This report will be on Hotel Mega Anggrek Extension, an expansion building next to the previous Hotel Mega Anggrek building, located in West Jakarta. This project belongs to PT Purosati Ekatama, a hotel company which operates a hotel chain. The contractor for this project is-PT. ANDALAS SURYA AGUNG. The purpose of this project is mainly to fulfill the increasing demand of occupancy at this hotel. Hotel Mega Anggrek Ext. is built on strategic place. It is located between West, Central, and South Jakarta, with the Jakarta-Merak toll-road and main street nearby. It means that the hotel is accessible from inside and outside the city. The hotel is also near to business and entertainment centers. This hotel building is a middle-rise building. There is an outdoor swimming pool at the third floor of the hotel. Pre-stressed concretes are applied on the structures to hold the load from the swimming pool. The report only covers some part of the building construction process. It was written after 170 hours of observation on the site. The data are collected through interview with the supervisors and workers, and direct observation. The parts of the information that covered in this report are the project details, project organization, construction of concrete beams and columns, and pre-stressed beam. Further information about The Hotel Mega Anggrek Ext. construction may be read on this report.