How to add water drainage and make a gravel side path?

[Troy_]

Hi all,

After walking around a bunnings for 2 hours I realised I need some help to come up with a plan to gravel this path down the side of this brand new house I've just moved into. I don't know much about anything landscaping and home owning so I really appreiciate any advice and infomation sources you can link me to. I'm reseraching like mad but it's frustrating. Everyone has different ways of doing things and most information just boils down to "be careful" and/or "just get a professional". I can't afford a professional and I'm not convinced I need one.

It was going to be straightforward until we had a big downpour and then there was a swimming pool down here. About 3 inches of water just pooled all the way down here. It did drain away after the rain stopped. So it might actually be fine to just cut the pipe, whack a grate on it and start laying down sand/gravel.

But water would still pool up to the top of the drain pipe and a full inch of water down here while it rains can't be good for the slab? Maybe it doesn't matter while it rains, as long as it drains away?

I would've thought it would be agi pipe from the downpipe to the storm water drain just in front of the bin but it appears it's PVC pipe all the way. No pipe along the side of the patio, which did fill with water during the rain.

So what are my options?

I could put two shallow 3-4 meter trenches, one from halfway between the far drain and that downpipe and the other starting from the corner of the patio that slopes towards the downpipe in the photo. I'm not sure if that's a good idea, if it's even nessecary or if it is, how to connect agi pipe to that PVC pipe.

Alternatively - leave the far drain as is. I just do the one trench starting from the end of the patio the photo is taken from, sloping toward the downpipe, might solve a great deal of the problem. Looking at the photos, I might be making a bigger deal out of this than need be. I live alone so I wind myself up often.

I've pretty much convinced myself typing this out that if I just put down something that will guide the water towards that far pipe it would be enough. Probably?

Then the other important question is what to put under the gravel that would actually take the space from the water, lift it up and guide it away to the drain. This whole job would be a lot simpler if I knew of a way to just fill in the space (without concrete) so that the water can't pool below the drain level and slope it all towards the one drain. Instead of digging trenches and cutting PVC pipe.

I appreciate any help. I'm available for a chat if someone thinks it might be easier to give me a call.

[Jewelleryrescue]

Hi @Troy_

Yes thats alot of water really.  Must be coming in from next door run off possibly which you cant stop.

So the simplest way is to  dig a 200 deep 200 wide trench  To take a 100mm  agi pipe with slots .

  See the down pipes (storm water) the idea is to  tap into them with a  Y  junction for storm water pipe and add the buried  ag pipe  and join it  with a range of fitting from bunnings search bunnings for agi Pipe.

I would  tap into the storm water near the end of the house closest to camera on last photo and make  a second T join so the agi pipe  collects water from 2 directions  from besides the house and from  further into backyard too.

So dig 200 x 200mm put a layer of blue metal stones or other 20mm thick base then lay the pipe on top of  stones and  connect plumbing then fill with same blue metal so any water  goes down the  trench into pipe and away.

You could  use a 65mm agi pipe and or a agi  with a  material sock on it to stop dirt blocking it in years to come. 

Hope this makes  some sort of sense if  not please  ask questions.

Vinidex 65mm x 20m Draincoil With Filter Sock

I/N: 4770255

$76.87

[Troy_]

Hi Jewelleryrescue ,

Thanks for the reply.

I was starting to think I could get away with filling it in with soil or something so that once it does become water logged and starts to fill up it will run into the drain that's already there.

If you don't think I'll get away with that I'll reconsider the trench, at least for the bit next to the patio without any storm water pipe.

So it'd be a trench, with the agi pipe with sock on the bottom, fill it in with 20mm stones and then add the gravel for walking on top which all flows down to that exposed storm water pipe which I'll need to add a junction. Maybe an extra drain grate there would be wise as well. I'm already digging it out I may as well go overkill.

Thanks again for the response.

[Jewelleryrescue]

Hi @Troy_

You  might be able to get the water to flow towards that drain on the  surface. especially if you concrete down that side.  OR put the drain in and fill that side  with  rocks as long as  surface dirt has the water  running the way you want.

  Plus theres  ready  made plastic drains that may suit you cover them in weed mat to help  filter dirt if it is an issue. But you will still need to stop dirt going in clogging up your pipes and thats  what the stones  help to do,

Normally in a storm situation i would say it just happens as long as  it goes away which is  partly true for us both . I need to do some storm  managment too

But thats a lot of water you had and over time can  cause problems  and down that side does see much sun so theres a week drying time. . I C thats a  storm water pipe sticking up  Great. Saves  having to tap into an existing line which is a  pain. 

Sounds  like you have a plan already thats all that matters.

