Drainage for sleeper retaining wall and adjacent Patio

[Painey]

Hi, hopefully some of you can help me here.

I'm currently in the process of removing an old patio and retaining wall at our house. The old wall forms one edge of the patio, furthest from the house and has been wrecked by water damage. it's only 2-3ft high and holds the lawn back and I want to replace it with one made from railway sleepers.

Where I'm a bit stuck is how to drain it. Usual procedure is a french drain and I'm fine with how these work. Problem being I've nowhere to direct the water from it. I can't let it go out onto next door's property and the only nearby drain it can go into is at the back corner of the house, some 5m away.

What I hope to do is run the drain, in some kind of pipe from behind the sleeper wall, perhaps underneath it, underneath the new patio and into where the guttering goes into. If I don't do this I literally can't see where it can go and I don't want to flood the new patio or next door.

So my questions are, can I run a pipe under the patio? It will all be properly compacted with a whacker plate. if yes should the pipe be solid or perforated (where it goes under the patio).

Thanks for your help - Chris

 

[foxhole]

Surely the lawn has drainage so should not require any in retaining wall.?

 

[theprinceofdarkness]

After re-reading your post ten times , I think that your lawn is actually at a higher level then the patio? In either case the unequal pressure on your wall will tend to push it over so it needs deep foundations. A railway sleeper laying on the soil will soon be joining you on the patio!
Frank

 

[r896neo]

Is the patio on the lower level? if so where does the water landing on the patio drain to?

You are right to consider the drainage behind the retaining wall, it is essential. The volume of water coming out of it however will be quite low, especially as the higher level is a lawn.

Leaving weep holes which simply discharge onto the patio should be fine and then let the small extra volume of water go wherever the patio drains to.

 

[mcluma]

After re-reading your post ten times , I think that your lawn is actually at a higher level then the patio? In either case the unequal pressure on your wall will tend to push it over so it needs deep foundations. A railway sleeper laying on the soil will soon be joining you on the patio!
Frank

NOT TRUE if....

Use proper steel reinforcement I-beams and place the railway sleepers in-between, good for centuries to come, that is if you use pressure treated railway sleepers

DSC_2466 by Chris, on Flickr

DSC_2467 by Chris, on Flickr

DSC_2492 by Chris, on Flickr

Untitled by Chris, on Flickr

 

[theprinceofdarkness]

Nice job mcluma, how many decades has it been in for? I built a 9" single skin wall on 6" x 6" foundation holding back 9" of soil, over 25 years the wall went out of plumb by about 3/4"!
Frank

 

[mcluma]

This is in

Nice job mcluma, how many decades has it been in for? I built a 9" single skin wall on 6" x 6" foundation holding back 9" of soil, over 25 years the wall went out of plumb by about 3/4"!
Frank

This is in now 5 years, I-joists are set 2 foot in the ground in concrete, this is not going anywhere soon