Explanation about the ventilation:
Before the bathroom renovation, there was a major noise issue. That ventilation you see in the photo is a shared ventilation shaft that connects to our upstairs neighbor's bathroom through a vent grate. So as you can guess conversations, sounds, noises were coming from it. Therefore we basically:
– Removed the old wall-mounted vent grate
– Installed a new ventilation fan in the ceiling (much more effective than the old noisy extractor)
– Connected it to the shaft through the ceiling.
– Lined the entire ventilation box with acoustic insulation material
– Also insulated the walls adjacent to the neighbor's bathroom
by CotaPT