Decisions made during design, construction and operation phases have effects on the environmental impacts of buildings throughout their life cycles. However, environmental impacts of construction process are often ignored. Construction techniques affect the overall environmental impacts of construction process by determining the materials, the equipment and the labour to be utilized for the constructability, which in return affects the amount of energy use and emissions and construction wastes generated during the construction process. This study proposes a model (environmental assessment of external wall cladding construction, EACC) to assess the effect of external wall cladding construction techniques on environmental impacts during their construction process. In this context, first- and second-level indicators, environmental impact benchmarks and contributing factors were defined and scores of the contributing factors were calculated. The pilot study of the EACC suggests that construction techniques affect not only resource and energy usage, labour health and safety during the construction process, but also reuse, remanufacturing and recycling possibilities of the materials at the end of their useful life.