Sustainable drainage solutions

Since the 2008 legislation put in place by the government, in an effort to reduce flash flooding in urban areas, all hard landscaping covering front gardens and driveways larger than 5M2 must include a 'sustainable urban drainage system'.

In other words you can't install a new surface to your driveway or front garden and simply drain the surface water onto the public highway.

What does this mean for your project?

It means that you are responsible for managing your own surface water run off, which sounds like it could be complicated, but there are some clever landscaping products available to help make it simple.

Firstly, 'permeable paving'. This is a system whereby surface water is allowed to drain down through specially designed gaps in the surface, through a free draining sub-base, and into the ground.

Secondly, 'soak-away modules'. These are extremely strong yet 95% empty crates, or 'cells' which, unlike the old fashioned hole full of rubble idea of a soak-away, can cater for large quantities of water, holding it in an underground cavity until it soaks away into the ground.

An example of a sustainable drainage system from our portfolio:

Our brief for this project was to resurface this ex-farmyard driveway and deal with the surface water issue in a sustainable manner, whilst taking into account that the property and outbuildings were grade 2 listed and of local historical interest.

April showers

The first job was to remove the existing surfacing for recycling, and excavate the main body of the driveway and parking areas to a depth of 250mm (10" in old money).

Big boys toys

All excavated material was collected and recycled by a local quarry.

First scrape of the area.

Once the area was down to depth and the excavated material had been removed, we then back-filled with recycled crushed concrete.

First 20 tonne delivery

Using the excavator this and two more deliveries of crushed concrete were spread and leveled across the site.

This sub-base layer was then compacted using a vibrating plate to form a hard but free draining foundation.

The next layer of this driveway surface was a sand screed of approximately 50mm (2").

The whole area was leveled and compacted in layers to form a laying base for the free draining surface.

With the assistance of this cat the surface Geo-grid was laid onto the compacted sand screed. The grid is supplied in individual cells which lock together to form an extremely strong surface.

Once the whole area was covered with the Geo-grid the final layer was 20mm crushed shingle. The shingle fills the individual pockets of the grid, making it capable of bearing several tonnes per M2, and allowing surface water to drain freely.

This surface had to be strong enough to cope with large vehicles, this area was the route the customers heating oil delivery lorry took when delivering. 

Here is the finished article, a large but sustainably drained driveway and parking area, in keeping with the property, with no more puddles!