I want to help the drainage of rainwater away from the house. I've dug a trench which drains OK, next is to put in a plastic pipe and cover it with pea gravel. Is the idea of a french drain to drill holes in the plastic pipe so that water seeps in? Seems to me there shouldnt be holes in the bottom of the pipe so any mud wont stay at the bottom but will get swept down the pipe..
is this so? any other advice please?
[george]
I don't know if it's available here, but in France they sell a standard sized plastic pipe with numerous sawn slots already in it for this purpose. Unfortunately I can't help with any info on how it is installed.
SteveW
In article , george (dicegeorge) scribeth thus
You can IIRC .. get Osma drain that already has these apertures, rectangular slots already in it.
Just for that sort of application....
Same stuff sold in Italy in 50 metre coils.
The technigue is to lay a trench and level with pea shingle/sharp sand. Line the trench with geotextile long enough to wrap over the top of the drain. Lay the drain. wrap over the fabric and weight it down with coarse gravel. Continue with various sized rocks if available. If it's desired to finish it off with gravel I put down a blanket of geotextile then lay the gravel on that.
The drain iself needs to be led to a soakway or in my case a sand trap then a 40 tonne tank then a soakaway.
Toom
Yes there should be holes in the bottom. Look up "Paving Expert".
If the area is traffic'd you need rigid clay pipe (perforated land drain). Otherwise use plastic pipe which comes in 60mm 80mm & up sizes.
Someone on Ebay does 25m lengths cheap if your local Jewsons etc doesn't.
To install it you dig a trench, line it with geotextile, infill with various sized washed gravel down to pea gravel around the pipe. Pipe is laid with a slight gradient either to soakaway or very low level sunken grid (common on some houses, but not ideal as you would need to cover the open end with mesh to stop things hiding in it) or into a P- trap properly fitted (conventional, better).
land drain - try agricultural supply places (sell fencing, field gates, farmer's metalwork supplies, feed (for more than a few dogs) - you get the idea)
various diameters available - 4" or 6" common -
nb the ones I've got have slots all around but in practice trying to keep ALL the water in the pipe is unnecessary as you can't ensure that all the water that enters the land drain will actually go through the slits into the pipe in the first place
Idea is that there's an "escape route" for water to go once the ground under the pipe is saturated - ground above and around it is still drier than it was before
cheers jim
Steve Firth coughed up some electrons that declared:
Seen that pipe in either B&Q or Wickes recently
available here.
Simply shingle it in place.
The one I've seen in france is rigid, 3 or 4m lengths of around 125mm diameter. I didn't know you could get it in coils, handy if I ever need some.
SteveW
my french drains will only be about 4 yards long, just to get water away from the house..
im th> >
The message from Steve Walker contains these words:
The stuff I have used was 4" and came in a 25 metre coil IIRC. It was quite cheap. The ballast to fill round it cost more than the pipe. Should be available at any builders merchant. I tried to get some 3" for a French drain but that would have been a special order of 50 metres.
It should be available in larger diameters as well but I don't know how easy that would be to get.
A neighbour had some remedial work done on a septic tank drainage field some years ago. The contractor insisted on using rigid brown plastic 4" piping and drilling his own holes. ISTR it took him quite some time to drill the holes.
Thanks for all the advice and the weblinks, I understand a lot more about it now the difference between a land drain and a soakaway... and unless I get any new ideas I'm going to make a temporary one tomorrow which should last a few years with some drainpipe and slots on top using a uk-diy screwdriver (a.k.a anglegrinder) [g]
Dave Osborne wrote:
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "george (dicegeorge)" saying something like:
Proper drainage pipe has many more slots than you could arsed putting in with an anglegrinder and it's cheap as chips. You'll find it in builders yards and farm stores.
almost the depth of the diameter of your pipe (as it were ;>)) before ANY drainage will take place from your gravel/trench/damp area using the pipe...
still recommend you buy some "many slotted" land drain - where are you? I have 1/2 a 4" roll kicking about somewhere
cheers jim
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