Actual Civil Engineering Work ... well kinda

I got tired of tripping over the 2 gutter downspouts on the side of the house so i decided to make underground drainage. Here's the first one on the side of the garage.
Step 1. Dig the trench. To go under the concrete i used an ice auger.
dig trench for roof drain, gutter, rain water

Step 2. Fit the pipeshow to install a roof drain, trench, gutter downspout

Step 3: Backfill with sand
sand backfill, roof drain, materials, pvc pipe, cap
10' PVC pipe ----------------------------- $8
10' PVC pipe with drainage holes ---- $8
cloth pipe cover ------------------------ $6
drain cap --------------------------------- $3
two 90 degree bends ------------------ $2 each

I did buy two of everything for the drain in the back yard which, i haven't finished yet because i had to chisel through the concrete and drill a lot farther with the ice auger.
The bad part is that my yard is all clay, which doesn't let water drain. So i had to use sand to backfill around the pipes.


Anonymous said...

How stupid. Is this what they do in your country? Don't you have sewers? You're going to let the water just seep into the ground? Say hello damp to your house.

Notitlerequired said...

A few things:

- If i didn't do this, water would come out of the gutter and pour onto the ground right next to the garage. By adding the 20' of pipe i am at least moving the drainage point away from the house, and slightly down hill.

- If i didn't do this, water would seep into the ground anyway, and right next to the foundation.

- The storm sewer's here only drain the water once it reaches the street, through catch basins. I believe back 30 or 40 years ago there used to be 4" drain pipes that connected from the house gutters to the storm sewers. The problem with that was whenever there was a heavy rain, storm sewers became overloaded and caused a backup.

Brian said...

Looks good! Thanks for posting. My only questions are:
1) does water get trapped because of the bend up at the end?

2) Does debris fall in the grate?

3) Can the grate be removed for clearing?

Notitlerequired said...

Yes water is trapped, but eventually drains trough the weep holes and through the sand.

No i haven't really had a problem with stuff falling through the grate. If it does i can just take off the grate, reach in, and pull stuff out. Actually i have had to do that once or twice to pull out a handful of leaves.

Just remember the more slope away from the building the better.

Unknown said...

Great vid and documentation.

I live in a similar climate. I think the previous poster was hitting the right point. A primary difference between your method of extending a drown spout and other approaches are weep holes vs T’s that drain into open space below. Another difference is pvc vs corrugated

You’ve now got 5 years of experience and at least 4 winters. So….
Does you method drain fast enough in your soil so that you don’t have a frozen downspout extension most of the time in the winter?

2nd. Do you still prefer a corrugated vs pvc?

3rd anything you would change in method or materials in retrospect?

Thank you for all of your help

Notitlerequired said...

So far i haven't had any frozen downspout extensions. It seems like in Michigan the gutters freeze before the downspouts or drain pipes.

If i had to do it again i would have gone with the Corrugated HDPE pipe. It's cheaper to buy and easier to install. You don't have to bother with elbows and making sure the trench is straight. The bendable pipe means that you can run it anywhere you want in just 1 piece.

One thing i would do differently is add more sand. In my yard it's about 3" of topsoil then all hard light gray clay (which water doesn't drain into). I would get probably 1-2 yards of sand per drain, dig a bigger trench and fill it up with the sand before setting the pipe.

MO said...

Hi, I have an ugly above ground drainage spout (L shaped) extending about 6-7 feet......real ugly. I've been searching for ideas on how to extend drainage underground and I'm glad I found your link.

1. Do you need to have drainage holes all along the pipe or gravity alone is enough for water to come out of the grate?
Making 2-3 small holes on the bottom of the 90^ elbow near the grate to drain any accumulated standing water sufficient? Basically I'm not comprehending why drain holes along the pipe.

2. How much $$ difference between PVC and corrugated pipe? Is corrugated pipe strong enough not to collapse under the weight of the top soil?

Thanks in advance for your feedback.

I got here from your YouTube "garage shelves" video which I'm going to be building soon.



Notitlerequired said...


