•Precast concrete floor blocks made with crushed bricks and tiles (CBT) aggregate.•Increasing percentage of replacement of natural aggregate with CBT aggregate.•Concrete floor blocks with high replacement percentage meet the requirements. The main objective of this paper is to demonstrate that it is possible to make precast concrete floor blocks with more than 50% replacement of natural aggregate with recycled aggregate made with crushed clay bricks and roof tiles. In first phase of the research, the physico-mechanical properties of concrete with recycled and with natural aggregate were tested. The second phase explored the properties of precast concrete floor blocks. Their geometrical, mechanical, thermal and acoustic properties were determined. Based on experimental research it can be stated that it is possible to make precast concrete floor blocks with recycled aggregate with the fulfilled thermal, cost and environmental requirements.