Delivering Sustainable Housing through Material Choice

Abstract

Increasing importance is being placed on sustainability worldwide to limit climate change’s effects. In New Zealand, a sizeable increase in demand for housing is driving a residential construction boom, with new dwelling consents increasing yearly for the last decade. The New Zealand Government’s commitment to sustainability has become legislation through the Climate Change Response (Zero Carbon) Amendment Act 2019. Therefore, the next stage is how the construction industry can limit and reduce its carbon emissions through one of the strategies, namely material choice. This study was intended to examine the influence of various building materials on climate change and to identify how more sustainable home construction and design in New Zealand may contribute to the government’s 2050 emissions reduction targets. A life-cycle assessment (LCA) was used in this study to investigate the global warming potential (GWP) produced by five case study houses and various material options for building envelope components. The study focused on the environmental impact of materials with high usage in industry and potential new materials that have shown an ability to conform to the New Zealand Building Code standards. It was found that case study House 1 (with timber flooring founded on senton piles with concrete footings, a timber frame, plywood wall cladding, and metal roof cladding) and House 2 (with a concrete waffle slab, a light steel frame, masonry wall cladding, and metal roof cladding) had the lowest GWP emissions compared to the other case study houses, with 631.13 and 633.16 kg CO2eq/m2, respectively. However, it should be noted that all the case study houses were not similar in size and design. In addition, the study investigated the different building envelope material options for the foundation, wall cladding, framing, and roof cladding. The study found that some new materials or materials that are not common in New Zealand could be used as an option for the housing envelope by having lower carbon emissions, such as 3D-printed concrete blocks compared with brick and concrete masonry for wall cladding systems.