The Brew Cabin

Posted: **Fri Mar 01, 2013 10:10 am**

Iâ€™d be really grateful for advice on where to site and how to build a mini-soakaway for my back garden

I intend to dig a pit about 0.7m x 0.7m to a depth of 0.8m. Iâ€™ll line this pit with terram geo-textile fabric and fill the pit up to the top with aggregate of some sort. There is no need to connect a drainage pipe to this soakaway because storm water from the rest of my garden (and from all my neighboursâ€™ gardens) flows to this part of my ground naturally anyway, due to its low level and simple gravity. But the edge of the pit will be situated only 1 metre from the side wall of a garage. I do not wish to undermine the garage foundations.
Will a small soakaway of this size (0.7m x 0.7m x 0.8m) and construction at 1 metre distance pose any problems for the garage foundations?

Also, what would be the best type of aggregate to fill the pit with â€“ 10mm gravel, 20 mm gravel, 40 mm gravel, builders rubble or a mixture of all these materials?

Note my back garden slopes gently downhill away from the house, and huge puddles of water collect on the surface at the rear after heavy rainfall during October to January. The rear of my garden is also 1 foot lower than all my surrounding neighbours so their storm water runs off into my ground as well. Iâ€™m afraid conventional drainage isnâ€™t an option.

Thanks

JS

Posted: **Fri Mar 01, 2013 10:48 am**

No no no no,

There is a page on the main site specifically about soaks ways.

http://www.pavingexpert.com/drain08.html

First off do a permeability test otherwise you are building a storm water attenuation cell that will just hold back the water and still need to be connected to a drain.

Once the permeability test has been conducted then you can progress to building your soakaway 5 metres (if possible) away from your house.

Re undermining your garage without seeing it or knowing what footing it is we'd be guessing but you don't want to be that close anyway.

Second don't fill it with aggregate get a couple of the specialist crates from a builders merchant they create such a better job and won't plug up like an aggregate filled one might.

Plus there volume is massive compared to a aggregate filled one, right I'm on my phone so kinda lost if that was all the points ...

Edited By GB_Groundworks on 1362135118

Posted: **Fri Mar 01, 2013 2:06 pm**

I suspect you will be on heavy clay, a soakaway will still make a difference but it will be minor. I tried it at my place 2m square, filled with hardcore at the lowest point and while it does fill up fast and empty slow it only holds a small amount really as once its full it drops maybe an inch a day in dry weather. After maybe 3 days of rain im still flooded out.

Ideally you need some perforated ground drainage leading to some kind of outlet, being on clay a soakaway isnt the option here... And i would never suggest you run it to the main drains... Honest.

The Brew Cabin

Mini-soakaway - Distance from garage wall