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Posted: Fri Aug 14, 2015 7:07 pm
by mrpvs
Guys , can anyone advise me on this , I've got an area 20 sqm , dug down a good 6 inches into clay .
I've put a tanalised frame in and planning on backfilling with hardcore (mot) and a layer of sharp sand .
I've come home today and have a swimming pool!
Do you reckon the 6 inches of aggregate will give the rainwater a good chance of soaking through evenly ?
It normally takes a day or so to totally absorb the water , at the moment it's a low point so naturally fills when it rains , when I backfill it will be upto the level of flags .
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Posted: Sun Aug 16, 2015 8:16 am
by seanandruby
Are you planning on slabing it? Is there no where you can run a filter drain to?
Posted: Sun Aug 16, 2015 9:42 pm
by mrpvs
Hi , thanks for the reply , I'd given up hope on anyone answering to be honest , just spent the day digging out a french drain ,
I have run it diagonal from bottom left to top right in the pic , gonna dig out a bit of a soakway where the blue bags are , if it won't drain I'm gonna drop a tank and pump in , it's having hardcore and sharp sand tomorrow , then artificial grass .
Posted: Sun Aug 16, 2015 9:48 pm
by mrpvs
Few pics , hopefully it can give anyone else who comes across this thread an idea on how to deal with it .
I used - 67mm drainpipe , weed fabric , cable ties and a tonne of mixed 10 and 20 mm gravel .
Dug a downhill foot wide , 2 foot deep trench , covered the bottom with fabric and 2 inches of gravel , Drilled out 2 holes every foot on the pipe , wrapped the fabric around the pipe with a layer of gravel between the pipe and fabric (underside) secured with cable ties every 6 inches.
IMPORTANT - *holes must face downwards* also wrap the top end of the pipe with fabric to prevent any blockages .
Then backfilled the trench with gravel covering the top end(which is exposed in pics).
Then did a few run offs with the left over gravel - hopefully it works .
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Posted: Wed Aug 19, 2015 1:55 pm
by Tony McC
So: where is all that pipework draining to?
Posted: Wed Aug 19, 2015 5:22 pm
by mrpvs
I was gonna dig out and install a sump n pump , in honesty I was gonna fill the dug out with some 20 mm gravel and see how it copes for a week or so Prior to installing a sump .
The main problem I think is the area I dug out for the grass was just collecting all the water as it was the lowest point , I backfilled with 5 tonne of hardcore and a tonne and a half of sharp sand yesterday , nearly killed me .
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Posted: Thu Aug 20, 2015 9:48 am
by Tony McC
I don't think a gravel-filled hole will achieve anything other than wasting gravel.
The site floods, as we've seen. Digging a hole and filling it with gravel does nothing to aid drainage of the water unless the hole is deep enough to hit a permeable strata. A proper chamber or crate with a float-switch pump sending the water to a suitable outfall is your only viable option.
Posted: Thu Aug 20, 2015 4:57 pm
by mrpvs
That's exactly what I'm thinking of doing , bury a 200 ltr drum below the level of the drain outlet ,
perforate the drum in several places (sides and bottom) allowing the water to soak through to the inside , surround the drum with gravel (sides and bottom)
My reasoning on the gravel and perforations is to allow some of the water to drain away naturally , rather than having the pump kicking in constantly , so it will only kick in when needed ..
Anything else I need to consider (apart from the outlet)?
Cheers .