Drainage solutions for Front Gardens
The hardscaping of many front gardens over recent years have led to localised flooding and pollution issues. The SUDS (Sustainable Urban Drainage Systems) legislation of 2008 seeks to help tackle these issues by encourage surface rainfall to be managed as close as possible to where it falls. This is mainly encouraged three ways:
Rainfall soaking into the ground via a permeable surface
Transport of surface water to a storage unit e.g a soakaway where it is released into the ground slowly
Transpired through vegetation (green roofs, rain gardens)
I've investigated the pros and cons of various solutions for a permeable or SUDS compliant front garden. Here's my thoughts.
Permeable paving - There are lots of permeable paving products on the market, most of them made of concrete, but in my view there are only a few which have the aesthetic appeal of natural stone. Bradstone Woburn Rumbled Infilta is fully permeable when laid on the correct laying course of 50mm course grade aggregate (CGA) 2-6mm(with no fines) and a sub base of 250mm CGA 4-20mm with geotextile between the laying course and sub base and sub base and ground. The jointing should also be wider at 6mm and made of 1-4mm clean hard crushed stone.
I personally prefer the look of clay pavers which are permeable providing they are laid on the correct subbase, as per the concrete pavers above. Chelmer Valley have a huge range of pavers from traditional to more contemporary looking designs but is a more expensive option than concrete pavers.
2. Gravel - This is a very versatile material, with uses for paths, driveways and can even be planted into, for a softer look. For low traffic area I tend to use 14-20mm Flint Gravel from CED stone as the range of colours in this gravel combine well with almost all other materials. The 14mm size can also be used with Cedapath or Cedadrive stabilisation systems.
3. Resin bound gravel - This surface made of natural aggregates bound with a water permeable resin which makes it a fully SUDS compliant surface, providing it is laid on the correct sub base of inert aggregate 4-20mm retained with a cellular matrix system on top of a geotextile membrane. Sureset offer a wide range of natural aggregate colours, with the benefits of no loose stones and easy maintenance.
4. Grass Block Pavers - These are concrete paving blocks with gaps to allow grass, resilient plants or aggregate between them. The concrete blocks mean they are robust enough to park a car on but the grass, or other plants soften the look. Most of the pavers available have a uniform pattern which I don't think look as good but I've found these Swiss designed LUNIX pavers which have a lovely randomised organic shape which look great with grass or aggregate or a mix of the two.
5. SUD compliant surface - Any surface can be used in a front garden but in order to be compliant the surface water has to be directed to a SUDS installation, such as a soakaway, flower bed or french drain within the garden and not directed into the underground drainage or sewage system. In a front garden a soakaway may not be practical as it needs to be at least 5m from the house and may not work well on clay soils. Directing rainfall into the flower beds or a French drain may be a more practical solution although probable water volumes will need to be calculated to ensure that these system are not overloaded. Trying to keep as large flower beds as possible within your front garden not only helps with this but will ensure your front gardens have a softer, more natural look.
It's really important for our environment that we embrace these options when redesigning our front gardens. I hope that this article offer enough information for you to make an informed choice.