The literature reveals a large number of past studies conducted to identify the origins of waste. However, the findings of these studies cannot be compared directly, as these studies used different approaches to classify waste origins from construction projects. For instance, some authors classified waste origins based on project level activities. Gavilan and Bernold [
32] classified waste origins under six categories based on different project activities: design, procurement, handling of materials, operation, residual related, and others. A similar approach has been adopted by Bossink and Brouwers [
19], who further extended the list of causes of waste related to aforementioned waste origins at site level. Ekanayake and Ofori [
17] also categorised waste origins into four clusters: design, operational, material handling, and procurement. Soibeiman
et al. [
34] and Pinto and Agopayan [
33] used a different approach to the above and related construction waste to material types such as steel, cement, concrete, sand, mortar, ceramic block, brick, timber, hydrated lime, ceramic wall tiles, and ceramic floor tiles. Moreover, Rounce [
46] pointed out that major construction waste origins are related to the design stage, such as design changes, and variability in the numbers of drawings and in the level of design details, whilst Keys
et al. [
47] classified the origins of design and construction waste under the headings of manufacture, supplier, procurement, designer, logistics, client, contractor, and site management. The latter classification indicates that waste origins are associated not only with project activities but also with project stakeholders. Apart from the above, some researchers linked causes and origins of waste to project life-cycle stages. A study by Graham and Smithers [
35] found that factors causing construction waste span the project life cycle, including design, procurement, materials delivering/handling, construction/renovation, and demolition. This was further confirmed by Osmani
et al. [
36] who stated that construction waste is effectively generated throughout the project from inception to completion, while categorising design-related waste causes into project life-cycle stages. Since life-cycle categorisation of construction waste causes covered most of the issues related to construction waste generation, a life-cycle approach was considered to be the best method for compiling construction-related waste causes in this research. Some studies define the term “project life cycle” from inception to completion [
36], while some studies adopt the concept of cradle-to-grave [
35]. However, the former approach of defining the lifecycle from inception to completion well suits the construction waste definition in this research, as demolition waste is not considered. Additionally, a project life cycle was broadly divided into four stages: pre-design, design, tendering and contract agreement, and construction; and compiled causes of waste mentioned in the literature as shown in
Table 1.
As shown in
Table 1, the current literature provides clear evidence that the causes of waste have either a direct or indirect impact on generating construction waste, and this could arise at any stage of a construction process, from inception to completion. The impacts of these waste causes could vary due to the nature, complexity, size, and stakeholder relationships in a project. To identify the most appropriate waste minimisation approach, it is important to customise the causes and origins of waste particular to each project. There is a general consensus in the literature that healthcare buildings are different and more complex than other buildings [
37]. However, existing research findings are not enough to determine the impact of each waste cause on generating construction waste due to those complexities. The next section explores complexities in healthcare buildings which could impact adversely on construction waste generation.