Linear French Drains

i have a home on the bottom of the hill. I get a good amount of water under the house. Approx. 75X25X3. I have installed a water pump that now exist to the street. I have dug out trenches in different directions leading to the pump. Now I want to add 3 or 4 inch perferated pipe. Here is my question. I only have 3 feet clearence. What is the best way to attack this. Getting the stone down to the crawl space would be a huge undertaking. I have the "stocking" to place over the pipe. Must I use the stone? Should I use 3 of 4 inch? What way do the holes face (up or down?) I can't do much more on the outside of the property, for I havent any access.

All of your questions have been answered in many of the columns in the Drainage category of my website.

I'm having a problem with water coming through the cement block in front of my house.It runs under my house to where I have a gas hot water heater.It builds up around the heater and puts the pilot light out.I have had french drains put in the front to where the water starts to come through the block,and it has not helped any.Now somone suggest gutters.I'm tired of spending money to get the problem fixed and it's not being fixed.Do you think gutters would solve the problem?

Gutters will surely help so long as that water is piped far away from the house by gravity. Also, you better make sure the french drains were installed the way I describe above. If not, start over.

I'm having a problem with water standing against my basement wall. Every time it rains 2inches or more, the water comes up above my crawlspace. At first in came through the basement walls. i tried to seal them with a sealant. It held for a while and then it started to come up over my crawlspace which is about eight inches above the ground. Do you fell that this french drain could work for me. Also I'm getting water from a hill!

Sherrita,
Read all of the columns in my Drainage category and follow all of my advice. Your basement will stop leaking.

dear Tim,

Thank you for your help! Did you know that I only had a two feet clearance on the outside of my crawlspace. It was rough trying to dig the trench but I made it. I had help. I know that you said the holes in the pipe should face downward but my friend installed in wrong and then covered it with gravel. Should I remove the gravel and reinstall the pipe?

Sherrita,
You should be fine. It is not the end of the world they are pointing up.

Dear Tim,

I wanted the trench to be exact so we removed the pipe and started over. Four days ago it rained extremely hard. I got the chance to see and hear the trench in action because I hadn't replaced the top soil. It was amazing. My basement was dry Too! However I did notice one problem. There is a void againt the basement wall where I have a crack fixed and water was against the wall. Should I refill this with dirt and slope it toward the trench or what should I do?

Sherrita,
I *told* you it would work!!! Congratulations!!!! Yes, you need to fill the hole and slope the earth towards your new drain.

I am very impressed by the working of the french drain. I intend to have a basement room which will be 8 feet or so below ground (garden) level. I want to have the stairs (from the garden level) leading to a small patio (which will just in front of the basement room). My contractor tells me the stairs should be in the room since ther is no drainage for the rain water etc. Can a french drain solve the water drainage problem? Please advise.

Rebecca,
The patio will need a field drain that either drains by gravity to a low spot on your land, or the water will need to be piped to a sump where it will then be pumped to a gravity drain.

Sear Tim, When it rains any about a half inch or more I have about a foot of water or more in my crawl space. We have a house next door about 15 ft away but it sits up hill a ways about 4 to 5 ft. The previous owners put 6 mil plastic down but that does not seem to be helping any answers?

Larry,
Read all of my Drainage category columns and follow my advice.

I just installed a french drain the way you described and it seemed to be working. In cincinnati, we received around 5" of rain over a 2-1/2 day period. My basement was dry for the first day and a half and then after so much rain I had water come into the basement. Someone told me that I should have installed the french drain as deep as my footer. Is this the case? I installed it 2 feet deep along the problem area like you said and still (eventually) had water come into the basement. Any suggestions?

Thanks, Ryan

How does grass grow if you have washed rock 1 inch from surface??

What is the tip about playwood? Also, have read that 8"-12" drains are sufficient? Why 2 foot trench?

Ryan,
They can be installed that deep, but here in Cincinnati, that is unnecessary. Remember what I said about the clay soil. My guess is that you water problem might be related to negative or minimal slope around the foundation, roof water that is not piped far away or some other surface-water issue.

