As housebuilders and developers face increasing pressure to manage surface water, deliver climate resilience and maximise land use, Sustainable Drainage Systems (SuDS) have become a central consideration. With more frequent extreme rainfall events, tightening planning requirements and growing concerns around flood risk, traditional drainage approaches are no longer sufficient.
For those seeking practical, compliant and cost-effective drainage solutions, concrete block permeable paving offers a highly effective way to manage water at source while delivering the durability and aesthetics expected of modern hard landscaping. A common misconception is that water passes directly through permeable paving blocks themselves. In reality the blocks are manufactured from durable concrete and remain impermeable. Permeable paving incorporates wider joints between individual blocks, which are filled with specially graded aggregate. Rainwater drains through these joints before entering the engineered pavement structure below.
At the heart of SuDS design is the principle of source control, managing rainfall close to where it lands rather than transferring the problem elsewhere within the drainage network. Concrete block permeable paving achieves this by capturing and temporarily storing rainwater within the pavement structure. Beneath the surface sits a sub-base formed from open-graded aggregate containing significant void space. This creates an underground reservoir that can retain stormwater before releasing it in a controlled manner.
On sites where infiltration is unsuitable due to ground conditions or groundwater levels, the system can be connected to other SuDS features, including swales, detention basins or controlled discharge systems.This flexibility makes permeable paving suitable across a wide range of residential and mixed-use developments.
REDUCING RELIANCE ON TRADITIONAL DRAINAGE
A significant benefit of permeable paving is its ability to reduce dependence on conventional drainage infrastructure. Traditional drainage systems often rely on networks of gullies, pipes, chambers and attenuation tanks, all of which require space, installation costs and long-term maintenance. By contrast, permeable paving integrates drainage and attenuation directly within the pavement.
The system can intercept and absorb the first 5mm of a rainfall event, helping to reduce runoff volumes and pressure on local drainage networks. Roads, parking areas, driveways and public realm spaces effectively become part of the site’s drainage strategy, providing distributed storage across the development rather than concentrating water in dedicated drainage assets. This can help optimise land use and potentially increase developable area while still meeting planning and SuDS requirements.
WATER QUALITY BENEFITS
Modern drainage design must also address the quaity of runoff. Surface water from roads, parking areas and driveways can contain pollutants such as hydrocarbons, tyre wear particles, sediments, heavy metals and microplastics. Without treatment, these contaminants can enter watercourses and damage local ecosystems.
Permeable paving provides an effective first stage of water treatment. As water passes through the joints and aggregate layers, pollutants are trapped within the pavement structure. Naturally occurring microorganisms within the sub-base can break down hydrocarbons and other contaminants over time. This means permeable paving can provide two stages of treatment before runoff enters the wider drainage system, supporting better environmental outcomes while helping satisfy SuDS requirements. www.brettlandscaping.co.uk