My own soakaway design

[marsaday]

What do you all think about my soak away design for my drive and my new shed in the garden (2 separate soakaways).

I have looked at the suds cages and these seem fine, but i am inclined to go for a lined pit with a top so i can service it in the future if any issues.

However my design is a bit different. I propose to use 2 plastic 320mm risers with a plastic lid on the top. I would drill a hole into the side to take a 100mm land drain which would be connected to the drainage channel on the drive and a gully on the shed.

Would i need to drill more holes into the plastic risers or can i leave as is?

We are on very sandy soil and so drainage is good.

[seanandruby]

330ml doesn't seem very deep as you should be calculating for surcharging. I'd definetly run the pipework to gullies, silt trap first otherwise it will silt up over time. read soakaway pages

[marsaday]

The depth will be 640mm (2 risers).

This is at the bottom of a 30m garden so no drainage down there.

The drive is a different matter, but i don't think i can connect up to my sewer outlet as the whole point of drive drainage is to direct the water onto the garden and let it go away naturally.

[Tony McC]

Even 640mm isn't all that deep for a soakaway.

At 450mm diameter, that gives a volume of only 0.1m³ - how big an area os being drained into that? Even at 600mm dia, the volume only becomes 0.18m³, whereas with a single crate we look at volumes of around 0.25m³. For areas of over about 80m², we'd probably use a double-crate soakaway.

[marsaday]

Sorry for late reply.

The roof area is 34sqm.

At the moment the hole seems to be doing well. We are on a very sandy soil so all the area and gardens are well drained.

[Tony McC]

You will be making many people green with envy - oh, for a sandy soil when it comes to drainage!