Land drain under path? - ...is this wise

[seanandruby]

If only drainage was that simple ??? Your trying to drain a garden by digging out 50ml. You already stated there isn't any stone or terran around the existing filter drain. " from what i've been told", you say: I am trying to help m8 but you don't seem to want to do the right thing, " it is solid clay" how the feck is a 50 ml. overlay of chippings gonna solve your problem ???

[seanandruby]

Sorry m8. You would be better suited putting the drain trench at the sides of your path down 200/300 and camber your path for surface water to run off. Use geo-membrane not weed barrier.

Sean, do we really need a camber on a path thats probably no more than a metre wide?

In short...yes. it is either a path, or a drainage trench, in my mind it can't be both. The guy asked for opinions, you have yours i have mine. At 50 ml on hard clay it will just fill up with surface water and the garden will still be waterlogged.it needs to drain to a drainage trench. If not a camber then it still needs a crossfall or the water will lay there on clay soil.

[losttheplot]

I created a picture but now find that I am unable to upload pictures to this forum!

I feel like I'm talking a different language so let me reiterate what I said previously as simply as I can. My garden has an existing perforated land drain running across the bottom (left to right) at about 1m deep. It has no gravel around it, so it will not be working as intended, however, it is clear of silt and acting as a pipe leading directly to a roadside drain - I tested it by sticking a hose in the side and watched the water come out the other end. In other words, if I join a new pipe or land drain to it, I can use it to take water away from my garden. This was never in doubt and I did not ask about this.

We intend to lay a proper land-drain with 100mm perforated pipe in a 600mm trench surrounded by gravel and enclosed in a geo-membrane. This will run from the patio down to the existing pipe (land-drain) mentioned above. We have read the articles on this website and are clear about what is needed. We intend to join the new land-drain into the old land-drain in order to use it as an outflow from our new land-drain. We will use a proper union/junction which we will cut down to suit the pipe sizes. This was never in doubt and I did not ask about this.

We intend to lay a slate-chippings path running down the length of our garden, in order that we can use it to walk on. The course of this path is next to the high-ground of our neighbour, so it runs through what is currently often waterlogged lawn. This was never in doubt and I did not ask about this.

Here goes with the question again: is there any reason why we should not run the new land-drain (in its 600mm trench, joining into the existing pipe that will take away the water) directly under what will end up as a simple slate-chippings path?

I know you are trying to help, Sean, and I really appreciate it, but I feel like you are answering someone else's post, and I don't know how much clearer I can be!

[seanandruby]

Yes i understand ltp. Now you try to understand something, i try to answer your question by saying what i would do. If you want to dig a trench an fill it that deep with stone etc; and still use it as a footpath then do it m8. You said "it's just a case of digging out the turf and CHUCKING in 2ins of slate." " ( bodge and fail ) Now you are saying "600 deep" :O What i am trying to tell you is that a footpath needs a certain make up of subase, bedding layer etc: you are doing away with those so therefore it is not a footpath but a drainage trench/soakaway, which is i think what you want? Footpaths like anything else needs to be drained properly.

[lemoncurd1702]

http://www.pavingexpert.com/permabl1.htm

Construct your path as in the above link using your slate as the surface rather than block paving.

[losttheplot]

Thanks for the link Ganger, which kinda answers my question in principle. I intended to lay a semi-permiable/porous/whatever path, so that rain water would flow downwards through the slate and membrane, into the land-drain trench, and that is exactly what is shown in that link, albeit far less crudely than my plan. I have also managed to find some council plans on the web, that show paths through parks with land-drains directly underneath, so this also shows that the principle is sound.

The important thing to note, and one that Sean has now highlighted (sorry Sean, I appreciate you're trying hard to help, but you have gone off on so many tangents and misunderstandings that my original question seems to have been missed) is that my path needs to have a good sub-base (cambered or otherwise). I can also take from the other link that as long as that sub-base allows water to pass through it, I should be okay locating it directly overhead the land-drain trench.

I think we've got there in the end ...yes?

[seanandruby]

You mean your agreeing that a sub base needs to be used ??? flipping hallelujah :;):

[losttheplot]

You mean your agreeing that a sub base needs to be used ??? flipping hallelujah :;):

Yes Sean - this is why I posted my question: to find out what I needed to know, despite having had to go round the houses to get there. But I still have not found any reason why I should not position the drain under the path.

Thanks for all contributions of help

[seanandruby]

No reason why. I was only trying to say that a drainage trench is not a path. Drainage as in a permeable drive etc; is ok as long as the water is draining. A path that is just a path would benefit from being constructed right especially with clay as s sub soil. And it would need to be drained. It is normal working practice to create a fall to a siutable channel. But please don't think that 60 ml of slate chucked on top of weed membraje constitutes a good drainage channel. Wires may have been crossed and if so i apologise for that. Hope your project works out for you.