Drainage Question

Murphy

Hey I'm not sure if I should post this here or not so feel free to move it or bash it or whatever.

I am going to be installing the 4 inch PVC drainage lines with the holes in it. I would like to install it upside down with the holes at the top. With the cloth sleeve and covered with rock.
Will this make the system fail? What are the problems with doing it that way.
The client lives on a golf course and the runoff all comes into her backyard. I am planning on removing a bunch of grass about 3ft wide all along that side and installing the pipe in trench lined with landscape fabric, and covered with pea gravel then cover with river rock.
I don't do this but the client has asked me to do it for her and I have a tough time saying no because I need the money. big job just cancelled on me.
Any advice would be appreciated.
Murph

tgeb

Well you probably did post in the right spot.

I recommend the holes at the bottom. That's the way I do it. In this type situation, the pipe is to carry the water out of the area. If you put the holes at the top...then you have standing water around the pipe that needs someplace to go.

I think you are taking the right approach on this problem, just put the holes down.

Others may have a different opinion, let's see what they have to say.

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Tom

www.gebcon.com

Murphy

WIth that PVC pipe aimed down there are holes at the very bottom and I really dont want the water draining out. I need it taken from the problem area to a drainage ditch about 60 feet away. I was planning on surrounding the pipe with dirt so the water would hopefully find its way to the top.
But if that is a total no no I understand and I appreciate the reply. I just dont want it leaching out. In other places in the yard. It is a total mud pit right now.
Thanks Murph

tnmtn

definitly i would have the holes down. at first glance it seems to not make sense. but as it was explained to me 2 thoughts are at work. 1) water goes down with gravity, 2) water will follow the path of least resistance. if the water is not pooling in the bottom of the trench then it doesn't matter whether the holes are up or down. if water is pooling then it needs a way out. with the holes in the bottom the water will then follow the pipe out to your ditch like you want it to. through the pipe becomes the path of least resistance. also, less chance of debris or fines filling the pipe.
good luck,
metin

jmic

In different situations I'll rotate the holes to suit the situation at hand. By placing a few inches of stone at the bottom of the pipe the water will follow the path of least resistance and enter and follow the pipe to the discharge outlet anyways. Murph you ought to go to your local library and get a book authored by Denick titled " Everything You Always Wanted To Know About Drains But Were Afraid To Ask "

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Joe

Murphy

kind of my point if the water is taking the path of least resistence then why wouldn't it go through those holes and back into the ground instead of continuing down a pipe where it has to go over these speed bumps that invite the water to go down.

I am not a drainage guy but it would seem to me the physics of the pipe present a problem with the holes down.

But now I know if you guys do this all the time and holes down works then that is the way I should do it.
Thanks Murph

Murphy

Okay so if I lay it holes down do I have to put rock under the pipe or can I just lay the pipe on top of landscape fabric and cover everthing with rock?
jmic thanks for the info on denicks book I will definitely look into that, but I start the drainage tommorrow. I have already had the material delivered. Must be done before xmas so no time for more research.
I was hoping to pick the brains of you fine people

murph

tgeb

Well one thing you DO NOT want to do is tie your downspout drains and this drain together or consider as one, if that is the plan here.

Not sure what the plan is but your wording makes me think you may be trying to have a dual purpose here.

A drain system with stone to the surface as you have described would work well to dry out a lawn area where "pooling" or soft muddy conditions exist.

If you are also picking up roof drains (which could run in the same trench) they must be kept separate. That is, to run dual drain lines, the roof drains in solid non perforated pipe, and the lawn drain in perforated pipes bedded in stone.

I would lay a couple inches of stone in the trench over the filter fabric, then pipe and more stone.
I would not lay the pipe directly on the fabric. Or introduce more water by tying the roof drains into the stone system.

Let's keep going if this does not make sense to you.

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Tom

www.gebcon.com

denick

Murphy,

From your description I understand that you have a customer that has a backyard that is lower than a golf courses land. When it rains surface water runs over the land and into her back yard.

You are going to remove the sod across the back yard and dig a trench to catch this water and divert it away. You are going to line the trench with landscape fabric and place a pipe on top of the fabric and cover the pipe with pea gravel and the cover the pea gravel with river rock. From what I have read thats what I understand you are going to do?

Your question was about putting the pipe with the holes up. You have gotten good advice from the guys. The holes should be down in this case and in almost every other case.

I just wanted to add that you should start your thinking at digging the trench. If you have a large volume of water running down into this trench you may want to slope the upper side where the water will come from. This does away with any collapsing of the edge and siltation that goes along with it.

I will assume you will pitch the bottom of the trench in one direction for the water to exit.

Now you are going to line the bottom of the trench with landscape fabric? You shouldn't use landscape fabric! "Drainage fabric" or "filter fabric" is made to filter water and sediment "landscape fabric" is not.

You will line from the top all the way down and up the other side? This fabric is here to catch what? all the silt, grass clippings and leaves and sticks that will wash down over and down through the stone? Fabric in this type of trench is most importantly placed over the stone and pipe! I would buy a wide fabric and line the whole thing as you say but go up and over the pea stone and place the layer of river rock over top. make sure the water coming down the hill will not run under the top flap. The flap should go all the way to the lower edge. Silt and debris will build up on top of the fabric but in severe cases the river rock can be removed and the fabric cleaned and your drain will work for a long time.

Pea gravel on top of the pipe? I would use 1" stone, more voids more room for water to move. As the guys have said place 2" of stone on the bottom of the trench. On top of the fabric if you line the bottom.

Place your pipe holes down. Pipe in this type of trench drain only moves water in it when there is a high volume of water. Most rains if you put just fabric and pipe on top the water would be running on the fabric and not in the pipe. Now turn the holes up and you need 3" of water running in you trench that is 12" wide before it ever enters the pipe.

