French Drains

What is a French Drain?

The French drain is an underground drainage system that comprises a sloping trench filled with gravel, a perforated drain pipe, and covered with drain rock and landscape fabric. Its primary function is to collect water from areas where it is not needed and channel it to a safe location. This could involve safely running it off, absorbing it into the ground soil or pumping it away. French drains are versatile and can be used both inside and outside of the house. When dealing with drainage problems, nothing else is an adequate substitute for a French drain. It is an effective and reliable solution to various drainage issues, regardless of the location or magnitude

 

When do you need a French Drain?

Are you struggling with issues such as stagnant water in your yard, dampness in your basement, or a damaged driveway due to water accumulation?

If you live in an area with a high water table or heavy rainfall, you may need a French drain. You may also need a French drain if your property slopes towards your home, causing water to accumulate in your basement or crawl space.  

 

Oftentimes a French drain becomes necessary because a previously installed drain has failed.  We have seen this all too often, and have dug out more failed drainage systems than we care to count.  This is why it’s important to hire a contractor that specializes in french drains designed to last!  

 

How to Construct a Drain That Will Last

Here at Pacific Earthworks we build French Drains that will last.  Each project has its own unique set of environmental challenges that can impact the longevity of a French Drain, and we do our best to be aware of what those factors are and take them into consideration when designing a drainage system.  

 

We believe the staples of a good french drain system are:

1.  To ensure the drain is located in the appropriate location.

2. Gradually slope the drain at a consistent grade.  We always use a laser receiver when excavating our drains to ensure consistent grade throughout the entire trench. 

3. Don’t over-dig!  It is easy for anyone to get in a hurry when excavating a drainage trench.  However if the trench is over dug anywhere through the drain system, the pipe can sag in that spot.  Even if the area that was over dug is filled back in with dirt, unless the soil is compacted properly your subgrade of the drain system is compromised and eventually the pipe placed on top of that spot will bend in a slight U shape.  This can cause your drain pipe to crack and inhibit the flow of water through the drain.  That’s why when we are digging our drains we take our time to make sure the subgrade doesn’t become compromised.

4. Use a high quality non-woven geotextile filter fabric that will not disintegrate as rapidly as some of the cheaper options that are available.

5. Wrap the entire trench including the drain rock in the filter fabric, not just the perforated drain pipe.  This way small soil sediments will not infiltrate the pipe as readily as other construction methods. 

6. Use a quality drain piping that will not crush under pressure.  Yes it can cost more per foot, but what’s the point of installing a drain pipe that will be crushed flat in just a few short years?

7. Utilize larger diameter rounded drain rock that has been washed.  This type of drain rock provides excellent flow rates of water through a system, and the rounded gravel allows for less capturing of small sediments that may be present in the water running through the system.

8. Don’t utilize high clay soils for the cap of the drain.  Yes the drain can be hidden from view and the drain rock does not have to be visible from the surface, but if this construction method is chosen it is wise to make sure that the soil on top of the drain will let water pass through it to the drain.

9. Always make sure rodents and other critters can’t enter the drainage system, it is more common of an occurrence than one might think and can cause early drain failure.