In the process of assessing a building's overall energy performance, airtightness is an essential factor for enhancing energy efficiency, maintaining occupant comfort, and promoting environmental sustainability. Airtight buildings significantly reduce involuntary air transfers through the envelope air leakage, resulting in massive savings in heating and cooling needs, energy consumption, and cost of operations. The current study examines the airtightness of several rooms within five recently constructed buildings in Morocco's semi-arid region. Those buildings are recognized for their special designs and use of local building materials and will be modeled in a future study dedicated to the overall performances of these buildings. This research includes performing field tests using blower door testing (BDT) to assess and evaluate the building's airtightness and determine the air leakage rate that will be considered in the model. This study provides information regarding the significant impact of building materials on the airtightness levels of the buildings.