Scott,
The grass grows with great ease in 1 inch of soil.

Scott,
Are you trying to pimp me? :-> I answer all of these in the body of the column as well as other columns about the topic. I also need you to use your noggin......

I have a dry basement, bone dry and no evidence of leaks or flooding ever. BUT, our sump pump runs an awful lot during periods of heavy rain & snow melt. I've thought about building a French Drain and read your articles - here's my problem: My driveway slab is immediately adjacent to one side of the house. On the other side, my neighbor's lot line is too close to go out more than 31/2 ft. AND the land slopes downward in a steep grade to my neighbor's yard (my home is much higher than the neighbor's). The grade is also ever so slight from the front of the lot toward the back. I assume from reading your articles that putting in a French drain system that is L shaped to carry water to the back will minimize the amount getting to my sump pump - or am I just crazy and should be thankful for the sump system and its running often is it doing its job? My neighbor extends her downspout right up to where the slope ends and her lot line begins. Could this be why my sump pump runs so much and would installing the French Drain JUST along this side tapering downward to the back work to divert her water despite the slope? Finally, the previous owners put in a raised flower bed off a rear screen porch. The raised bed is 9 ft from the foundation wall. Water does not appear to be running toward the house at all from the bed on the surface (it is always dry under the porch), not even when it rains. Is it possible though, that water might be soaking into the ground and THEN running back toward the house from this bed? The regular ground level is graded away from the house sloping backward all the way to the yard of the neighbor behind me.

Anne,
You just need to protect the high side and whatever else you can. It sounds like the drive side is out of play because of slope. You should install one of my Linear French Drains to minimize your dependence on the sump.

I just recently noticed a horizontal crack in basement wall. We have a negative slope and have water problems...My question is if we put in a french drain, do we not have to worry about the horizontal crack? Is it possible to devert the water problems soon enough and we don't need anything structurally done to the basement wall?

Celeste,
You fix the negative slope, install my LFD and then monitor the crack.

Hello, I have been reading all of your drainage topics and I believe that a french drain would work as you describe for my basement. My house sets on a hill and it leaks from only the uphill side, so I was just going to do a fench drain along that side of my house to catch some of the water and run it out the front yard by the street. My problem is that my driveway is 2 feet away from that side of the house and you said that it should be 4 to 6 feet away. So my choices would be to put one in 2 feet away or 12 feet away from the house. I thought that 2 feet would be better because my driveway has settled and almost tips toward the house, so the water runs mainly towards the house off the driveway. Do you think it would still be ok to put it 2 feet from the house or do you think it would pull to much water towards the house?

Joel,
If the drive slopes towards the house, then put it on the house side.

Tim, I live in central New Jersey and the land on the right-side of my house has a small pitch going from the front of the house down towards the middle part of the rear of the property. I have an in-ground swimming pool towards the rear of the property. The other side has a driveway. So, I cannot really divert water to a lower part of the property. Is a sump pump my only alternative? How will the water get into the sump pit if it is located inside the house (I have a French drain in the basement inside the house) or under a planned basement entrance which will extend about 5 feet from the house? The entrance will be enclosed (weather-tight but unheated). Should I be concerned about freezing in the sump pit? Also, would I need to pump the water towards the front-of the house where it slopes away from the house toward the street (where I live, they don’t allow draining storm water in the sewer line)? Can the 1.5 inch pipe from the pump be installed underground and come out at the front of the house?

Dennis,
There has to be some point on your lot that is the lowest point. This comment area is meant for quick answers. It seems like you might need a 15-minute phone consult. Consider it.

I have just begun to install a french drain system. I have 4 groups of Crape Myrtle trees along that side of my house (slabe) that needs the drain. Heavy root systems as the trees have some years and have deep roots. On your website you state the trench should be 24" deep, is that a minimum? My thought is that I will also need to run this drain along 2 sides the West and North side of the house. The West side will need to have the drain system run the full length of the house while the North side should only need 1/3 the length because the property naturally slope with a negative grade to the east. I have some issues I must consider and do not know exactly how to address. #1 1/2 the length on the west side has a large flower bed that takes the natural slope of the property and I don't believe I can create a negative slope on that side or take the grade 6" below the foundation line. #2 the othe 1/2 fo the west side has a two car garage entrance which also take the property slope. My driveway runs North to south and is nearly level but does have a slight slope toward the house and garage entrance. Do you think if I installed the french drain on the west side of my driveway (no obstructions) which is approximately 25' to 30' from the house and garage entrance, that it would control the water coming from the natural slope of the property?

