A French drain is a versatile solution for managing excess water on your property, preventing flooding, and protecting your home’s foundation. It consists of a trench filled with gravel and a perforated pipe that redirects water away from the flood-prone area. To install a French drain, dig a trench from the area that needs drainage to the chosen outlet, ensuring the proper depth and location.
When installing a French drain, the holes in the pipe go down, allowing water to flow from the gravel below into the pipe to be carried away from the flood-prone area. If using a corrugated drain, it is recommended to have two drains at the retaining wall. Outside drains are best but typically difficult and expensive, while inside drains are easier and cheaper.
Exterior French drains are typically located along the exterior perimeter of a building’s foundation and serve to collect and divert water. The drain should slope away from the house, ideally at a slope of 1, or 1 foot of fall for every 100 feet. To mark the path, use spray.
Interior French drains are installed underneath homes at the outer edge of the foundation and are generally patched with sealant. An inlet grate should be installed at the spot where significant water pooling occurs, which is where the French drain begins.
In summary, a French drain is an effective solution for managing excess water on your property, preventing flooding, and protecting your home’s foundation. To install a French drain, dig a trench, ensure proper depth, and choose the appropriate location.
📹 Testing French Drain Scenarios To Find Out….Fabric or No Fabric? Which Is Best | Dr Drainz
Welcome Back To Apple Drains in North By Go Carolina We have been running this experiment for a couple of months on 3 …
Where should a French drain be placed?
French drain installation is a gravity-assisted method to keep a yard free from excess moisture. To install, create an artificial slope by digging at a 1 gradient. Lay water-permeable fabric around the trench sides, followed by adding rocks inside. Place perforated pipes with holes facing down for easy water flow. Fill the trench with rocks until slightly above ground level. Cover the entire drain with the remaining fabric.
A suitable French drain installation location is usually around the house, as it redirects water away from the foundation, protecting it from moisture. This method ensures the yard’s water is directed away from specific areas, ensuring maximum effectiveness in draining the yard.
Are exterior French drains effective?
Both interior and exterior French drains provide flood and water protection in basements. However, due to the high costs and difficulties associated with installing and servicing exterior drains, it may be more beneficial to install interior drains.
Does a French drain need an exit point?
The ideal French drain installation doesn’t need an end point, as excess water from one area is distributed more evenly across the yard and absorbed. This means water doesn’t need to be dumped anywhere, but ends up in the soil along a better line of distribution. Accurate Lawn Leveling can help you choose the right French drain for your yard or foundation, ensuring the necessary drainage is installed.
Should a French drain be next to foundation?
A French drain should be installed 4 to 6 feet away from your foundation to prevent water accumulation. However, the distance may vary depending on the landscape and the severity of your water problem. Ensure the drain slopes away from your foundation to divert water properly. Improperly installed French drains can cause foundation problems by directing water towards your foundation, causing water seepage and potential damage.
A French drain must be deep enough to effectively divert water from your property, typically 18 to 24 inches. The precise depth depends on factors such as the severity of your drainage problem, property slope, and local building codes or regulations.
Do French drains have to lead somewhere?
The French drain should end near the lowest point of your trench to redirect water away from areas prone to flooding. A long pipe should be used to redirect water to dry areas, such as a drainage ditch or soakaway. The drain should empty into a less prone area. Proper French drain installation involves careful planning, proper installation techniques, and proper drainage to ensure the best possible outcome.
Will an exterior French drain prevent water in the basement?
An exterior French drain is a crucial component in basement waterproofing systems, directing water away from the foundation and preventing it from seeping into the basement or crawl space. Common locations include along the foundation’s exterior perimeter, downslope areas, driveways and patios, and around access points. These drains help prevent water accumulation and improve drainage in areas where water tends to pool.
A French drain is essential for basement waterproofing as it minimizes excess water near the foundation. If the pitch of your driveway causes water to pool near your home, it can cause issues in your basement. To determine the proper placement of your exterior French drain, a thorough understanding of your property’s water management issues is necessary. If you have any doubts, it is recommended to consult a professional waterproofing company or landscape contractor.
