Red Clay and French Drains

[akita]

Wasn't sure where to post this so forgive me if posted it in the wrong spot.
I have a small area by the front of my house that currently has a Yoshino Cherry Tree, 4 Bordeaux Dwarf Yaupon Holly, and 4 Indian Hawthornes, and cypress mulch. This area is roughly 12'x14', give or take. The front half of this has adequate slope, whereas the back of it doesn't(think the shape of a hill or bell curve). The quick fix would be to dump a lot of dirt on the back end so that it becomes the high point and water can naturally roll off the slope, but that would force the dirt to be too high up against the house. I cant grade the front half to be lower than the backend as this would make that area way too low, not to mention that would be a ton of dirt to dispose of. The obvious concern is the water that sits on the back end that is closest to the house. I've thought of either doing the following:
1)Install french drain with pvc pipe,layer of gravel underneath and above pipe,fabric 2-3 catch basins, atrium grates
or
2)French drain pvc pipe only, gravel on bottom and top of pipe,fabric
or
2)No french drain, just PVC pipe+2-3 catch basins and atrium grates.

My concerns would be the fact that this drain would be installed close to the house(approximately 6-8inches from the house) and the effects of the french drain on the georgia red clay. Due to how close this is to the house, could this pose problems for the house(cracked foundation,etc)? Also, if I were to drill small holes at the bottom of the catch basins to help rid of any standing water, would this also pose any problems with relation to the georgia red clay and the house?

Thanks!

 

[MarkV]

Welcome to the forum. I would go with option #2. I have always found that the grates will clog up with leaves and such too easy. The water will move to the gravel and drain pipe naturally. Be sure to set the holes in the pipe on the bottom. They do make fabric socks that slide right over the pipes.

MarkV

 

[akita]

Thanks Mark for your comment. That definently is the downside to catch basins, which is the upkeep on them. I only thought of catch basins because the affected area is so close to the house and I wanted that water to carry out much faster than to rely on the water to seep in via gravel and percolate to the pipe.

Another question for all. How deep should I dig the trench? 8-12 inches?

I also noticed while I was at Home Depot that they dont have single row holes for pvc pipe. They only had 2 rows(on opposite sides) and no holes. Would there be a certain place where I can get pvc pipe that is just 1 single row or will I have to get a solid pvc pipe and drill the holes myself?

 

[JTKub]

If you don't think your soil has the ability to percolate water to the crushed stone and run down hill through it, I wouldn't bother with that route and address the surface water only. Go with just solid tubing/pipe with the catch basins if that's the case. A french drain with stone right to the surface (and no pipe or basins) is another option. I've seen owners use a nice colored stone up top to purdy it up a bit.

Joel

 

[2manyrocks]

You can buy solid PVC used for septic lines and then cut slots in the bottom in a miter saw.

Could you dig out an area that you would line with geotextile fabric, install your drain line, and then cover the whole thing with pea gravel as a kind of landscape feature. That's going to capture water for you.

 

[akita]

If you don't think your soil has the ability to percolate water to the crushed stone and run down hill through it, I wouldn't bother with that route and address the surface water only. Go with just solid tubing/pipe with the catch basins if that's the case. A french drain with stone right to the surface (and no pipe or basins) is another option. I've seen owners use a nice colored stone up top to purdy it up a bit.

Joel

It's not that I dont think the soil will percolate water to the stone and pipe, its just that im worried what will happen if the drain gets clogged(even if i use a sock and fabric) up by the georgia red clay in the future. Since this would be so close to the house, I would think if the drain fails, all that water would find a way to spread towards the house and compromise the foundation. Of course, this is just worst case scenario that I'm thinking of. I've also thought about surfacing that particular area with lava rock,river rock, or pebble while the french drain is underneath. So many decisions. Lol. Thanks everyone for your feedback

 

[JTKub]

akita, if you trench properly and add crushed stone before the pipe, the majority of the ground water should follow the trench (and run through the stones). The perforated pipe should only come into play when the volume of water is such that the level in the trench rises to fill the pipe, then flows out real quick through the pipe.

Joel

 

[2manyrocks]

Yes. The filter fabric is there to give you better performance out of the drain system and to avoid long term maintenance problems because it helps to keep silt and debris out of the drain pipe. Actually, you should wrap a section of the drain rock with filter fabric like a burrito so the drain rock doesn't silt up.

It makes for a better installation.

 

[grossgary]

I'm getting ready to install a french drain and don't understand how to make a decision on the fabric recommendations. If there's enough silt to cause problem clogging the drain pipe - then wouldn't that same silt also clog up the fabric? I'm confused about that. Seems like fine fabric would clog quicker than large holed pipe?

 

[2manyrocks]

Think of the filter fabric as a big wet towel. Somehow, the water soaks through, but the silt doesn't. The filter fabric you want is the heavy stuff sold to farmers and road contractors--not that lightweight box store stuff that comes on a little 3' foot roll.