To date, in the literature, there has been no study on the comparison of hybrid (timber and concrete) buildings with counterparts made of timber and concrete as the most common construction materials, in terms of the life cycle assessment (LCA) and the carbon footprint. This paper examines the environmental impacts of a five-story hybrid apartment building compared to timber and reinforced concrete counterparts in whole-building life-cycle assessment using the software tool, One Click LCA, for the estimation of environmental impacts from building materials of assemblies, construction, and building end-of-life treatment of 50 years in Finland. Following EN 15978, stages of product and construction (A1–A5), use (B1–B6), end-of-life (C1–C4), and beyond the building life cycle (D) were assessed. The main findings highlighted are as following: (1) for A1–A3, the timber apartment had the smallest carbon footprint (28% less than the hybrid apartment); (2) in A4, the timber apartment had a much smaller carbon footprint (55% less than the hybrid apartment), and the hybrid apartment had a smaller carbon footprint (19%) than the concrete apartment; (3) for B1–B5, the carbon footprint of the timber apartment was larger (>20%); (4) in C1–C4, the carbon footprint of the concrete apartment had the lowest emissions (35,061 kg CO₂-e), and the timber apartment had the highest (44,627 kg CO₂-e), but in D, timber became the most advantageous material; (5) the share of life-cycle emissions from building services was very significant. Considering the environmental performance of hybrid construction as well as its other advantages over timber, wood-based hybrid solutions can lead to more rational use of wood, encouraging the development of more efficient buildings. In the long run, this will result in a higher proportion of wood in buildings, which will be beneficial for living conditions, the environment, and the society in general.

Space efficiency is one of the most important design considerations in any tall building, in terms of making the project viable. This parameter becomes more critical in supertall (300 m+) residential towers, to make the project attractive by offering the maximum usage area for dwellers. This study analyzed the space efficiency in contemporary supertall residential buildings. Data was collected from 27 buildings, using a literature survey and a case study method, to examine space efficiency and the main architectural and structural design considerations affecting it. The results of this research highlighted that: (1) central core was the most common type of design parameter; (2) prismatic forms were the most preferred building forms; (3) the frequent use of reinforced concrete was identified, compared to steel and composite; (4) the most common structural system was an outriggered frame system; (5) the space efficiency decreased as the building height increased, in which core planning played a critical role; (6) when building form groups were compared among themselves, no significant difference was found between their effects on space efficiency, and similar results were valid for structural systems. It is believed that this study will help and direct architects in the design and implementation of supertall residential projects.

Purpose: This study examined data from 13 international tall residential timber building case studies to increase our understanding of the emerging global trends.Design/methodology/approach: Data were collected through literature surveys and case studies to examine the architectural, structural and constructional points of view to contribute to knowledge about the increasing high-rise timber constructions globally.Findings: The main findings of this study indicated that: (1) central cores were the most preferred type 10 of core arrangements; (2) frequent use of prismatic forms with rectilinear plans and regular extrusions were identified; (3) the floor-to-floor heights range between 2.81 and 3.30 m with an average of 3 m; (4) the dominance of massive timber use over hybrid construction was observed; (5) the most used structural system was the shear wall system; (6) generally, fire resistance in primary and secondary structural elements exceeded the minimum values specified in the building codes; (7) the reference sound insulation values used for airborne and impact sounds had an average of 50 and 56 dB, respectively.Originality/value: There is no study in the literature that comprehensively examines the main architectural and structural design considerations of contemporary tall residential timber buildings.

As a result of increasing urbanization, the need for sustainable housing, e.g., tall (over eight-story) timber apartments, is increasing in Finland. Leveraging the experience of key Finnish professionals plays a significant role in the transition and expansion of sustainable timber housing as an essential part of the forest-based bioeconomy. This interview-based study will serve to fill a gap by examining the views of key professionals with experience in tall timber residential construction, using Finland as a case study. The 21 interviews primarily highlighted that: (1) the construction cost was the most important parameter affecting the architectural and structural design; (2) the most critical consideration influencing the overall design was reported to be the structural system selection and structural design, followed by city planning and client control; (3) key professionals assessed the building’s form and the main dimensions of the building’s mass as the most significant parameters affected by timber construction; (4) the main structural considerations that needed to be developed for tall timber housing were the bracing solutions and fittings, the structures of the intermediate floors, and load-bearing vertical/partition structures; (5) construction preconceptions, the lack of cost-competitiveness, and the lack of construction expertise/actors were considered to be major obstacles; (6) the most important parameters for the future of tall timber apartment buildings were reported to be education, timber construction marketing and public awareness, land delivery conditions, the unification of public administration, and financial support; (7) tall timber building design was reported to be a complex subject that requires close collaboration, especially between the architect, the structural designer and the wood supplier. This paper will help us to understand the boundary conditions affecting the design, the development needs in solutions, the importance of design parameters, the design parameters affected by timber construction, and the prospects, measures and obstacles to tall timber apartments from the perspectives of key Finnish professionals, thereby aiding the sound planning and development of tall timber housing projects.

This paper examined wood preservation practices and outlook considering climate change from the perspective of Finnish experts through interviews. Key findings highlighted that: (1) pressure impregnated wood will continually evolve and secure its market, and it seems worthy of developing modified wood products, especially with the increasing attention to recyclability and lifecycle concepts; (2) demand for highly processed surface treatment products is high; (3) opportunities for more sustainable and environmentally friendly wood preservation methods, and thus production volume will increase in the future; (4) increasing mold problems in Finland due to climate change make surface treatment more important than ever; (5) demands for fire protection treatments are increasing, but fire testing fees and processes have slowed product development; (6) although the possibility of the spread of termites triggered by global warming to Finland seems to be a future scenario, this issue needs to be considered in products exported to hot countries; and (7) preservatives have become more critical to protect untreated wood from the adverse effects of climate change. It is believed that this study will help accelerate the transition of innovative and environmentally friendly wood treatments on the Finnish market, thereby promoting the use of wood in the building construction industry.