french drain (confused)

[rcrcomputing]

I see, when you look up french drains on google, you can see 40 differant sites with 40 differant ways to construct one.

Here's a short list of things I've found.

use concrete sand (no filter fabric needed)
use gravel (Harder to work with, need fabric)
When using fabric, some sites say also to put a "sock" around the pipe as well.

Some sites say just put fabric on top of the gravel and not all the way around gravel.

Soooo, needless to say, I'm confused on the best method to use. Though the "sand" with no fabric does look like an interesting way to go...

Thoughts?

 

[txdon]

To add to your confusion /forums/images/graemlins/grin.gif:

Here is a link by the Energy and Environmental Building Association. On page 68 it discusses perimeter drains.

Filter fabric surrounding coarse gravel surrounding (above and below) perforated pipe.

It also says in the book, (and I did not realize this) you should also have a granular drainage pad of coarse gravel under the basement slab and have a pipe connection, through the footing, connecting to the exterior perimeter drain. (A connecting French drain on both sides of the footer.)

Interesting topic, I will be following it.

 

[marks]

This drain thing can be somewhat confusing, however it is time well spent in doing the research and designing a system that meets your specific needs. I've gained a tremendous amount of insight from this web site, and hopefully you will find it of value as well. http://www.ndspro.com/technical_info/index.aspx

 

[PILOON]

OAround here we uses the socked black drain that comes in coils.
First we make sure that the bed is flat, clean and below floor level which generally means flush with bottom of footings.
About a 3" bed of 3/4" crushed stone is then raked flat and the socked drain pipe is laid.
Over that we lay about 6" of same crushed stone and cover the stone with textile fabric (landscape fabric.
In the old days layers of straw were used and more recently the brown (grey) felt paper was also used.
Reason for textile/straw/felt is to keep out fine sands and clays from blocking the drain field.

You have not mentioned where this drainage goes but you need to provide a site somewhat downhill to recieve this water.
A gully, drainage ditch or slopey area is fine otherwise you need a field, very like a septic tank field to absorb this seepage water.

Don't go cheap and do use both the sock and textile as it will pay off in the long run, besides the cost is quite low.

The idea of 'TEEING" in the floor gravel os deffinately a good one, otherwis provide a seperate run for the floor drain.
And yes, it is standard practice to have a 4-6" layer of crushed stone under a poured floor for drainage.
Some guys also lay 6 mil poly before pouring the floor against dampness. Concrete pourers hate that as the concrete cures much more slowly but is is better way to go.
You also want a 6X6" wire mesh otherwise the concrete will have cracks in it.

In cold climates some folks use high density foam boards under the floor. Makes for more comfortable floor temps.

 

[rcrcomputing]

</font><font color="blue" class="small">( This drain thing can be somewhat confusing, however it is time well spent in doing the research and designing a system that meets your specific needs. I've gained a tremendous amount of insight from this web site, and hopefully you will find it of value as well. http://www.ndspro.com/technical_info/index.aspx )</font>

That is a good informative site. Thanks

I'm making a "perimeter" drain. My hill leaks. /forums/images/graemlins/smile.gif
Ditch is about 2 1/2" deep. 150' long and varies between 14" wide and 24" wide.
I'll take pictures today so you can see the rocks I pulled out. Still need to slege a few in the ditch. /forums/images/graemlins/frown.gif I could dig em out, but they seem to be about as big as my car...

Slope is NO problem, it's all down hill at a sharp rate. I end up in a pond.
I already bought some corrugated plastic pipe, so I guess I'll go buy some socks for it (or landscape fabric to sock with if it's easier than slipping a sock over it.) 2-3 inches of gravel under the pipe, 7 inches gravel on top of pipe. All wraped inside a filter fabric.

I see the article, (and others here) suggest making the bottom of the ditch flat. Umm, NOT. I don't have a rock sander... hehe So I guess the gravel underneith the pipe will have to create the "flat" part.

Also, I don't ever want to create something I can not drive over. According to what I read. I'm deep enough to not have to worry about it.