Help with drainage problem.

weatheredwood

I need to run storm water drainage for an area where I laid patio blocks. I included a MS Paint picture of what I was planing on doing. I'm basically going to buy those box grill drainage parts and interconnect them with pvc pipe. I will run the underground pipe to a shallow trench at the edge of my property line. I have a few questions though.

-Do I need to slope the 4" underground pipe that goes to the trench?

-How much do I need to slope the patio blocks to the center where the grills are located?

-Do you have a better suggestion to remove storm water from this area?


Thanks

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weatheredwood

Can someone tell me if I am supposed to slope underground drainage pipe? Can I just run it level all the way across?

raam

Yes you do need to slope the pipe, otherwise how will the water get to the trench. I would slightly slope the pavers too, but if you prepare the ground underneath with a sand bed on sloped undisturbed soil or geotextile fabric, the water will permeate through and make it's way to the grill as well. Bump for more opinions.

terri_and_jj

pipe needs to be sloped. 1/4" per foot is a general rule of thumb for any drain pipe

I'm a little confused. are the pavers already down? what did you use for a subbase and how thick is it?

Bondo

Ayuh,...
And,..
Which way do the Pavers Slope/ Pitch,..??

weatheredwood

The problem I am having is that the trench is around 35 to 40 feet away from the first drain grill. The trench is only 6 to 8 inches deep. I can't really dig the trench deeper because of liability issues. I don't want my neighbor kid breaking his leg in the trench while playing. At 1/4in drop for every foot, I am looking at 10inches at the trench. This doesn't include the 3 or 4 inches under grade that it states off at. I would be looking at a trench at a minimum of 14inches. I thought it would drain if at level because the entire pipe is below grade. It would have to drain if it fills with water.

I haven't laid the patio blocks yet.

terri_and_jj

is there a reason you can't simply slope the pavers slightly, so the runoff is directed toward the trench?

water is lazy, if you don't slope the pipe, it isn't going to move.

raam

Can you not dig out the trench, lay the piping and then back fill with gravel afterwards. You need that depth.

Bondo

Ayuh,....

In That Case,.....
Alter the grade of what you have,+ pitch the water where you want it to go........
Raise the center of the courtyard, 1 end or the other,..??
Whatever it takes....

What's the Total vertical Drop from the existing Sidewalk, down to the Trench,..??

weatheredwood

I can't bury the pipe at the trench because the trench leads to the street. It would create a huge trap. I attached another picture. The water would have to drain because it will take the path of least resistance which is out the other end at the trench. I could have problems with stagnant water though. I can't really slope the patio away because there is a structure on either side. If I slope it to the trench, I will have a huge puddle in the yard every time it rains. The trench goes another 25 to 30 feet to the road. The first picture isn't to scale. The trench isn't that close to the building.

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so-elitecrete

leader drains regularly drain onto streets.

weatheredwood

How do I measure the drop? I was going to just pull some string across (sidewalk and trench). I would then put a level on the string and see what the difference is at the trench. Is this the right way? Also, How much should I slope the pavers to the center where the drain is? Is 1 in every 10 ft sufficient?

LawnGuyLandSparky

Are you saying that AFTER you dig a trench, you're going to leave it open?

weatheredwood

I am referring to the gully in between the property line. It is common to see them in this neighborhood. It is a very shallow gully because I get worried someone will break their leg.

Bondo

Ayuh,... A Sight Level is the Best,+ Easiest way......
As long as it's negative pitch All the way,....
Ayuh,... It'll drain......

Any Pitch, that's less than Dead Level will drain,.... How Fast is the only difference.....