french drain mistakes

1. Why do French drains fail?
2. Do holes go up or down in a French drain?
3. Can French drains fail?
4. Can you put topsoil over French drain?
5. How deep should you dig for French drain?
6. How long will a French drain last?
7. Do French drains need to be sloped?
8. Does a French drain need an exit?
9. Do French drains really work?
10. Where should I put a French drain?
11. Can you drive a car over a French drain?
12. Can you cover a French drain with mulch?
13. What is the difference between a French drain and a trench drain?
14. What size gravel is best for French drain?
15. What is the best fabric to use for a French drain?
16. How much does labor cost to install a French drain?
17. Can a drain pipe have too much slope?
18. Can I use river rock for French drain?

Why do French drains fail?

This issue could be due to clogging. When water seeps through soil to get to the French drain, it often brings along sediment into the drain, where it dumps the sediment in the drain on the gravel as it flows through the ditch.

Do holes go up or down in a French drain?

When you lay your PVC pipe, the rows of holes should always be facing the downward position. You want to keep the water level in your French drain as low as possible at all times, and you can't achieve this if the holes are facing upwards or sideways.

Can French drains fail?

However, inspectors may want to know more about this method of preventing flooding on a property because French drains may fail and subsequently cause visible signs of flooding at the exterior of a home's property and potential moisture intrusion problems that affect the home itself.

Can you put topsoil over French drain?

The simplest drain is a classic French drain, which is nothing more than a trench filled with coarse stone or gravel. ... The drain can be left open or, if aesthetics are a concern, can be covered with a couple of inches of topsoil and sod.

How deep should you dig for French drain?

French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.

How long will a French drain last?

How long do french drains last? Properly installed drains use advanced plastic sheeting called geotextile to protect the drainpipe from a blockage. French drains can last decades before needing maintenance. If your home requires a sump pump, a high-quality model will last around ten years before needing replacement.

Do French drains need to be sloped?

French drains need to have a slope of at least 1 percent, so the force of gravity will work for you. This means that the drain should slope down a total of at least one inch for every 10 feet of pipe.

Does a French drain need an exit?

No Acceptable Exit Point

If you can't find a good place for your system to drain, you'll need to empty your system into a dry well. A dry well is a vertical hole, typically about 4 feet deep and 1 foot in diameter, that's filled with gravel. A dry well lets excess water be absorbed by the surrounding soils.

Do French drains really work?

Properly constructed, french drains will work well to transmit water from the pipe to the exit of the pipe; however, they are not very efficient in dewatering poorly drained soils. Adequate fall means at least 2 ft lower per 100 ft of pipe or 0.25 in. per foot of slope.

Where should I put a French drain?

Dig a trench along the outside of your footing. The trench should be at least 2 feet wide, and can be as deep as 6 feet for a basement or as shallow as two feet for a slab-on-grade home. Lay the pipe on the virgin soil.

Can you drive a car over a French drain?

French drains are used to remove excess water from an area. ... The PVC piping only needs to be 4 to 6 inches in diameter for draining purposes. It must also be rugged enough to withstand the weight of vehicles driving over it.

Can you cover a French drain with mulch?

Since a French drain can be covered with turf or mulch after installation, it's also virtually invisible. Though the traditional design simply was a gravel-filled trench, you'll obtain far better results by employing a drainage pipe, landscaping fabric and a few high-tech tweaks.

What is the difference between a French drain and a trench drain?

The terms rhyme, they both involve trenches, and French drains aren't really French. The defining difference is very simple, however: Trench drains are surface structures while French drains are subsurface ones. Let's look at how they both work to keep water flowing offsite.

What size gravel is best for French drain?

For the best drainage, look for coarse washed rock (gravel) that is screened, with a stone size of 1/2 to 3/4 inch. Smaller rock with fine particles could clog the holes of the drain pipe. Pea stone works, but the smooth stones settle together and don't move as much water as coarse rock.

What is the best fabric to use for a French drain?

Quality woven, pure polypropylene soil fabric has always been preferred for French drains, soil stabilization, ditches, and pipe-in-gravel, chamber and mound septic leach field systems.

How much does labor cost to install a French drain?

An exterior French drain is only installed two to three feet deep to help move the water away from your property, making it less labor-intensive to install, costing about $10-$15 per linear foot for parts and labor with an average cost for installation around $1,000 to $1,500.

Can a drain pipe have too much slope?

Improper drain slope

The ideal slope of any drain line is ¼ inch per foot of pipe. In other words, for every foot the pipe travels horizontally, it should be dropping ¼ inch vertically. ... That's right, it is possible to have too much slope in your drain lines.

Can I use river rock for French drain?

Hard rocks such as granite or river gravel prove viable options for a French drain because they won't break down over time as much as other rock varieties, such as sandstone and limestone.