Does a French drain need a membrane?
Installing a French drain is a simple process that requires careful planning and attention. To ensure proper drainage, use a non-woven membrane, plan the trenches correctly before digging, and use perforated land drainage pipe. This method can be modified to suit your unique circumstances. If you’re not comfortable installing the drain yourself, consider hiring a local landscaper, groundworker, or drainage engineer for a quote.
It’s essential to use a minimum of one gradient and ensure that the trenches are properly drained before digging. If you’re not comfortable with the process, consider contacting a local landscaper, groundworker, or drainage engineer for a quote.
Should a French drain go inside or outside the crawl space?
The French drain is a crucial system that redirects water away from the foundation and out of a home, preventing it from reaching the crawl space. It should typically go outside the crawl space, as it can cause costly damage if water enters the space before being drained out. Although it is possible to install a French drain inside the crawl space, it may not be as effective as when installed outside.
It is considered the last line of defense against water damage, designed to prevent water from collecting around the foundation. Proper installation ensures the system works as intended, resembling a moat around a home, but instead of being filled with water, it keeps the water out.
What are the disadvantages of a French drain?
French drains can have several drawbacks, including the need for regular maintenance, potential damage to utility lines during installation, and difficulty in locating and fixing clogged pipes. They can also cause flooding in homes if ponding water occurs near the foundation, damage to pavement in driveways, and ruin landscaping. Additionally, standing water in the yard can make walking across the yard difficult on rainy days. Therefore, it’s crucial to carefully consider the potential drawbacks and consider the best drainage solution for your specific needs.
Can you put a French drain next to concrete slab?
The installation of a French drain around a slab foundation can serve to prevent the upward displacement of water, thereby preventing the phenomenon of heaving.
Should a French drain be sloped or level?
In order to effectively utilize the force of gravity, French drains must have a slope of at least 1 percent. This necessitates a slope of at least one inch per 10 feet of pipe.
📹 Do NOT wrap a French Drain Pipe With Drainage Fabric
I want to talk a little bit about the pipe we use, the fabric we use, how we use it and why we use it in the way that we use it. So a lot …
My family owns a $10M landscape and design company and everything he said about the fabric is correct. He just showed you why. It’s the better way to do it . If you choose not to that’s your prerogative but it will be prone to packing the stone which must stay clean for best results. He never said without fabric it wouldn’t work. It’s a difference of quality and life of the drain working well
This is about the 100th article I’ve watched about clay and fabric and I’m still confused. I’m thinking about just doing it with rock alone. A filter is a filter… wether it is a fabric filter or a rock filter, wether it is non-woven or not. If it’s filtering the clay, where does that filtered clay go??? and they all eventually clog. Seems like a fabric filter would clog much faster than rock… I’m leaning on using 6″ smooth perforated PVC pipe with 90 degree sweep elbow clean outs on each end, (round grates on top) and just run a pressure washer drain snake attachment through it every couple of years. Surround the pipe with about 1″ rock. The smooth pipe bottom should help it clean easier?? Seems like the rock might tend to clog from the top anyway, and not the sides or bottom, due to gravity… I’d rather deal with that down the road than pulling the whole thing due to clogged fabric.
We usually place the “non-woven” filter fabric along the bottom of the trench, place some #57 stone in the bottom (3-4inches thick) place the pipe and cover it with 6-8 inches of stone. Then wrap the stone with the fabric to create a “burrito” effect encapsulating the stone. This prevents soil from getting to the pipe from all directions, top, sides and bottom. Then backfill the trench. In commercial use we backfill with mason sand or concrete sand above the fabric.
Great article, great idea for testing, great effort … You get an A+, sir. Couldn’t help notice though that the first setup, sans the landscaping/drainage fabric, seemed to have the fastest throughout by far, but I guess you mentioned that was bc it was dry and subsequent storms would find the clay compacted. Well, thanks bud, we appreciate it. Btw… I’m standing outside over a couple sections of new corrugated pipe wondering how many drill holes to put in it, where and what size (thinking 3/16ths or 1/4″…?)c right here in good old WILMINGTON, NC
I’m In Massachusetts and I used to install septics. Schedule 40 is what is used for all piping. It’s actually very strong and if it cracked in the winter I’d imagine every septic in the state would have failed. There is a solid pipe that is pretty thin walled which you might be referring to but schedule 40 has about a 1/4 inch wall.