Victor,
The system needs to be on the high side of the house and wrap around to exit towards the lowest part. It is that simple. Read all of my Drainage category columns.

I have a problem where I beleive I need alinear trench built. The question I have is that the only place to run the tile is to the bottom of the ditch in front of my street. I was wondering if there is any chance that water would come back up my tile i put in the ground. I thought about running another tile for another 10 or 15 feet down the ditch just to make sure I get the water the right way.

will this work?

Dear Tim,

I have read all the drainage columns and am about to begin installing a linear french drain and had a few questions:

1) Since this will be part of my front yard, is there a drainage advantage to using the straw method you mention vs. filling all the way with gravel and laying sod on top? Will the sod grow laid directly on gravel?

2) If using 10 ft PVC pipe (perforated) do the pipes need to be sealed when connected?

Thanks in advance,

Kevin

Tim, I appreciate all your articles. I've spent a lot of time and money trying to fix my drainage issue. I hired some hands to install a french drain before reading your advice. The perfurated pipe that I had laid was right up next to the house instead of 4-6' out. I thought this was the place to put it, besides, when homes are constructed, don't builders lay their pipes right at the foundation? At either rate, the water infiltration into my crawl space grew worse. THEN I read your advice postings. I learned that putting a perfurated pipe right next to the house would actually draw water to the house...and being that the pipe was perfurated, well, with a constant flow of water, a good portion of that water was bound to be coming through the holes in the pipe. Long and short, I've hired the installers once again and they've dug a MUCH deeper trench using a mini-backhoe. And the trench is about 4-5' away from the house. My question is this: the trench isn't a mere 6" wide. It's more like 18" wide. This won't pose a problem will it? It will be filled with gravel to within 1" from the top. After they finish and it rains hard, I'll be sure to give you an update. Thanks again!

I have read through the articles, but I didn't find a definitive answer to my question of whether a 24" deep french drain will be deep enough to remedy my situation. My foundation walls are approximately 4 ft. poured concrete below ground, and water seems to come up through the settling cracks in the floor and the seam where the wall meets the basement floor. I'm fairly certain it is ultimately caused by runoff as I have only about a 6 ft positive slope away from the house that immediately turns to a negative slope from the street. So would a 2 ft. deep trench remedy this or would it need to be as deep or deeper than the footer? thanks

Is it okay for me to tie my gutter downspouts into a french drain around my house?

I had a french drain installed along the north side of the house in hopes of stopping water from coming into the basement. My slope was neutral or negative. The drain was dug about 4 feet deep, the perf pipe was placed on top of the soil, and the gravel covered about 2 feet and finally covered with 2 feet of soil(the plumber/contractor wanted it done this way). With the first big rain, the basement was dry. The following week, and with subsequent moderate rains, it leaks. Would you recommend fixing the slope problem and what is the likelihood this will work?

Tim,

Your plans and advice worked great for us. My son and I ran a trench across our front yard to catch water that was coming at our foundation on the front. The system works very well. Our basement is dry. We did cut some squares and placed gravel (looks like step stones) at the top to catch heavy surface runoff. Thanks for everything. Your advice saved me a boatload of cash.

Pete

We are going to have to install a french drain to redirect standing water next to our foundation. I was just wondering if the end of the pipe (where I want the water to be redirected to), needed to end up above ground? It just seems if you leave the end of the pipe underground, it would get clogged with dirt and gravel as you refill the trench.

Jennifer,

Reading some of Tim's other articles on Linear French Drains, he does mention that the end of the pipe must daylight or exit above ground. This will allow the captured water to run out of the system.

