After deepening the cellar space to the required depth, we dug out trenches, which we filled-up with 0-4 fraction backfill sand. We have then laid sewer pipeline in the sand. This pipeline is designated to serve technical room which will be established in this space over time. The main sewer pipe which drains the sewage from the entire building also passes under the technical room. A floor drain was planned to be placed in the middle of technical room floor. We installed this floor drain into its final position using dry concrete and connected it to the sewer pipeline pipe.