Garden drainage
South Manchester sits on a lot of clay, and clay does not let water through. When a garden stays wet for days after rain, the water has nowhere to go and nothing has been built to take it there.
Drainage is the service that saves people the most money, because standing water is what destroys paving, lawns and the ground against the house.
£800 – £1,500
What you are probably seeing
- A lawn that squelches for days after rain, or never really dries out
- Standing water on a patio that should be running off
- Water sitting against the house wall, or running towards the back door
- Moss taking over the grass, and bare muddy patches where it used to grow
- A gully or drain that overflows in heavy rain
- Water pouring off a shed or conservatory roof straight onto the ground
Why it happened
Usually falls. Ground and paving are built to shed water in a direction, and when the fall is flat, or runs the wrong way, water collects at the lowest point and stays there.
The rest is ground. Clay subsoil holds water, and a layer of compacted builders rubble under a lawn — common on any estate — makes it worse by sealing the surface.
How we do it
The method, start to finish.
- 01
We work out where the water is going
Levels taken, existing drainage traced, and the ground dug in a couple of places to see what we are dealing with. Guessing at drainage wastes your money.
- 02
Channel drains where water has to be caught
Across a patio, at a threshold or along the bottom of a slope — an ACO-type channel intercepts surface water before it reaches the house.
- 03
Land drains where ground has to be dried
Perforated pipe in a gravel trench, wrapped in membrane so it does not silt up, laid to a fall and run to an outfall. This is what fixes a waterlogged lawn.
- 04
Soakaways where there is nowhere else to go
A properly sized soakaway, dug to a depth that reaches ground that actually drains, and kept the required distance from the building.
- 05
Falls corrected
Sometimes the real answer is not a drain at all — it is relaying the paving to the right fall so the water leaves on its own.
Straight talk
What we will not do
We do not connect surface water into a foul drain. It is not permitted, it overloads the system and it comes back on you when the sewer surcharges. If there is no legal outfall we will say so and design a soakaway instead.
Questions we get asked
Why is my lawn waterlogged when my neighbour’s is fine?
Usually levels. If your garden is the low point, every neighbouring garden drains into it. The fix is to intercept that water before it arrives rather than fight it where it collects.
Can you fix drainage without digging the whole garden up?
Most of the time, yes. Land drains are narrow trenches and the turf goes back over them. It looks far more dramatic for a week than it does after a month.
Do I need permission for a soakaway?
For a domestic garden, normally not, but it has to be the right distance from the house and sized for the area it drains. We build to those rules whether anyone checks or not.
Will a drain fix water against my house wall?
Often, combined with lowering the ground level. Ground piled above the damp-proof course lets damp bridge into the wall, and no drain alone will solve that — see levelling and dig-outs.
Garden drainage in Wythenshawe, Northenden, Gatley, Heald Green, Cheadle, Timperley and Altrincham.
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