On one side of my yard (neighbors house is higher) I have a wood retaining wall but the water runs towards my house and saturates the gravel and even gets into my crawl space. I run corrugated solid pipes from my gutters on this side and run to front of the house. Im thinking about putting a concrete slab here to slope surface water away from my house and so I can have a solid pipe under the slab for the gutters. While this may mitigate surface water ( especially if I had some surface drains on this slab that connected with the gutter pipes) will this mitigate sub surface water from my neighbor? Is there such thing as putting a French drain pipe under slab or would it have to be on the edge of the slab at the foot of the wood retaining wall? Thanks.
Sorry, but I’m gonna say this wasn’t done right for any of them except the basin. #1 Any French drain that’s installed should have the stone compacted, then the Dry surface soil compacted over it, (and if composed of clay) lightly wetted, compacted again, then sod placed (or topsoil/straw and seed sown). This has been a standard procedure for over 100 years for most long-term contactors who have done foundation work in high-clay soils. By compacting and wetting, the surface solidifies into a semi-solid mass. Even when it cracks from drought, it self heals, especially with covered by sod. Been very well documented. You basically rigged the results by not doing any of the above. #2 ALL filter fabrics clog in high clay soils. Tried them all, they all clog in the same way after only a few rain cycles. The water is clearer in your example because the fabric is already starting to clog. The flow is also notably decreased in the article and will continue to decrease over time. #3 Basin/surface drains should be installed in tandem with properly installed French drains. You get major points from me here. #4 To avoid ANY concerns over soil cogging: Leave drains exposed as part of rock path or rock barrier/garden around homes.
i do not understand how water pushes up to the pipe. In a situation of a 10 foot retaining wall will the water have to back fill up to the French drain? I don’t understand “fill from the bottom”. Sure in a plastic container, where else could it go. So using a sealed plastic container, sure, it fills from the bottom. But with a 10 foot retaining wall the water should just keep going down until it back fills the depth of the retaining wall.
Looks to me like this proves you should NOT use fabric. As your demonstration shows, the clay is taken away by the no fabric drain, The tiny particles of mud cant clog a drain pipe but can clog a fabric filter,. SO the clear water coming out of drain using fabric means that such a system keeps the clay on site. So it appears that stone without fabric only gets rid of BOTH the water AND the tiny clay, particles – which is what stops water form flowing in the 1st place. But I aint a pro. so take my observations with a grain of salt
Thanks for a great demonstration! It is very interesting to see how the fabric keeps the clay particulates from clogging the gravel. But in your article, there was no clay underneath or alongside the lower level of gravel (that encircling the pipe) – just the plastic of the bin. I live in Ky., and have to deal with hard pan clay. Obviously, I’ll have clay on the bottom and along the sides of the trench – not plastic. I am building more of a curtain drain (shallower trench alongside a sidewalk, for the runoff). In the situation of short, “average” rainfall, I was counting on the stone to hold the water until it gradually percs into the clay. In a heavy downpour, because the clay percolates slowly, it’s going to act more like a french drain. I plan on placing a 4″ perf. flex pipe on a bed of small, smooth river stones, then fill with gravel and top with pea gravel for the look. I am not using any soil in the back fill. So do I use fabric or not? Using the logic from your demo, it would seem that using fabric on the bottom and sides of the trench would be needed, to keep the clay on the bottom and sides from eventually clogging up the websites in the gravel. I have looked at so many Apple Drain articles with Chuck that my head is spinning about what to do…. Any advice is greatly appreciated! BTW I am a 63 year old woman and doing this by myself!