This sounds dumb, but I sure would like to use the top portion of a 36" electrical wire trench as a shallow French drain, carrying water down hill to meet the major french drain. Is there any way I might use build a French drain to go no lower than 18", when the data lines are buried at 24" and the electrical line are buried at 36"?

My backyard is rather flat and about 3 ft below the Easterly neighbor. When they over water, they flood our backyard. On more than one occasion, they have left their sprinkler on all day and we had a swamp in the yard.
During the rainy season....let's just say we have a lake.
How large of french drains should we build?
I was thinking of an intricate 3 to 4 large pits connected by perf pipe, eventually exiting to the curb.
Our backyard is ~50' x 175' enclosed on all sides.
Thank you,
Jeff

How far from the foundation do you put the trench? and why?

Hi Tim,

Your site is excellent, thanks! I want to finish a sub-basement which had waterproofing done. I believe it was a french drain as all along the walls there's new cement and a half inch gap between the floor and wall. Two questions:
1) While there's no water per se, the pump still runs a lot, and it seems the gap is 'moist' so I'm afraid to put wood and drywall, let alone a floor...what to do?
2) I sometimes get weeping from the walls and lots of efflorescence. I'm interested in using a product called Krystol, which I hear good things about. I'm also working on regrading around the problem area, but would like to know your thoughts about the wall.

Thanks again for the site, and in advance for your answers!

Tim,
I seem to have similar problems others have too. My problem is that my crawlspace has pools of water in it. There is a perimeter drain with 2 sumps with sump pumps around the foundation and they do run qutie frequently. The problem is the center of the crawlspace is lower than the perimeter drain I beleive and hence I get water there. I beleive the water table it a bit high. This wasn't a problem last year but we have put in a lawn about 20 feet to the south of our house and in order to get the lawn going we watered it a lot. I had some pro's out to give me an estimate on what it would take to fix it and some were quite high. I then found your site and beleive I can attack the problem myself. There is about 3 fee or so of space in the crawlspace. My thought is to put a linear drain around the 7 concrete caissons in the crawlspace and put the top of the perforated pipe at the top of the caissons and then run this drain into the existing sumps. I have plenty of depth to do this in the sumps. The crawlspace soil is clay. Can I just dig the trench put in the pipe and cover it with the soil and be done or should I use gravel in the trench? Thanks.

Scott

Tim,
I just bought my first house. My house sits below the road. When we have heavy rains the rain comes from the road, down the driveway towards the house, which then come in through the basement. The water comes in through the window cracks, and small cracks in the wall near the floor. Luckily the previous owner built a french drain around the inside of the basement. So most of the water drains out through the french drain along the inside wall of the basement.
(I recently bought a de humidifier and that has worked wonderfully to dry out the walls, then it rains again and I back where I started)
My concern is all the water that come in from the tiny wall holes/cracks and the window.
I had two excavators come look and give me an estimate. The first excavator wants to dig a 3 foot french drain along the front of the house to divert the water and wants to add gutters to catch the water draining from the roof. (I am concerned about the gutters freezing up in the winter) This would cost around $4000 to do.
The other excavator wants to dig a french drain 8 feet deep, same level as the basement floor, then tar the exterior basement wall.
This would cost around $15,000 to do.
Both excavators would extend their french drain around the side of the house, and the water would drain down hill into the lake.
My question is do you really need to dig all the way down to the basement floor level, it all sounds good, taring the exterior wall ect..
But I don't mind spending a little more to have the job done right. Any help you can give me would be greatly appreciated.
Thanks,
Kip

Hi, We've been having a problem with water in our crawl space and basement (which are at the same level) since we moved into the house a few years ago. Our house is in a low spot, in a flood zone, and whenever nearby creeks overflow after heavy rains or melting snow, we get water. It doesn't appear to seep through the walls, but seems to come up through the concrete floor. We've had a number of waterpoofers over, but they all seem to be mostly interested in selling their product. So, we're not sure what might be the best way to approach the problem. Should we waterproof from the inside or outside? All those inside systems sound great when the salesman is pitching it, but we've heard a number of horror stories too. Any insight will be greatly appreciated! Thanks.