Land drain

[Injured]

Been to look at a job over the weekend and the site is clay and has a high water table.
The client has dug throught the clay and found waterlogged sand.

the client needs land drain putting in to try to dry out the garden and keep the water away from the house which had/has standing water under the floor joists.

Obviously a land drain to a soakaway wouldnt work but was wondering if it could be piped into the existing combined drainage system or if anyone knows of another way.

The site is sloping towards the house quite steeply and the drain is running diagonally across the garden.

Any ideas/help??

Thanks

[Tony McC]

The only solution would be to drain to an existing SW outlet or to see if the clay layer can be penetrated by a sand drain.

[Injured]

Whats a sand drain??
Sorry to appear thick

[Dave_L]

A sand drain is basically a deep thin hole filled with sand and/or gravel that allows the water to percolate to to lower levels and more permeable layers of the sub-strata.

[Injured]

thanks I am now a little bit wiser :p :laugh:

[Tony McC]

Dave's spot on with his definition.

On the right sort of job, we'd auger a borehole through the clay/impermeable capping, drop in a rigid pipe vertically (clayware because plastic would deform) and fill it with clean gravel or coarse sand. There are parts of the world (such as Hindley Green near Wiggin) where the clay might be just 3-5m thick and it can be 'pierced' by creating sand drains to allow proper drainage of waterlogged site.

[Injured]

So would you put a few of these in or just one with land drain running to it??

Sounds like I need to investigate a bit more.

Thanks

[Mikey_C]

I would have thought one at the bottom of a soakaway/attenuation cell type affair, but this is only a WAG from a diy'er

[Dave_L]

So would you put a few of these in or just one with land drain running to it??

Sounds like I need to investigate a bit more.

All depends upon the expected flow into said drain.......