Return to the Landscape Design Forum | Post a Follow-Up

 o
French Drain Design Opinions?

Posted by cpga (My Page) on
Sat, May 15, 10 at 16:23

Hi,
I am looking to install a french drain in front of my house. The problem is in the back, closest to the house and windows, where water sits. Part of the problem is due to the grading back there. I would have liked to dump a lot of dirt on that area to make it the high point so that water would roll off the slope but then that dirt would be too high and too close to the house/foundation. With that said, I was thinking to install a small french drain in that area. It would be basically 10ft by 12 ft approximately. The plan is:
1)Dig trench at a minimum of 8 inches(this would be the high point of the trench, where 10-12 inches for the low point of trench
2)Line trench with 2 inches of washed gravel
3)Lay fabric down with room to flap over pipe
4)Install 10ft of 4inch PVC pipe schedule 40(drill holes in a row to point downwards). 12 ft of solid pvc pipe will carry out the water collected to driveway
5)Place sock on PVC pipe
6)Gravel on top of pipe
7)Fold fabric over
8)Either top it all off with pebble, river rock, mulch, or dirt.

Notes & Questions:
1)Going to use 45 and WYE fittings. Will it be necessary for me to use PVC glue to secure fittings? Can I use tape of some sort instead?
2)Thinking of using 3 catch basins with atrium grates to expedite water capture. I have no problem cleaning out the basins when necessary as it is a small area. If I use catch basins, is the use of gravel and perforated pvc pipe even necessary?
4)At the low point, i plan on using a 90 or paired 45 to daylight pipe by the driveway. Angle it away from the house where the water will roll off the driveway naturally.
5)I plan on installing this within 6-8 inches of the house. Is this too close to install?

Attached is an image of what I have in mind. What do you guys think? Thanks


Follow-Up Postings:

 o
RE: French Drain Design Opinions?

What do I think? Once upon a time if you had a dental problem you either went to the barber or the blacksmith, either way the result was the same: no teeth. A detailed drawing of your mouth didn't ease the pain.

Analyze what the problem is and get local professional advice on how to fix it. In case I wasn't clear I don't mean your hairdresser.


 o
RE: French Drain Design Opinions?

cpga,

A very detailed idea of what to do. My appreciation is expressed.

1. No pvc glue is necessary especially if you ever have to dig up a line and clean it out. In soil there is plastic tape to wrap the joints in.
2. I believe you do not need a French Drain at all but a underground drainage system with catch basins. French drains are only necessary if you have underground flow of water not surface flow.
3. What ever works and your neighbors don't complain about you dumping water on their property or ruining their sidewalk. good luck with that. If you can under the sidewalk through the curb is best.
4. Too close and hard to maintain. Catch basins should be in the low areas and swales that you make to flow surface water over. Several feet from the house. Keep it all away from the house foundation. JMHO Aloha


 o
RE: French Drain Design Opinions?

Looks like listed my numbering wrong in my initial post, lol. Anyways, thanks lehua13 for your response. Yeah this water wont affect any of my neighbors. I guess the only concern now based on your comment on #4 is that it's too close to maintain. The area, which is probably 12'x12', is shaped like a small hill. In the middle is a flowering cherry tree and surrounding are a few Indian Hawthorne and Bordeaux Dwarf Yaupon Holly. The back area in between the house and where the pipe is in the picture has standing water(when I water the plants around there or when it rains. Otherwise, from the middle of this area and forward, there is adequate slope and water rolls right off.


 o
RE: French Drain Design Opinions?

How much standing water do you get in that area? Is it only when watering or also when it rains? Do you get water in the home? This could be just a simple thing as just regrading the area with a slight pitch away from the house. Or redirecting the rain water from your roof and dispersing into the lawn or garden bed.


 o
RE: French Drain Design Opinions?

I'll check the water level after it is suppose to rain today. As far as water level when I water that area, I've seen it rise just under that area above the foundation(so maybe a couple of inches maybe). Water does not get into the house. The water will eventually dissipate. The grading in that particular narrow part does not provide adequate drainage. The only direction to grade is either to the left or forward(this direction being the most optimal). Right in front of this area is a walkway that curves up to the doorstep and in front of this walkway is the lawn. I've crudely drawn a sketch of how it looks from the side. The red shaded area represents that narrow part where the water stands, while the brown shows the mulched area and the arrows show the direction in which the water runs off.


 o
RE: French Drain Design Opinions?

1)Dig trench at a minimum of 8 inches(this would be the high point of the trench, where 10-12 inches for the low point of trench NO
2)Line trench with 2 inches of washed gravel NO
3)Lay fabric down with room to flap over pipe NO
4)Install 10ft of 4inch PVC pipe schedule 40(drill holes in a row to point downwards). 12 ft of solid pvc pipe will carry out the water collected to driveway NO
5)Place sock on PVC pipe NO
6)Gravel on top of pipe NO
7)Fold fabric over NO
8)Either top it all off with pebble, river rock, mulch, or dirt. NO

lehua13 said:

"French drains are only necessary if you have underground flow of water not surface flow."

Read that three times. A French drain is not appropriate for your situation. Do not lay any perforated pipe in the location shown on your sketch.

Assuming that water would have flowed through the planed pipe to the drive leads me to believe that the drive is a minimum of 1 ft below the ground elevation at the far corner of the house. In which case no pipe of any kind is needed. Rake the mulch away from the house 18 inches. If the soil there is a spongy topsoil, replace the top 4 inches with a heavy soil type that can be compacted. Grade the 18 inch strip along the house for a uniform downward slope from the far corner of the house to the drive. Compact the soil and leave it free of mulch.

With the money you save, buy lottery tickets. If you win, email me and I’ll tell you where to send my half.


 o
RE: French Drain Design Opinions?

Thanks for your input.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Landscape Design Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here