Cover your pipe with stone up to the level you want your river rock. fold the fabric over and place your river rock on top

I guess I just repeated what the guys have said.

Good luck

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Nick

"Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving" Albert Einstein

rino1494

Nothing else needs said here. Just put the holes down. Even if the pipe is level, the water will fill in through the holes and run out the pipe, as long as it is to daylight. Remember, water levels itself out.

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jmic

Rino,
Whats up? You ought to know by now unless you can beat Nick to posting there's not usually anything that can be said after.

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Joe

rino1494

LoL....... I think that he as a case of informative diarrhea when it comes to his posts

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Murphy

Okay so holes down. I lost my internet yesterday so I wasn't able to check the replies last night. Thanks for the info.
What I have is basically a t shape two lines on each side of a 12" drain to catch the water then one running off the back of the basin to run the water through the yard and to the culvert.
I am putting the landscape fabric down because the drainage line is only 4 inches my trench is maybe 5 + but I had to remove about 3 feet of grass. So I dug all the grass out and angled both sides to the trench, with plastic edging at the back to direct any missed water back to the trench. I figured I needed the landscape fabric to keep any thing from growing through the rock that will only be 1 to 2 inches deep.
The top of the T both lines direct into this basin at a good pitch and the back line of this basin runs about 60 feet to the culvert which is conveniently about 3 feet below the top of the T.
Sorry I am being so long winded but I just dont want to have to dig this thing up in the spring.
Will this work?
Thanks again for the input.
Murph

tgeb

I think that was an excerpt from Nick's book!

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Tom

www.gebcon.com

tgeb

As long as you run solid piping from the 12" drain to the culvert I think you will do OK.

If you need to collect more surface drainage then run 2 pipes one solid and one perf. from the drain box to the culvert. And bed both in the stone.

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Tom

www.gebcon.com

rino1494

How bout some pics ?

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Murphy

Sorry haven't taken any but it would look like this

30 feet long here 3 ft wide area with trench inside
-----------basin-----------
this side is |
nothing to worry about | 60 ft on this part emptying in culvert
here |
Sorry I am not that computer savvy. Hope this helps
I have more runnoff from gutter pipes not run into the sytem but into yard on right of the 60 ft. run to the culvert so I was going to use the black pipe with the 3 holes in it and a sock covered by rock then dirt.So they can grow grass back over it.

Murphy

The pic is screwed up and I have tried fixing it four or five times to no avail. the major drain line is off of the basin and it runs about 60 feet.

MC Excavating

Perforated drain pipe can and will never get all of the water off and away from the bottom of your foundation. Think about it guys. Water will always seek level. Water is self leveling. So, if you have a level foundation the water will gather towards your foundation because gravity will pull it through the soil to the top of your foundation and begin to fill that area up at a level rate of rising water and rising water pressure.

You should also use filter fabric or a filter sock to cover the pipe and protect it from silt build up and debris.

Now why wont perforated pipe remove all the water from the foundation???

Because when you place the pipe with the holes facing down (the way it should be) there is still about 1/2 to 3/4 of an inch from the very bottom of the pipe to the very edge of the opening of the holes on each side. Therefore there will always be 1/2 to 3/4 of an inch of sitting water on top of the foundation and if you place stone under your pipe this only increases the amount of sitting water before it can reach the drainige holes. Wtaer will not jump up and into those holes. It will daylight into the holes. Now of course when it stops raining or for whatever reason there is water gathering at your foundation it will eventualy dry out. Unless you have constant water issues.

Well what good does it do if it doesnt remove ALL of the water???

Think of perforated pipe drains as a pressure relief system. It allows a majority of the water to be removed to prevent extreme amounts of hydraulic pressure to build up and cause problems. Water is very powerful especialy under pressure. Water will always find the path of least resistance. So thats why we use perforated pipe instaed of allowing water pressure to build up against our foundation and water proofing and then finding the path of least resistance into our basements.

Should I put pitch or fall to the pipe?

I dont see why that would help. If your trying to get water off your foundation, raising the pipe on one end with gravel to get water to fall through the pipe will only allow a higher level of water to sit on the foundation before it can reach the holes. Then the water would have to travel along the foundation while rising at a level rate to find the lowest holes on the pipe before it can drain out.

Why use 4" perforated pipe at all, why not just use gravel???

Think of it like this. Your foudation is like New York City. Water is the people, cars and traffic are like the stone, and the subway is like the perforated pipe. So if you trying to get people(water) from A to B with the least amount of traffic and obstacles(rock) to get in your way, then the subway(pipe) is the way to go. When a major amount of water hits your foundation the pipe will then be the path of least resistance.

I am not an engineer, so this is just my theory on things. I hope it makes sense, because this is how it works out in my head.

What do you guys think?

concretemasonry

MC -

Great description of the operation of a well installed perforated drainage system.

I have 2 small items to add:

1. In some cases, you may have to install the pipe below home footings. It can be done, but the pipe will have to be set off from the face of the footing by an amount equal to the depth below the footing. This is usually adequate, but silty and some clays may require more. This is usually done when you have interior basement drain tile and are trying to "pull" more water out from under a slab with a poor base.

2. Any open drainage line can backfire on you. If the area you are draining into has a water table rise due to other drainage changes or a storm build-up, the water will obviously go the way you do not want it to go. - I found this out when making a temporary drainage ditch relocation over a long weekend. About 6" of unexpected rain plus another unknown change resulted in 4 home yards and basements flooded and an extra 20' of water into an abandoned irion mine. When the mine was drained, one garage went in also.

Dick