Does a permeable sub-base (load-bearing layer) need to be installed with a slope?

A permeable sub-base does not generally require a slope. In technical terms, it is a water-permeable load-bearing layer through which rainwater can infiltrate naturally into the ground.

This natural infiltration costs less than artificial drainage into the surface water sewer system, is ecologically beneficial and supports both the natural water cycle and groundwater recharge. For the system as a whole to provide effective infiltration, the surface covering must have high water permeability. Rubber tiles made from PU-bound rubber granules are particularly suitable for water-permeable systems, including patio tiles, playground tiles and tiles for many other outdoor areas. Suitable surface coverings made from rubber granules achieve a water permeability of 200 litres per hour per square metre or more.