# Space Efficiency in European High-Rise Timber Buildings
## 1 Introduction
[PERSON] [47] investigated space optimization in hotels, highlighting the advantages of focusing on spatial efficiency. [PERSON] [48] explored the structural and load-bearing aspects of extruded-form skyscrapers, noting that the service core space expands with tower height and finding no relationship between materials and space efficiency. [PERSON] [49] conducted a stakeholder assessment to improve regional and spatial effectiveness in city planning. [PERSON] and [PERSON] [50] proposed a four-stage construction model that considers the effects of digitalization on interior space demands and availability. [PERSON] and [PERSON] [51] explored lease span and corner patterns in tall towers, concluding that corner cuts have minimal effect on spatial efficiency. [PERSON] et al. [52] developed a freeform design for cold climates, increasing solar gains with minimal impact on spatial efficiency. [PERSON] and [PERSON] [53] examined space utilization in high-rise office construction, focusing on the effects of load-bearing and core configurations. [PERSON] et al. [54] studied the connection between space optimization and overall costs in tall office structures, demonstrating that higher spatial efficiency significantly aids in meeting indoor environmental comfort goals. [PERSON] and [PERSON] [55] assessed space efficiency in multi-use tall edifices, emphasizing the importance of ideal structural systems and designs in improving space use. The literature review indicates that the existing academic research inadequately addresses spatial efficiency in high-rise timber towers in Europe, which hosts most of the timber towers globally. To bridge this knowledge gap and better understand European trends, based on insights from 56 towers, this paper evaluates space efficiency by examining essential architectural and structural components in modern high-rise timber towers in Europe. The description of tall or high-rise towers remains unclear, as there is no global criterion for their height or number of floors. The classification of a structure as 'tall' or 'high-rise', particularly in the context of wooden projects, is still a matter of debate. However, within this discourse, a 'high-rise timber building' is typically described as a structure with eight or more stories [56]. Due to the focus of the study, proportional evaluations of key building zones like the service core were used, without considering the floor area dimensions and building size of the case study towers and structural elements such as columns. This study aims to understand the influence of various planning factors on space efficiency, having four main aspects. These aspects are critical architectural design factors including function, core arrangement, and form; primary structural design considerations including material and system; and spatial efficiency, and the correlation between this efficiency and the aforementioned design factors. This comprehensive analysis, reflecting the latest developments in these construction applications, aims to provide insights for more informed decision-making in the planning of future wooden construction in Europe.