HELP: Water drainage problem!!!

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Beny

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#218053 24-Jul-2017 01:04

Refer to this Drawing: https://ibb.co/eCSg25

I have attached a picture of the problem area, hopefully I haven’t confused anyone with the busy drawing I produced or this long post for that matter. I included the water mains, fiber cable and power just to show where they are in relation to the problem. The drawing is not to scale but the layout is fairly accurate.

Like many, our lawns flood when we get heavy down pours, as what much of the Country experienced over the last few days. The land slopes down from the front to the back so we end up with a small swimming pool in our front yard. The problem is, that pool of water ends up cascading under the house. I only noticed it when I happened to go under the house to investigate some squealing noises, a stray mut had pups under there (some idiot left the access door open) not to mention it ripped down some of our underfloor insulation. Anyway, I always assumed the pooling water would just filter underground which is not the case. The water to the right of the footpath flows to the back (as per drawing) so not a problem as theres nothing obstructing the flow unlike on the left (see the chimney). Where the water goes under the house, there is a drain pipe which is sitting on top of the ground until it exits near the back of the house. This drain pipe comes from the gutter on the roof.

So, question is, what would be the best course of action to divert the pool of water from flowing under the house?

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#1828069 24-Jul-2017 02:06

What type of outside walls do you have? Concrete or brick ring foundation or just fibrolite to ground level? I see that you already have lots of responses to your trademe thread.

timmmay

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#1828079 24-Jul-2017 06:47

My lawn has channels dug through it, with stone chip, drainage coil, more stone chips, then soil and grass. You can do this along walls too, dig a trench and add drainage. It's not going to be perfect but it should reduce the water going inside.

Another thing you can do is dig down to the bottom of the wall, paint it with a sealer like tar paint, then put the soil back. This depends on the wall type and will rely on drainage to take the water away.

Coil

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#1828081 24-Jul-2017 07:17

I was thinking something like this if you have a concrete foundation. You may need to waterproof and that can be expensive but well worth it!

The picture above has the idea of what im talking about. Maybe not buried under earth but a scoria pit with drainage pipes in it. Maybe you may need to trench above the house to capture water flowing off the road? I would assume that water flowing around a slab will slowly start to erode the footing so time maybe of the essence!

kryptonjohn

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#1828103 24-Jul-2017 08:56

We had serious water coming through our basement. A small amount was leaking into one corner of the downstairs slab so it had to be dealt with.

The solution is to dig a trench the full width of the house on the uphill side (in our case by shovel in the basement) deeper than the bottom of the slab, behind the retaining wall. The retaining wall was then covered with a waterproof membrane and drain coil at the bottom of the trench connected to cesspits then into the storm water system. Then the trench refilled with scoria.

That was a difficult and expensive job, but we got it done before some of those huge autumn weather bombs and the basement stayed dry so it has worked.

There were drains in place, but they were 60 years old, not enough aggregate in them and the old field tiles were blocked with clay.

Water seems to travel through fissures in the clay so you never really know where it is coming from. But in the end gravity rules, and if your drain is up the uphill side and deeper than the slab you should be ok.

kryptonjohn

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#1828104 24-Jul-2017 08:59

Our drainage is like what Coil posted - only the aggregate column is to the surface, and the whole thing is in the basement up against the basement retaining wall.

I pitied the poor buggers from AWF who spent a week in the basement digging clay with shovels. Man did they earn their not very good pay.

Beny

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#1828120 24-Jul-2017 09:09

Aredwood:

We have fibrolite to ground level. Yeah got some responses on TM. The general consensus there is to fill in the low spots so the water doesnt end up under the house.

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Bung

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#1828137 24-Jul-2017 09:17

How much of the water comes down the path compared to rainwater landing inside the boundary? Can you experiment with some sandbags across the gate?

In heavy rain we have water running down the side of the house then down onto the lower section. In our case it isn't going under the house. Most of this water come from the footpath above the gate and the grass berm once it gets saturated. A small slot drain on the path would capture most of this water but would be awkward to drain. The further down the section I go the easier it gets to connect to the drains but the slot drain becomes longer.

DarthKermit

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#1828185 24-Jul-2017 09:51

timmmay: My lawn has channels dug through it, with stone chip, drainage coil, more stone chips, then soil and grass. You can do this along walls too, dig a trench and add drainage. It's not going to be perfect but it should reduce the water going inside.

@timmmay, have you found your lawn drainage to be effective? I wanna do something similar to ours.

timmmay

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#1828189 24-Jul-2017 09:56

DarthKermit:

I find the channels quite effective. We have clay soil, with 10-20cm of better soil on top. Before we did this we'd get a pool over our lawn fairly often. Now it very rarely does that, only with extended heavy rain, and it drains reasonably quickly now. I go around with a big garden fork one a year and put lots of little holes in to help it drain, particularly over where I know the channels go.

I also did this alongside my shed, along with tar paint. It significantly reduced the water coming into the shed, close to eliminated it.

Also, I found something odd quoting your post. When I hit "quote" GZ isn't actually copying your text into the edit field. @freitasm a bug or a feature?

tchart

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#1828203 24-Jul-2017 10:05

Beny: We have fibrolite to ground level. Yeah got some responses on TM. The general consensus there is to fill in the low spots so the water doesnt end up under the house.

Yeah did this at our old house. Was a bog when we moved in. Filled it in and sloped it ever so slightly. Worked a treat.

+1 for the drainage channels too (source: I used to be a civil engineer).

Beny

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#1828240 24-Jul-2017 10:48

Bung: How much of the water comes down the path compared to rainwater landing inside the boundary? Can you experiment with some sandbags across the gate?

In heavy rain we have water running down the side of the house then down onto the lower section. In our case it isn't going under the house. Most of this water come from the footpath above the gate and the grass berm once it gets saturated. A small slot drain on the path would capture most of this water but would be awkward to drain. The further down the section I go the easier it gets to connect to the drains but the slot drain becomes longer.

The path is slightly higher than the grass so none of it comes down the path, just run-off from the grass areas.

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Beny

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#1828251 24-Jul-2017 10:51

I just want to know if putting one of those catch basins (as per Youtube link: https://www.youtube.com/watch?v=cuPKb_2KtTw) in the lowest spot and hooking it up to the stormwater drain pipe that runs under the house is allowed?

timmmay

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#1828256 24-Jul-2017 10:57

Why would you not be allow to put drainage on your own property? That would be quite effective if in the right place. I have this type of thing all the way down my driveway. For the lawn though just channels under the surface.

Beny

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#1828262 24-Jul-2017 11:16

timmmay:

Why would you not be allow to put drainage on your own property? That would be quite effective if in the right place. I have this type of thing all the way down my driveway. For the lawn though just channels under the surface.

It will be the easiest solution, just want to make sure if its perfectly fine so Council doesnt end up on my case, afterall, its just run-off water going into a stormwater pipe.

kryptonjohn

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#1828274 24-Jul-2017 11:48

I don't think you're allowed to just go ahead and hook into the council stormwater system by yourself. It will need to comply with certain design rules, probably with stuff like cesspits, be permitted and be done by a registered plumber or drain-layer.

Otherwise you'd get cowboys filling up the stormwater system with silt etc.

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