This soakaway will need an overflow at the far end

[malakoffee]

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• malakoffee
• 24 Jan 2013
• 1

This is my - completely full - soakway test trench. Most of the pipework is already in place, but I haven't buried the crates yet.

2012 has been a rather demanding year for handling/removing rainwater from the roof.
I have seen the water table in the back garden rise to the surface of the lawn twice - i.e. completely overwhelmed!

Untitled

• malakoffee
• 24 Jan 2013
• 1

At the far end of the trench the water overflows and runs away into other gardens. Apparently, this surface water overflow has occurred previously, in extreme circumstances, before I dug my test trench. . . . so I don't feel quite so bad about it.

This new soakaway replaces a badly-placed, clogged and inadequate old soakaway on the high side of the house.

Also, the neighbour's house was feeding into that old soakaway, via a porous pipe, running across the front of my house about 1.5 metres from the front wall.

My ( recently-acquired ) house had severe penetrating damp on three sides before I dug out the clay against the walls, installed french-drains and reorganised the rainwater drainage.

Despite a very wet year the house is is much dryer inside.

It is a pity that the new soakaway in the back garden doesn't work as hoped and will need a surface overflow.

 

[JohnD]

Did you post this for our information, or do you have a question needing a response?

 

[Mursal]

Go deeper and take out the grass, back fill with rock/stone, cover with plastic and 75mm of topsoil, shake on grass seed. Bur I'm sure you will get better and more experienced advice from other members

 

[freddiemercurystwin]

Soakaway's don't generally work in clay. Where will your overflow drain then?

 

[malakoffee]

Soakaway's don't generally work in clay. Where will your overflow drain then?

Local Building Control classify this area as "sandy clay".

Many houses in this location have been built ( in the 1930s ) with rainwater soakaways only, fed by porous pipes - although the topography and ground conditions may vary from house to house.

In this case, with the extraordinary rainfall in 2012, the old ( shared ) soakaway and pipes could only supersaturate the surrounding soil and eventually raise the water table to the surface, where it would run-off at the bottom of the garden.

Go deeper and take out the grass, back fill with rock/stone, cover with plastic and 75mm of topsoil, shake on grass seed.

In this case the deeper I dig the crates the sooner the water table will rise and fill them completely.

Did you post this for our information, or do you have a question needing a response?

Sorry about the mixed message here. This topic started off in DIY disasters as a warning to all.
What do I really want to know ?? . . . . I still have an alternative option of breaking into a shared sewer and abandoning the soakway. I suspect that this will be fiercely resisted through official channels.
How best to approach this ??

PS. When purchasing the house the search documents recorded the house as having combined drainage ( although it was all [failed] soakaways ).
The water charges are for combined drainage.
i.e. The official world thinks that the house already has combined drainage.

Thanks

 

[Mursal]

Well you better put reality inline with official documents. Just do it at night (we find a party is a good distraction if you have to make noise) and be careful if a contractor gets involved.