Permeable Concrete
Also known as pervious or porous concrete
Permeable concrete, is a robust, easy to install, sustainable building material.
It is a highly porous concrete, which allows water to pass directly through the base layer of the concrete into the ground beneath, eliminating the need for stormwater drains, and preventing ponding.
Rainwater is therefore returned to the natural environment in the sub-grade (natural ground beneath), allowing soils to recharge.
Furthermore, permeable concrete provides opportunities for a larger building footprint, as this material doesn’t count as a ‘hard surface area’ (an area without natural ground i.e. grass, plants, rocks and soil).
Therefore, permeable concrete is a good option for property developers looking to maximise their available space.
How Permeable Concrete is Constructed
First, the surface level is made up of permeable concrete – which drains water through to the base course.
Second, the base course, is made up of stone aggregates (materials loosely compacted together), and comprises the structural foundation. Water then drains though to the sub-grade.
Third, the filter cloth (geotextile layer), is sometimes required depending on the soil type. It allows water to filter through, while preventing the sub-grade from clogging the base course.
Fourth, the sub-grade, is the undisturbed soil at the bottom. The strength of this influences how thick the base course needs to be.
Optional, is a sub-surface drain which directs excess water to the stormwater system.
