Jamie Gledhill, Technical Engineer at Brett Landscaping, advises on the key requirements and considerations, when using permeable block paving.
Last year Prime Minister Rishi Sunak raised eyebrows when he declared an end to the ‘war on motorists’, focusing on traffic-calming schemes and the government’s pledge to ban the sale of new petrol and diesel cars by 2035. If there is a war on motorists, I would argue that it is a battle over territory.
According to research from car manufacturer Vauxhall, 40% of motorists don’t have access to a driveway, which rises to 60% of motorists who live in our towns. The clean transport campaign group Transport & Environment has revealed that new car models are getting too big for British roads, exceeding the 180cm minimum for on-street parking.
It is no wonder that research by Aviva Home Insurance in summer 2022 found that as many as 25% of homeowners have already made changes to their outside space to accommodate vehicles with a further 17% of homeowners planning to increase their driveway areas.
This motorist demand for space needs to find a working balance with the homeowner responsibility to minimise the risk and impact on roadside drains, sewers and to neighbouring land/property from rainwater run-off on their property. This is an issue builders need to flag with their customers before work starts.
It is vital to note that since 2008, any installation of a driveway using an impermeable surface material that doesn’t actively absorb rainwater and is more than five square metres in area size, will require planning permission from a local planning authority.
For a sense of scale, the standard UK car park bay size of 2.5 metres by 5 metres generates an area of 12.5 square metres, so it is a very low threshold before planning permission is a requirement when using impermeable driveway materials such as asphalt, porcelain paving slabs or tarmac.
These regulations were introduced to account for the huge rise in properties where garden land was being converted to additional parking spaces for cars, leading to ‘urban creep’. This has reduced the available area for rainwater to be absorbed naturally back into the ground, leading to more surface water runoff reaching roadside drains and sewer systems which were never intended to take this additional surface water.
The solution to a balance between usable area for traffic, effective stormwater management and meeting legal requirements is available and in use. Planning permission is rarely required if using concrete block permeable paving as long as it is installed with a fully permeable sub-base.
These systems, such as Brett Landscaping’s Invicta Flow and Omega Flow, and others like them, offer great design flexibility to meet homeowner need for space while absorbing and managing rainwater.
Builders and driveway specialists do have other incentives for advising the use of permeable block paving. The material is readily available in a wide range of product options and remains at a competitive cost per square metre comparable to permeable tarmac.
Permeable block paving can be installed in wet weather, which allows work to continue, even during the unpredictable UK downpours. If the paving is installed properly the ongoing maintenance requirements and costs for the homeowner is minimal, while homeowners may also have a financial incentive, as some water companies will offer money off water bills if the water landing on a property is disconnected from the local sewer system.
All the above sets out the current requirements and practicalities of a driveway conversion or extension. Brett Landscaping works closely with the Association of SuDS Authorities (ASA), which represents local authorities across England with supporting the delivery of sustainable drainage.
Co-Chair of the ASA, and head of the Flood Risk Management Team at Lancashire County Council, Laura Bigley, argues that with increasing storm events placing existing drainage systems under growing pressure, homeowners have an intrinsic social responsibility to think about how their renovations will affect the properties in their vicinity:
“Land drainage law is a complex area of regulations, but at its centre is a very simple premise – the landowner is responsible for drainage on their land and should not cause a nuisance to others. While homeowners should not alter their terrain without understanding how this will affect other properties, there is still a situation where building work proceeds without due diligence by the property owner.”
“We hope that in time permeable surfaces will become ‘the norm’ for homeowners to use on their driveways and garden areas. This will help us all contribute towards responsibly managing surface water from our property by keeping it out of the drainage systems and mimicking natural processes.”
The ASA advises that there are some measures that can be taken to compensate for the lost permeable area and habitat an extended driveway may cause. This provides an opportunity for builders to offer further advice on how to create a flood and drought resilient garden.
The planting of evergreen hedges along the boundaries of land in preference to fencing assists with surface water management and absorption, but also provides noise reduction an improvement in air quality and habitat for wildlife.
The installation of water butts is another great option for homeowners to consider. They are cheap, easy to install and can capture many litres of rainwater, helping to better manage flood risk in the community. There are many sizes, styles and even ‘smart’ water butts to choose from to suit any project.
Advising customers of permeable driveway options to avoid the need for planning permission, and that ‘urban creep’ can be offset with green solutions does not have to be a bruising battle, but instead can lead to a driveway that is both practical, cost effective and socially responsible.
For further information on permeable paving from Brett Landscaping visit https://www.brettlandscaping.co.uk/