I think it would work without the drainage holes, but water would constantly be in the pipe. And the elevation at the grate would have to be lower than the elevation where it connects to the gutter, otherwise it would flow out at that end. Only on really heavy rain days do i see water kind of bubbling out of the grate. Usually after an average rain i will open the grate and look down to see just a couple inches of water still in the pipe, then by the next day it's empty again.

I forget the cost difference between PVC and corrugated pipe. But i do know that the PVC was more. Plus you have to buy all the fittings you will need and cut the pipe where you want bends. As long as you aren't driving a car over the pipe it shouldn't be a problem in terms of collapsing.

Like i said earlier, the corrugated pipe is just way easier. You only have to buy one thing, no connections, it can bend and curve to where ever you dig your trench.

I just bought something like this: 25'

But you can buy a more heavy duty roll at home depot or Lowe's that comes like this:

MO said...

Thanks for your response. The grate will be a lot lower than the where it meets the gutter/downspout. I figure I drill 2-3 small holes about half an inch apart underneath the 90 bend that's connected to the grate and put a cloth screen where holes are to keep debris out. So when it rains light or heavy, water will come out of the grate aided by gravity and when it stops raining any remaining water in the pipe will drain slowly out of the bottom holes.
I'm getting so many ideas off your blog.

Anonymous said...

Thanks for the post. Here in Oklahoma we have red rose clay, acts like glue when wet and hard as a rock when dry, so you have to pick your battle when to dig. I noticed you only used sand as a drain fill for the pvc with drain holes. We added a small septic tank for our kitchen last fall due to plumbing issues which I will not get into, but we used what my husband called septic gravel, which was just a large gravel. He dug the lines out put the gravel down, laid the pvc then put garden cloth over the lines to prevent grass from growing into the lines and covered with dirt. It has been right at a year we have had a monsoon of rain this year (right about 43" from Jan to today in July) the ground has not dropped as a matter of fact there is still a crowning where the lines where laid. Not sure if the gravel was the reason why but for the amount of drainage it was a must. Today I start to dig for the down spout French drain. When we bought the house 2 years ago all but two corners of the house had French drains, there are even two on the detached garage but no gutters (??), why you ask? So have we. Anyhow, today I am starting to dig one of the last one that has guttering, the other need guttering and then a drainage system. Glad I saw your post because I wasn't sure how far to take the lines out. Thanks again, Rhoni from Oklahoma

tony said...

in my town they want us to direct spouts to your yard away from house,no more down spouts attached to sewer causing water backup on heavy rain,good idea dave,yard looks cleaner with pipe buried.

Len said...

Dave,you said in retrospect you would have uses HDPE pipe. It looks like you used PVC in your application. We have a clay soil here in NC.

1. Do you think HDPE would be best?

2. Do you recommend filling around the end of it with send where the bend is and the emitter? I assume the rest of the pipe can have clay soil around it since it is not weeping through until the end of the pipe, right?

Notitlerequired said...

I just like HDPE because it's easy and can bend around roots and things.
And i try to buy perforated pipe and put pea stone and sand in the trench. The drain cap is only for heavy heavy rain as an overflow. Most of the time it rains it doesn't come out there (i think) it just drains through the holes in the pipe. But ya if i didn't add sand it wouldn't work since i have clay here too.

mikkydee said...

I installed similar drainage to gutters on my previous home. Used the underground pipe with holes in it to disperse the water in the pipe. Very bad idea in my experience. Roots found their way to the holes and eventually completely stopped up the drainage pipe. On my current home I used 4" PVC (unvented/no holes) and directed waterflow about 50 feet away from the home with an 90 degree elbow to turn pipe back up to ground level. Pipe stays full of water unless more water is diverted into the pipe from gutter in which case it pushes water out. Pipe staying full of water keeps critters and debris out of drainage system. Been doing great for 12 years with no issues.

Josh Vega said...

I did a similar setup, but I have a 12" catch basin 10 feet from the house with holes in the bottom to drain over gravel. It then extends another 10 or so feet to another smaller basin, also with holes in the bottom, with a grate on the top to allow water to exit during heavy flow.

My current concern is if this caused my downspouts to freeze to the point that I'll have an issue when all the snow thaws.

Unknown said...


Thanks so much for posting this with pictures and info. I also appreciated that you answered the comments with more good advise.