Very little surface water usually accumulates in covered multi-storey car parks. Here, the focus is more on collecting and draining off dripping water and dragwater, as this can be contaminated with de-icing salts in the colder months of the year. Drainage solutions such as the HYDROline system are ideal for preventing damage to the fabric of the building (e.g. by means of concrete corrosion) and at the same time take into account the low structural heights. The cast-iron linear bar drainage trench with a construction height of just 31 mm is also a perfect choice for use as an evaporation drainage channel.