Environmental Impacts of Multi-Storey Buildings Using Different ...

- 25 -4 The Buildings4.1 Construction Materials for Commercial BuildingsMost commercial buildings tend to make extensive use of steel, glass, and concrete materialsin construction, all of which can be energy-intensive to produce, via processes that have thepotential to cause adverse environmental impacts and utilising resources that are in shorteningsupply.However, recent developments in wood technology and engineered timber products, seismicand acoustic design, fabrication and construction techniques have enabled timber to beutilised much more extensively for the basic structure of medium-rise, multi-storey buildings,such as a typical ‘down-town’ office block.While there is a tendency for commercial buildings to be labelled according to the mainmaterial used for their sub-structure and super-structure, the vast majority of buildings use alarge number of different materials, from a variety of sources, both national and international.From a materials perspective, a building becomes a very complex system and it is often notimmediately clear which materials or combinations of materials provide the bestenvironmental performance (in terms of life–cycle energy use and GWP, for example). Whileconscious of these limitations, this report will retain this labelling system as it is currentpractice.Studies have indicated that typically structural components account for between 16 and 65per cent of initial embodied energy (Aye, Bamford, Charters, & Robinson, 1999; Cole &Kernan, 1996; Oppenheim & Treloar, 1995; Treloar, Fay, Ilozor, & Love, 2001). Hence,when considering the environmental impacts of building materials, the structural componentsused in a building are of significant importance.This report emphasises alternative structural design options where the predominant structuralmaterial is either concrete, steel or timber.4.2 Building DesignThere are two main aspects in the design of a multi-storey building. The structural designconsiders all the main structural components - the skeleton - including the foundation, thebeams, columns, external walls, as well as the internal flooring system and roof structure.The architectural design provides the external cladding including windows and louvres,internal walls, insulation, etc.. In some areas, the distinction between structural andarchitectural design is not clear cut and there can be considerable overlap; changes to thestructure often enforce changes to the architecture and visa versa meaning any final design istherefore the result of an iterative, developmental design process.The design of the four case study buildings covered by this report was the combined output ofstructural engineers and architects, working together.The case study buildings analysed in this research are based on an actual building, a new sixstorey,4,247 m 2 (gross floor area) (3,536 m 2 net usable area), science laboratory for the