I’m going to do something like this around my house since I’m missing some gutters and can’t get anyone out to put them up on my two story home. I don’t have fascia either and I just had my shingles replaced I would rather not screw straps on my shingles. Any thoughts on the correct drain methodology, I was thinking corrugated slotted pipe with rock and a sleeve like a burrito 😆can I get your professional thoughts on the correct drainage methods and products to use for this. Thank you in advance! 🙏🏼
Seems like the best way to do this is dig your trench put your fabric down in the trench put your pipe on top of that pour your stone on top of the pipe all the way up to the top leaving a few inches of space for the sod, then burrito wrap the cloth so no stone is showing after that lay your sod down.
The reason why fabric does not work is because the clay and silt run out of the soil ontop and at the sides of the fabric, it doesn’t happen straight away it takes time. If you have a dispersive clay soil as I have found out the hard way fabric or no fabric they both have huge issues. I’m not quite sure how to fix it and resolve the issue but to say other people are incorrect isn’t entirely true because actually brand new fabric will take the water away but do the same experiment after its been in there 12 months…. The fine particals blind to the geotextile and instead of blocking the inside it blocks the outside instead. I would be grateful for your reply because I am telling you that this is 100% true and I am living in a nightmare.
Update: To reiterate: My goal was to divert surface water from the the sidewalk to a drainage system. I have it emptying into a small drywall about 16″ – 18″ deep and 30″ wide. Now, I am about 1/2 way done. My drain system is really more of a curtain drain, and not a true French drain, because it’s very shallow, only about 8 – 10 inches deep. The whole thing may be overkill, but even when I just had the dirt trench there, the water ran off well – but the trench gradually silted up, so a more “permanent” solution was needed. Oh yeah, and I am 64 in November, so if I can do it, anyone can! What I did was this: 1) I bought the 6 oz. fabric from the supplier that Dr. Drainz recommended. It was good, solid stuff. I have trees and shrubs in the immediate area, so I figured anything to slow down root penetration is good. The water will still make it into the drain. 2) Laid a 1 inch layer of “river rock” (bagged smooth stone, about 1/2 – 1 inch in size). I emptied one bag at a time in my Dad’s (65 year old Craftsman) wheelbarrow and rinsed it with a garden hose, then slowly tilted it so the murky water ran out. Did this about 5 – 6 times till the water was about 1/2 clear. 3) Laid the 4″ perforated pipe (not the ADS, just the flex pipe from Lowe’s/HD). It has perforations spaced all around the circumference, so no worrying about getting the right side down. 4) Covered it all with the small river rock, and did a burrito wrap with about 2 inches of overwrap and used landscape pins to secure it.
If you pull the surface water out right at the beginning, then why do you need the French drain? Won’t the water make its way down eventually and find its way to the French drain? More importantly, don’t you want that water to make its way down into the sand/clay to keep the grass watered? Don’t you run the risk of having to water your lawn more with the third option?
im thinking about using the NDS ez drain pipe it has the pipe wrapped and poly rocks wrapped around it already but im curious if i should use another layer of fabric on the bottom then lay the pipe down or is the fabic that comes around the pipe good enough? my soil is dirt on top about 10 inches down then i have clay .
Every soil is different .Just because you’re saying no fabric is bad, don’t make it true.. the first drain is flowing quickest and best.. the fabric in the two demos is already slowing the water from percolating into the ground, getting to the bottom of the container. I’m not sure 3 years from now that fabric wont be clogged. The water is sitting on top of the last two demos because of the fabric
For a retaining wall, would you not place the fabric down first then place the stone, then pipe, then more stone all the way up until the last foot or so of a wall with the fabric fully wrapping the stone from the bottom all the way up? I have clay and also see very different ideas on how deep the drain should be. above the footer, or at the first level of block below the wall grade?
It’s going to rain more than a bucket if it has fabric wouldn’t it start puddling up on top and it won’t drain as fast so you would still have that problem puddling and sometimes it rained hard for almost an hour seems better almost without fabric fill it up with gravel to the top but will look bad I don’t know just wondering
I just last week installed 4inch perforated pipe . Trench 1.5mtr deep layed taram covered in 1 mtr clean 20/40 hardcore and wrapped only about 6inch below surface. First rains and the discharge pipe is dripping. Had too cut fabric on surface to allow water through as was totally clogged with silt. I regret laying 150mtr with fabric now.
