Modern architectural practice is competent in examining the implications of new structures operationally, notably in the context of operational energy usage and carbon emissions. Embedded emissions design experience is still limited, despite social trends urging the incorporation of environmental considerations into the design process at the very beginning phases.

The design process is defined in both theoretical and experimental literature as a series of repetitive decision methods that gradually elevate the design to a superior complexity level while decreasing uncertainty. Beginning with the early conceptual phases, when many factors are ambiguous and the design team analyzes a wide variety of strategic and parametric possibilities, and concluding with the project’s completion when the final building eliminates all uncertainty, the design changes with time. If environmental effects are to be successfully included in the early design phase, simpler methods that can deliver higher accuracy while using a few generic parameters are required.

A simple solution can be presented by integrating these two techniques, making embodied carbon data more available and usable for non-technical customers and construction professionals for the early design process with the development of low-embodied carbon buildings.

It is feasible to construct simpler embodied carbon tools, to save time, and this can also deliver enhanced assessment results such as the LCAP tool, which gives more precision in the early design process by utilizing fewer generic parameters [49]. For the secondary building parts and services, a similar approach must be followed, which is now not included in the model, and would assist the ongoing development of the tool. This would include calculating material consumption per square meter of floor space for doors, staircases, heating/ventilation systems, and other construction components. This would enable the tool to learn and expand with these elements, increasing the instrument’s accuracy even further, enabling it to be utilized for later stages of the building’s life cycle.

Generally, for the environmental performance of the product, two methodologies are established, life cycle assessment and carbon footprint; such is the case of building assessment. With the established methodologies, common quantitative claims of life cycle assessment exist in two forms, environmental product declaration (EPD) and product carbon footprint (CFP). For the lifecycle-based quantitative claims, it is necessary for the product to be open to the sources of data, the boundaries of the system, the recycled product’s impacts and the choice of measurement [50]. In the building’s life cycle assessment, two established methodologies play a vital role to achieve the lifecycle-based quantitative claims. As the building constitutes different materials and shows different maintenance requirements in different stages of its life cycle, the EPD and the advancement in the modeling options of the material sources and system boundaries according to region and requirement lead to a detailed life cycle assessment of the building in any stage. The EPD application in the early stage leads to the detailed analysis of CFP in any stage of the building’s life cycle. However, for the EPD to support comparable EPDs, product category rules (PCRs) are considered mandatory to define specific rules for products serving the same function [51]. For the PCRs to develop, ISO 14,025 [52] presents the procedures and content required for a PCR, as well as requirements for comparability. However, standards present a defined set of rules and will not be sufficient for the development of PCRs for every requirement, which can also be called supplementary requirements. In the building sector, several documents and standards have been published other than ISO 14025, such as EN 15,804 [53], EN TR 15,941 [54], EN 15643-1 [55], and many more, which promise to serve the purpose of comparison and comparative assertion, but they also require a certain form of PCRs to carry out the promise. For this purpose, EN 15084 + A1 [53] is presented for the further development of EPDs [56]. With the contribution and collaboration of developers, PCRs are developed according to regions and requirements. Although such developments are the case in Europe or other developed nations, developing nations still fail to understand the concept of EPDs and PCRs.

Construction, maintenance, and demolition trash have become a major source of solid waste for the environment and society in developing and developed countries, due to the tremendous rise of the construction sector globally in recent decades due to population increase; 20–60% of the world’s solid waste stream is produced by the construction industry [57]. Construction-related garbage makes up roughly 20–30% of all solid waste produced in the European Union (EU), 30% in Canada, 29% in the United States, 26% in Hong Kong, and 30–40% in Australia. [58,59,60,61,62]. As a result, while construction contributes greatly to global progress and money, it also has a severe influence on the environment. Waste is sometimes disregarded because it is seen as negligible in comparison to waste generated during operations.

Landfilling and incineration are two typical waste disposal methods that have wreaked havoc on society, both economically and environmentally, by accumulating garbage and exacerbating the problem of global warming by emitting carbon dioxide (CO₂) during procedures [63,64].

Rapid population expansion has accelerated construction operations, resulting in increased trash output and embodied carbon across the phases of an existing building’s lifetime. Demolition operations contribute the majority of the waste, whereas construction trash makes up the smallest portion of the entire waste portion. Despite the fact that the construction stage generates the least waste, it is possible to reduce the waste rapidly and effectively, with the option of better site management and improved information flow and coordination among members of the design team during the design and construction phases. Maintenance waste, on the other hand, has generally gone ignored among the three, despite having a higher potential of embodied carbon content than building waste—almost six times more over 50 years. The durability and quality of materials will dictate how often they must be maintained, replaced, or repaired. Design rethinking and embracing lifecycle thinking are thus critical steps toward reducing waste and maximizing possible recovery.

EOL waste output and related embodied carbon are by far the highest. Because of different sorts of obsolescence or other factors, the destruction of the EOL of the building is sometimes unavoidable. It is possible that the materials or components can be reused or refurbished during lifecycle management, and design-out-waste concepts are employed from the early design stage, preventing landfilling. Furthermore, well-designed and -maintained buildings can survive longer, preserving most of the embodied carbon contained in the construction.

If appropriately collected, handled, and recycled, the wastes created at different phases of a building’s lifetime may be reused and become important resources for the construction industry. The waste can be considered a valuable resource for substituting raw materials and reducing embodied carbon and landfill waste. The role of transportation in embodied carbon’s impacts on waste has been demonstrated. As a result, minor changes in travel lengths may cause the outcomes to worsen. As landfill sites are rapidly filling up and possible new sites for dumping waste are located further away from built-up regions, requiring a longer journey, this is becoming the case. The most essential technique to minimize the embodied carbon in the three stages of buildings is to avoid waste formation so that resources are not wasted, and the environment is not harmed. Addressing waste minimization through design optimization and early stakeholder involvement is key to the strategy's success.