## 1 Introduction
Therefore, the calculation of building stocks can be conducted using the spatial model in GIS, confirmed by previous studies (Table 1). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**References** & **Aim** & **Scope** & **Data Sources** & **Method** & **Time Span** &
\begin{tabular}{c} **Embodied** \\ **Energy/LCA** \\ \end{tabular} \\ \hline
[64] & Quantify and map the in-use structural bricks & Three cities &
\begin{tabular}{c} GIS map, building types, footprint perimeters, relevant height, historical landscape characterization, ordnance survey \\ \end{tabular} & Bottom-up approach & Yearly & Yes \\ \hline
[65] & Assess GIS-based MFA & \
\begin{tabular}{c} GIS map, Material \\ resources to promote urban mining \\ \end{tabular} & One city &
\begin{tabular}{c} GIS map, footprint \\ Flow Analysis \\ \end{tabular} & Bottom-up approach & Yearly & No \\ \hline
[66] & Quantify and map embodied energy and urban material stocks & One city &
\begin{tabular}{c} GIS map, footprint \\ perimeters, relevant height \\ \end{tabular} & Bottom-up approach & Yearly & Yes \\ \hline
[67] & Quantiy and map urban material stocks & One city &
\begin{tabular}{c} GIS map, Google Earth, \\ U.S. Environmental \\ Protection Agency, building models, design codes, manufacturer’s product data, US DOE \\ \end{tabular} & Bottom-up approach & Every two years & No \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Previous research papers on mapping and quantifying the urban building stocks and specific building materials (i.e., steel, concrete, and brick) using GIS technology. According to Table 1, the previous papers used the bottom-up approach and concentrated on mapping and quantifying the building stocks in the urban scope with a time dimension. The bottom-up method emphasises gathering the weight of construction materials for entire buildings and a small range of areas. This approach utilises typology to show the architectural complex [69]. The data resources from previous studies seem to be varied, but all the researchers used GIS to conduct their research. GIS was applied in the previous studies due to the more accurate product information they could collect as the tools combine map, space, and time aspects to produce definite results. With accurate product information, the previous studies could expand their scope of study to include the embodied energy of urban construction stocks. However, to present a comprehensive evaluation of the potential environmental effects of a particular material or product in urban mining, it is required to integrate the life cycle assessment, urban building stock model, and energy requirement model. In addition, among the previous papers, only one study [64] focused on a specific construction product, while the others [65; 66; 67; 68] aimed to map and quantify the material weights and volumes in the urban areas. GIS allows people to make better strategic decisions using geography, which can be simply described as capturing, analysing, and presenting information on a map. Although the application of GIS has been started in the building industry, the use of this tool in expanding the context of the environmental assessment of specific building products is still limited. The majority of papers took a bottom-up approach to quantifying urban building stocks, focusing on material weight or volume rather than specific construction products such as steel. Although steel products have a high recovery rate for recycling, there is a lack of studies on quantifying steel products. Due to the manufacture of new steel that will generate carbon emissions, the global warming potential (GWP) values in the production and recycling stages of the specific metal products were the focus of this research. Therefore, three different types of particular steel roofing and metal cladding products, long run roofing profiles with seven ribs and five ribs and a tray roofing profile with a pan width of 450 mm, were analysed in this paper.