[MitchellMc]

Welcome to the Bunnings Workshop community @Troy_. It's great to have you join us, and many thanks for your question about drainage.

Your property is on the lower side of a retaining wall. Subsurface water will always flow into this area, and unless you want this to be an ongoing issue for years to come, I'd suggest you bite the bullet and install adequate drainage. This includes running a 100mm slotted socked agline the full side length and installing surface drains.

Here's a helpful guide: How to install garden drainage.

I like your thinking about having the ground slopping towards the drain, but I don't believe that is the best solution here.

Please let me know if you have any questions.

Mitchell
 

[Troy_]

Thanks Mitchell,

I've resigned to digging a pair of trenches in an L shape around the patio and attaching two snap on connectors into the downpipe drains. Note the DP indicators on photo.

I will check out the rock along the side today, I'm not sure I'm capable to breaking through all that rock and/or concrete. Maybe that's why it filled with water so quick. If it's not soil and it's all concrete bits and rock it won't absorb water.

Will update later.

I appreciate the responses guys really.

edit: Question - I keep seeing these socked agi pipes but I'm also seeing people put "burrito wrap" the whole trench with landscape fabric. Is there a better way? Is the full burrito wrap not needed? I could do it it's just I don't know.

[MitchellMc]

Hi @Troy_,

I'd keep it simple and just dig a 100mm wide trench, drop the 100m socked agline in it and backfill with gravel.

You could certainly create a burrito-wrapped French drain, but I feel that's more work.

Mitchell

[Troy_]

Hi Mitchell,

Progress update.

After digging a trench and fishing water out of the trench for 3 days because, of course, it rained. I bought a pump to pump it out, which worked but it filled back up with water from the retaining wall side pretty quick. I thought I would have more time before it was full again.

edit: the trench stops where it does because the next several meters is pure concrete chunks. Which isn't impossible to get through but I'd like to finish this project and get back to my life at some point. I can add another trench system on the other side of the concrete, surely it's no big deal.

I think I need to wait for the ground to dry out. No big deal.

However I've run into another problem. That pipe you are looking at goes to the road. So I would assume it would slope towards the road but if you look closely you'll notice the water line is slanted down the pipe the WRONG WAY.

Didn't need a level to figure that out but here it is:

I could fill in a portion of this trench and make it way shorter, connect it to the top of the pipe because it likely isn't badly sloped enough that the water can't get out. Maybe half a pipe worth of water pools down this end and if the agi pipe pours in the top, it will still flow away. It seems like connecting a trench drain to a pipe sloping the wrong way will just back up the trench drain. It's pointless I would think.

OR my cranky and confused brain wants to fill in this side and ignore it. I could reverse the slope of the majority of the trench back towards the other downpipe, connect the whole thing down there and just call it a day. At least the portion around the alfresco won't flood and surely the extra drainage up this end will help water run out of the side of the house. I can put in another short trench drain down the other end of that side of the house.

I don't know if the builder's going to accept this as a defect and help me or what I could do or do I call a plumber now?

I better not make any decisions or doing anything right now. Maybe it's salvagable I just need some advice.

Thank you for your help,

Troy

[Troy_]

I really should have thought about this more and maybe contacted a structural engineer or something.

I'm reading advice stating I should never connect ag pipes to stormwater drains. Starting to think these trenches will just help water pool near the house.

Current thinking is I should fill in these trenches, fill in the low parts around the alfresco and the side of the house, add the grates and call it. This is a problem fundamental to these flat retained blocks. It comes off my neighbors yard (which isn't built yet, so once it is it should direct the water to the gutter somewhat) and gets stuck. It will sink into the soil slowly on that side and run off easily on the south side creating a wet side and a dry side.

Doesn't seem solvable by some dude with a shovel and an ag pipe. I'm in over my head here. I'm glad I found this out before I cut into my stormwater pipes.

[EricL]

Hi @Troy_ 

I'm sorry to hear about your pooling water issue at the side of your house. I'm wondering if this falls under the responsibility of the builder or the agency that sold this house to you. You would not have found about this issue unless you had heavy rain before purchasing the property. 

If your property is still under warranty, I suggest giving the agency a call and informing them of what's happening.

However, if it is outside your warranty period, I suggest digging a temporary drain channel 100mm wide by 100mm deep with a fall going towards the front of your house past the bin. This is on the condition that there are no concrete barriers in the way. You only need to keep this channel until you've arranged for professional help. 

Should there be a heavy down pour the water will at least be guided out towards the front of your property and not pool towards your BBQ area or backyard.

If you have any other questions we can help with, please let us know.

Eric