The remarkable growth of the construction sector in the United Arab Emirates (UAE), similar to many fast-growing countries, raised a global interest on the energy impact of buildings. The energy share consumed in buildings stands at a massive 70% in the UAE. The government initiated serval enforcements to curb the related energy usage and CO2 emissions, notably through the energy building code and the minimum insulation values of the building envelope. However, the current construction quality control procedure does not include verification of construction thermal defects, relying solely on specifications and building energy performance simulations, whereas field studies and post-construction status highlight a major energy performance gap -largely due to construction defects. Defects during the construction process are costly but preventable if detected and remediated early enough. Hence, the aim of this study is to identify building defects during construction on selected residential case studies in the UAE through thermography diagnosis. The first target is to identify, categorize and analyze the types of building defects that occur during construction that may have an impact on building energy efficiency. Then, the reasons and causes of such defects are assessed in order to establish early mitigation strategies during the construction process. Several residential construction sites were analyzed with two distinctive and similar results: improper insulation strategies that created thermal bridging between the structure and the walls, and a combination of non-compliant or late design changes.