Why wrap top of french drain

[lpranger467]

I understand using landscape fabric under a french drain to keep particles and such out, but I dont understand wrapping the fabric over the top of the corrugated pipe. Wouldnt that slow ground water from getting thru and entering into the tube ? Thanks

 

[davesl708]

Hi. Welcome to TBN.

You need to wrap the whole pipe to keep the silt out from flowing in from above. The fabric will let water pass easily.

 

[Welshman]

Hi. Welcome to TBN.

You need to wrap the whole pipe to keep the silt out from flowing in from above. The fabric will let water pass easily.

This has always confused me. Doesn't the fabric eventually become clogged from the silt?

 

[RNeumann]

You understand putting fabric under the french drain to to keep partials and such out? Logic has left the building........

 

[MossRoad]

You understand putting fabric under the french drain to to keep partials and such out? Logic has left the building........

You want to keep false teeth out of the pipes?

 

[MossRoad]

I understand using landscape fabric under a french drain to keep particles and such out, but I dont understand wrapping the fabric over the top of the corrugated pipe. Wouldnt that slow ground water from getting thru and entering into the tube ? Thanks

The fabric wrap keeps silt out. Think about it.... water washes silt into the drain channel. Water washes the silt down through the drainage material to the TOP of the pipe. The fabric prevents the silt from entering the pipe from the top. So the top fabric is probably more important than the bottom.

 

[Welshman]

You want to keep false teeth out of the pipes?

:laughing:

 

[rswyan]

On the off chance that the OP isn't considering actually burying the french drain and is considering leaving the top open:

Bad idea ... the french drain should be completely buried to remove subsurface water.

Draining surface water is an entirely different thing ... and a different drain.

 

[EddieWalker]

The way a french drain works, the water goes to the bottom of the trench and then flows through the pipe from the openings in the bottom of the pipe. You are not trying to catch the water in the top of the pipe, you want the water to go around the pipe until it pools up at the bottom and can flow away. The top of the pipe should be as water proof, and debris proof as possible. If not, it will quickly fill up with debris and become clogged.

 

[boggen]

the french drain pipe is not laying out in middle of no were. example in basement with nothing around it.

french drain is not laying in a specific channel. with nothing around it.

the french drain is covered up and buried.

normally french drain = trench dug -> french drain pipe with holes in it -> fabric -> rock -> dirt -> grass

the fabric helps keep the rock out of the holes, and the rocks help keep the dirt from plugging and making a solid formation around the drain pipe. all of which helps allow water to get into the pipe.

its when you start messing with a french drain. re-digging it backup or like. and you start mixing dirt and rock, and/or you did not properly compact the rock/dirt around the french drain. were you can get additional issues. granted there is still "fines" small dust like particals that still make it through. but generally limited and small enough that they just pass right on through everything and go out with the water.

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google
diy sand and gravel site:koiphen.com

the S&G filter. uses layers of different size rocks, grates, and eventually sand on top. it might help ya understand the layering.

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you might look at gravel driveways, were a larger base rock is placed down first, and then smaller size rock is tossed on as a final touch. the larger rock will not sink into the dirt, while helping hold the smaller rock on top.

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french drain, fabric, rock, dirt in how it is layered and installed, is creating a filtered layers that allow water to flow downwards and eventually lets the water get into the pipe.