ACO Drainage, Channel Drainage or Linear Drainage is a method of draining surface water from hard surfaces such as tarmac or paving, using a long narrow drain covered by a grating which drains water along its entire length. You will have seen these long galvanised steel gratings in public areas such as car parks or shopping precincts, however channel drainage is also used for domestic applications such as drainage from driveways and patios.
Why do I need an ACO drain?
The SUDS legislation (Sustainable Urban Drainage Systems) and the subsequent Front Garden Rules were introduced in 2008 to combat the increase in urban flooding caused by an increased density of housing and other developments.
This urban development, and also the trend for paving or tarmacking front gardens, has led to an increase in impermeable paved areas. Rainwater is channelled into the overwhelmed storm drain system rather than naturally draining into the ground, and flooding occurs.
Hence, the installation of any new driveway with an impermeable surface (i.e. anything apart from gravel or a specialised permeable driveway block) that does not naturally drain into adjoining flower beds or lawn areas must now have its own self-contained drainage system.
Water cannot drain into the road, and the system must not drain into the storm drain, but rather into a soakaway.
These regulations do not apply to drainage to the rear of your property (such as a patio), however if your house is on a corner then they do apply to the side facing the road or path.
What is ACO Drainage?
ACO is actually the brand name of the leading global manufacturer of drainage solutions, and the ACO name has now become synonymous with this type of drain (think of it as the Hoover of channel drains). All of the channel drainage products offered at AVS are manufactured by ACO, including ACO RainDrain (polymer concrete), ACO HexDrain (polypropylene) and ACO HexDrain Brickslot.
Channel drainage relies on gravity to remove surface water, hence it is always positioned at the bottom of a shallow incline. In a domestic setting this might be at the entrance to your driveway or the threshold of your garage door (depending on which way the ground slopes), or at the edge of or within a paved area such as a patio. The drain itself is buried at a slight incline so that the water runs off into an adjacent soakaway or storm drain.
Channel drainage products are all given a Load Class which refers to the weight they can withstand in use. Domestic ACO drainage products have a Load Class of A15, meaning that they can withstand a load of 1.5 tonnes and are suitable for a domestic driveway drain.
What is a soakaway?
A soakaway is an underground structure that lets water from a drain gradually percolate into the surrounding ground, avoiding the build up of surface water. There are two main methods of constructing a soakaway - with ready made soakaway crates or with coarse ballast or rubble.
Soakaway crates are large plastic crates, formed from a fine grid network that holds incoming drainage water, allowing it to slowly soak into the surrounding ground. By wrapping the crate in a layer of permeable membrane the surrounding soil will not wash into the crate and block the drainage.
A ballast or rubble soakaway is essentially a pit, lined with permeable membrane and filled with aggregate. However, this is now seen as a less efficient method as the rubble does not allow as much water to be contained within the soakaway.
How to install an ACO drain
Installing channel drainage is very straightforward, especially at the edge of a paved area or within a block paved driveway.
- Dig a channel to accommodate the drain and a minimum 50mm bed of concrete
- Mark a line with taut string 3mm below the finished surface
- Lay the concrete base and level with enough clearance for the channel
- Vertically slot together the 1m channel lengths, using a hacksaw to adjust the overall length if necessary
- Fit end caps or an outlet end cap to connect the channel to a standard 110mm drainage pipe
- Lay the drainage channel on the bed of concrete, checking that there is a slight slope towards your drainage outlet
- Refill the channel and replace any surrounding paving
- Fit the grating - this should be 3mm below the level of the surrounding paving
What is slot drainage?
An ACO slot drain is a type of channel drain, but rather than having a full width grate has an offset, slot-like grate that drains into a full size channel. Slot drains are particularly useful when installing discrete drainage, such as within paved areas or flush with a wall.
Ask the experts
For further advice about your building project don’t hesitate to speak to our friendly and knowledgeable experts at your local AVS Fencing & Landscaping Supplies branch. Our ranges of ACO drainage components are available from stock subject to availability, click and collect from your local AVS Branch or home delivery within our AVS Branch delivery area.