Building a soakaway

[dobbslc]

I've been quoted £3K to build a soakaway in me back garden! Sounds a lot to basically dig a hole!
So I'm looking at doing it for myself, any tips or tricks on doing it from you guys?
It'll be 1x1x1m wide and I'm thinking of using the plastic crates, I'll need 3 drains run into it from about 5 to 6m away.

 

[andyclimax]

what ground conditions . clay , loam , rock? if it is clay forget it, it will only work as a holding tank and drain away very very slowly. the plastic crates seam to get ok reviews but i have no experance of them . the best place to look is a website called the paving expert. it will tell you everything. £3k is a bit much but how good is access, where is the spoil to go , how good is digging, a 1m cube hole is a good size and if you are hand digging you will soon know about it .

 

[Fazerruss]

How much!!!!
Not a lot to it really. Dig a square hole, chuck the crate in run pipes to it I cover with visqueen before any agrigate to stop it filling with muck.
I did one last year for my in-laws driveway. The crates are very efficient even in clay as the 1m3 hole will hold nearly 1m3 of water.
Never had a problem since and the garage was always flooding even with a short rainfall on a roughly 10m2 area of block paving.
The soak away was dug in clay soil too.

 

[andyclimax]

http://www.pavingexpert.com

 

[Rig Pig]

I have recently put a 3m square one in, it took 2 of us a day with a mini digger and dump truck, backfilled with rubble.
Cost was around £300, I added the spoil to the heap from my foundations, a grab truck is the cheapest (lazy!) way to get shot of spoil.
Don't forget to put membrane on top and sides to stop it blocking with fine material.

 

[Shox Dr]

I put 2 concrete drainage rings 1.8mx 1.2m in the front garden to hold run off.

£175 Man with 3t digger and wagon to dig hole take away soil
£200 concrete rings and lids (seconds)
£130 concrete base.
£200 drainage pipe/fittings

Took me 2 days to plumb it up.

So 3k is takin the p

 

[brightspark]

as post 2 its ok putting a soakaway in but if its in clay ground its going nowhere and will just fill up. do some investigation before you start I . just put land drains round the daughters house using perforated pipe and gravel but managed to get them in to a clean water drain along with the other pipes I put in

 

[pressbrake1]

If it’s clay you create what’s called a deep bore soak away. Basically you have a tank with a bore hole going down to material like limestone or gravel.
I found this out due to being stupid enough to get building control involved. Bore hole ain’t cheap

 

[Pete.]

Water does travel through some types of clay. My current job is sinking shafts in sandy clay. Two of them I had to have a hydrainer pump running constantly to keep the water out.

 

[Bobtail4x4]

I always suggest using a builders one ton sack as a liner and another over the top to prevent the soakaway silting up.
the rule of thumb is a M3 per fallpipe locally.

dont fill it with gravel as people often do, you need lots of spaces for the liquid to sit in, brick rubble,crates or a built hollow soakaway are the best.

 

[KaneH]

Have you had the ground tested? Simple percolation test will tell you if you’re going to be ******* money away or not. No use installing a soakaway if you can’t drain to to ground as mentioned above.

 

[dobbslc]

If it’s clay you create what’s called a deep bore soak away. Basically you have a tank with a bore hole going down to material like limestone or gravel.
I found this out due to being stupid enough to get building control involved. Bore hole ain’t cheap

Building control are already involved due to the house extension....
We are on clay with some stones/gravel in it (south Hertfordshire so just on the edge of London clay and material the last glacier brought down)
He talked about putting 5 holes in the bottom and test with water to check the drainage.

 

[brightspark]

Water does travel through some types of clay. My current job is sinking shafts in sandy clay. Two of them I had to have a hydrainer pump running constantly to keep the water out.

I found out the hard way that clay is in layers dug out for a pit in the garage .got it all shuttered up for concreting and it started raining you could see the water coming through the seam and then the whole bloody issue caved in I put a pump in the bottom to no avail it still went

 

[Pete.]

Yep it does form in layers - that's why I'm sinking shafts. They did test holes that came back with soft clay, dry conditions which are easily machine-diggable with a grab from the surface. Only trouble was down near finished depth it turned to hard clay with a layer of mudstone underneath, and when you hit that the water came pouring in.

Shaft with clay in it. You can just see the water creeping in.

Next morning:

 

[brightspark]

the jcb driver I hired did warn me get it concreted as soon as possible but it rained the night before and the heavens opened up theres no wonder people get killed not properly shuttering holes up even 6 foot deep

 

[pressbrake1]

Yep it does form in layers - that's why I'm sinking shafts. They did test holes that came back with soft clay, dry conditions which are easily machine-diggable with a grab from the surface. Only trouble was down near finished depth it turned to hard clay with a layer of mudstone underneath, and when you hit that the water came pouring in.

Shaft with clay in it. You can just see the water creeping in.

View attachment 171370

Next morning:

View attachment 171371

What company does your test holes?

 

[Pete.]

What company does your test holes?

I don't know mate they were done for the client ages ago.

 

[8ob]

We had to deal with drainage on a job that was in clay, as there was little to no chance of a soakaway ever working we fitted a rainwater harvesting system. Might be worth a look as they are not that expensive and will save a few quid on garden water usage.

Bob



Just goes in on a bed of soft sand

 

[dobbslc]

All good info!
@andyclimax

http://www.pavingexpert.com

Good site that I've just spent an hour in the bath reading up!
We do already have an old 1950's soak away in the garden but its now to close to the house (5m min) and the clay pipe feeding it was full of crap and almost blocked. Despite that the lawn never was soggy so I assume it was working still and the ground is capable of taking the rainfall.
There has to be a patio area at the back of the house so I need to get the levels right to avoid the pipes being to high in the ground under the patio.

 

[gaz1]

use a french drain reference if you can

hole soil pipe and straight into sewer pipe cover over with pebles