The contract involved reconstruction of the following in the Selgros shopping mall building in Szczecin: the customer entrance hall and connecting hall, expanding the complex with a social and office area, dry storage and modern cooling and freezing storage with specialist sanitary and electric installations. The newly constructed halls were built in the prefabricated concrete mixed structure method with a steel roof. They were fitted with the following installations: sanitary (Geberit Pluvia roof drainage, domestic hot water, fire-fighting water, underslab sewage) and electrical (lightning protection, 230V and 400V power outlets, SAP fire alarm and DSO sound alarm fire protection, LAN structural network, SSWIN burglary and battery alarms, access control, CCTV, LED illumination). The works also included design and construction of a power reserve management system with supplying a 275 kVA power generator and a photovoltaic installation connected to the cooling and freezing systems, allowing for limiting power consumption and CO2 emissions. The low-current electric systems installed in the building were integrated with the existing installations present in the shopping mall. An asphalt surface road and parking array was re-developed on the site as well. All the construction works were carried out in a very short term without the need to stop the activity of the main building of the shopping mall at any time.