Forum
« as below... Sandblasting Clawfoot tub feet »
March 15, 2008
French drain to waterproof cellar - how successful?
Anyone out there have success installing a French drain system? This came up in an earlier post I did about waterproofing a basement in a house we are buying but I'd love to hear from others who've actually used one. On my last visit to the house, the cellar was actually covered in 3 inches of water from recent rains, and the broker swore a French drain was the answer. Would love to hear more about these - how likely they are to succeed, rough cost estimates (footprint of this house is 16.5 x 40), good vendors to use, etc.
Advice greatly appreciated - thanks!
Comments
Are you talking about a true French drain (outside the foundation walls) or what's sometimes called an "inside French drain", which isn't really a French drain at all, inside the foundation walls? The former, which will prevent rainwater (but NOT a high permanent water table) from ingressing through your walls, is much more expensive than the latter, which really only collects the water that has already gotten in and takes it outside again, typically via a pump to the city sewer. Inside the walls it's acting as little more than an elongated sump pump scenario.
There's more on the difference here:
http://www.bobcats4hire.com/Drainage_Systems.htm
Posted by: johnife at March 15, 2008 5:34 PM
I myself would prefer the water not to come into the house in the first place.
The following has to be done first. Check the roof gutters to make sure they are draining into the sewer not the back of the house. Check the grade at the back of the house. Regrade if it does not direct water away from the house. Check the hatch over the back basement stairs.
Posted by: guest at March 15, 2008 7:37 PM
I used to live in a factory basement where water would literally drip down the walls when it rained enough Forming a 20' diameter lake about an inch deep in one instance. After four months of withholding rent and threatening to call The Housing Department our landlord installed an inside French Drain and it worked wonders. you need to keep air circulating and you can't really keep anything against the wall that it comes in from but it certainly eliminates the lake effect. . .
Posted by: bunkerlabs at March 16, 2008 12:28 AM
Friends in a brownstone on 10th street had an inside French Drain installed after a sump pump failed to work. The combination of the two has solved the problem.
Posted by: Jane at March 16, 2008 8:50 AM
"Check the roof gutters to make sure they are draining into the sewer not the back of the house"
DOH!--last week, in a comment on another post, I outlined all the steps I had taken over many years to stop water coming into my cellar. I even wrote some nonsense about the use of wells in Prospect Park lowering the local water table (which was probably true, but totally irrelevant). I just realized that it stopped completely only after I had my leader replaced, at the suggestion of a contractor who was painting the back of my house a few years ago . The old leader appeared sound from the front, but had holes in the back and crumbled when it was taken down--it was so old that it might have been the 100+ year old original. Not only that, but the water had always come in in the corner of the cellar where the leader ran. For some reason it never occured to me that the bad leader was the source of my wateer problem. THANK YOU 7:37. I feel dumb, but enlightened.
Posted by: Bob Marvin at March 16, 2008 11:19 AM
My parents installed an inside French drain to their house, and the basement walls were always damp or wet. I now know that the correct way to fix basement water is from the OUTSIDE after doing extensive research on this topic. This type of fix is called an exterior french drain, or sometimes an exterior foundation drain and is foolproof.
Posted by: guest at March 16, 2008 6:11 PM
of course the broker swore it would work! She wants to collect the fat commission. What does the broker know about construction?
All of the above are good points. I am about to fix a foundation crack, structural, we are replacing the wall in the house we just bought. Guess what the sellers broker said, Oh the owner said that crack has always been there! Great, we'll just take her word on it and hope the wall doesn't collapse!
We are putting in the exterior foundation drains on three sides of the house and connect it to a catch basin. (this is a detached, suburban house)
Go in a rain storm and see where the water is coming in. In my old brownstone we got water in the basement. The problems: a clogged storm drain in the back garden and the neighbors had new gutters installed but did not have their sewer line cleared out. When it would rain, their gutter would back up and then flow into my yard like a river. Several compliants later, they cleaned out their drain. In addition to the fix in my yard, no more water in basement. It was a couple hundred dollar fix, verses several to tens of thousand fix.
Posted by: guest at March 16, 2008 8:17 PM
I believe the broker was talking about an exterior French drain. Yes, I know I have to be wary of a broker's advice, though he is also someone who owns several properties so I thought it was worth researching his suggestion further.
So if we do an exterior French drain, what is a ballpark cost to have in mind for a bldg that is 16.5 x 40? And if you do an exterior one, does that rule out the need to do an interior one in addition? If there are vendors people can recommend to get ballpark estimates, that would be helpful too. The broker recommended Vulcan - anyone use them?
Again, suggestions greatly appreciated. Thanks!
Posted by: housesearcher at March 16, 2008 11:24 PM
I can't speak on my price as it is in the suburbs so is probably not relavant to brooklyn. Plus my house is surround by dirt so it will be easier to excavate. My guy says that once we will do the exterior drain work it should solve the water problem. So no need for an interior drain. However we have a wall at the front of our house that we are not waterproofing since it is covered by a front porch and part of the roof line. He thinks we can handle the water with waterproofing the sides of the house and if need be do a french drain on the interior for the front wall that hooks into the drain system.
You can email at thirdstapt@aol.com if you have any more questions.
I can't stress enough about checking yours and your neighbors gutters though!
Posted by: guest at March 17, 2008 12:35 PM
Don't feel dumb, Bob, that's the way to do it, bit by bit to figure out the problem. Each time it rains people should observe where the water is coming in. Even go outside in the rain and look where it's pooling up and where it's coming from. It's seldom fixed all in one step.
Those "waterproofing" companies who come in and install french drains and put waterproofing coating on foundation walls are not figuring out the real problem and source of the water.
Posted by: guest at March 18, 2008 1:12 PM
Some waterproofing companies do. My problem is I have cinder block walls with no waterproofing at all. On some parts of the basement where there is no dirt, you can see thru the wall!
I also mentioned above how important it was to check your gutters and neighbors.
I live above the Hudson and below a mountain. The water is coming from the sky and the ground!
We are waterproofing the outside by installing an ourdoor french drain, which will go into a holding tank to drain out slowly. Our gutters will hook into this. It won't be a situation of painting every thing with thorocoat.
Posted by: guest at March 19, 2008 10:44 PM
You will want an experienced engineer to design any exterior french drain or you can have more problems than when you started.
Underground water flows are tricky and need to be designed correctly in order to work right.
Posted by: guest at March 23, 2008 9:44 PM
Post a comment
Please be patient while your comment is published. It may take a moment.