The contribution contains partial results of the research focused on exploration of impacts influencing the overall amount of costs for construction of blocks of flats in Yemen. These are mainly the following: placing the building in a particular locality, using local building materials and existing assortment of imported building materials (their characteristics and dimensions), using geological research when making design of building foundations, scheduling,etc. The designer must take these impacts into regard when making design of a building to decrease the costs for its construction as well as utilization. The performed research showed that for example by proper foundation in accordance with particular geological conditions there can be achieved a reduction of the overall costs for project construction even by 8.5 %, by proper selection of building material and and its better use ( without excessive waste) up to 5 % of total costs can be saved. The project must be executed in optimum time and using CPM methods up to 2.6 % of total costs for project construction can be saved.