It is my understanding that any professionally engineered system will specify washed drain rock AND a fabric barrier. If fabric really became sealed, then all the retaining walls would be failing due to hydrostatic pressure. IMO fabric doesn’t seal from clay. Water goes through clay. Otherwise the water would never even make it to the fabric.
I put in a drain system around garage and along driveway. Worked fine it seemed until neighbor and I put in driveway gravel and it ended up a little higher than the driveway and muddy water ran off gravel onto the driveway. I uncovered the drain and replaced everything on top of the fabric with washed drain rock so the runoff will not reach concrete driveway. Flows like an open pit now but the rocks get displaced a little. Lesson learned, don’t cover french drain with dirt or driveway gravel.
I have a garden space that get’s flooded by the property next door. My back yard id sunken and is sitting on a shallow clay base. To keep it from flooding I have a sump tank in the lowest point which worked fine until the building next door was demolished leaving the concrete slab behind. I was going to install a small french drain system in the garden and take it to the sump but was wondering if solid pipe with surface drains would work if the drains were connected by perforated tees. The idea is to avoid fabric and stone by using a solid corrugated pipe. Soft soil wouldn’t be a problem if I can remove standing water.
I have a flat pathway, only 4 feet wide. Brick is about 1 feet below the ground. The brick sits on large stone. My house is on one side and the other side has a fence. The other side has ground. I don’t have slope. The tube would be level to the ground. Can I use a sump pump with a french drain to pump away the water? Any other tips for this situation?
You have to remember, a french drain is most effective at taking care of the low volume subsurface water (a soggy yard). If you do not use filter fabric, you lose all the air voids in your drainage stone, making it much, much less effective (almost ineffective in fact). Just don’t expect any french drain with sod on top to take in flood water. Bulk surface water is what 12 and 20 inch catch basins are for.
On a project I’m working on the ground has very a high clay content. I wish to run a drain some 250′ on slightly sloping ground. I do not wish to back fill with soil/clay but rather just leave the rock exposed. My idea is to line the trench with fabric first, lay 3-4″ of rock in and then 6′ corrugated perforated pipe and back fill with rock. Has anyone had experience with this scenario? Any thoughts on this is appreciated.
Great article and explanation. Thanks! I just moved up north to clay soil which is very different from florida I have a weird situation with standing water in back yard due to issues in my development. I was thinking to put a french drain in but fill with rock or rock the bottom then backfill with potting soil just to keep the water underground in hopes of having a bit of a dryer yard. I really have no where for it to drain off to. If this doesnt work i may have to put in a basin and a sump pump also at the end of the run. In your opinion could my idea keep the water underground? Or am i way off in my thinking. Thanks, again
I had to redo the french drain behind a retaining wall behind the pool, but used fabric from Home Depot. The drain had absolutely no rocks around it and was buried directly in clay. It was so bad, muddy water was passing through the retaining wall and went directly into the pool every time it rained. What is even crazier, is that the previous owner who had it all installed was a professional landscaper. I’ve lived here almost a year and I’m still getting court orders due to his dissatisfied customers. A cop even showed up at my front door once looking for the guy. The pool pump wiring was another fiasco I had to completely redo, then there was cut through irrigation, etc. I’d have to say, I’ve learned alot from another person’s mistakes!
Find a textile source that will sell you non-woven geo fabric. What we normally use runs about 5-8 dollars a foot 12 feet wide rolls. If you encapsulate the ditch with the fabric, 2″rock base, 4-6″ perforated corrugated or pvc, covering the pipe with 4-6″ rock, overlapping fabric, and be sure to tamp the rock base and fill as you go….. it’ll drain and you’ll be happy you used the fabric. We also use the pipe with drain sock installed as well. The ground water grates can tie into your French drain which helps keep the pipes flushed. We have ran into some jobs where there was so much ground water pushing up air vents where required to prevent the drains from being overtaken. Surface grates work well for this until the ground water reaches the drains and there’s a heavy downpour or long periods of rain. Gotta have air behind the system just as the plumbing in your house.