abstract

In residential construction, clients often seek apartments that are efficient in terms of sellable area so as to ensure economic viability. Using a case study method, this study examines the impact of structural and architectural design features on net apartment area efficiency (NAAE) in fifty-five Finnish mid-rise apartment blocks in timber. In this study, NAAE was defined as the ratio of net apartment area to gross floor area, and the computation of net apartment areas adheres to the Finnish standard SFS 5139. The data was gathered from buildings constructed between 2018 and 2022. The main results of the research were: (1) NAAE ranged from 62.3 to 82.8 per cent and the average was 74.4 per cent; (2) buildings constructed using the 2D and 3D construction methods had an average NAAE of 77.4 per cent and 72.6 per cent, respectively; (3) variations in timber-based shear wall products do not notably impact NAAE; (4) the best average NAAE was achieved with the central core type, followed by the peripheral core type; and (5) the highest average NAAE was attained with a corridor configuration of peripheral + multi, followed by central + multi. This study offers assistance in comprehending design choices related to both structural and architectural aspects, with a focus on NAAE in particular.