Wet basement: sump or french drains?


Old 03-12-11, 06:49 AM
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Wet basement: sump or french drains?

With all the rain and snowmelt recently I got a good amount of water in my basement -- seepage where the foundations walls meet the floor. However, in 4 years in this house, and some pretty seriously wet springs in the past, this is the first time I've gotten water. However, I'd rather not worry about it and I would like to address it.

The property is poorly graded for this purpose: the house faces north, and the east and southeast side of the property slopes pretty sharply towards the house, while the west side slopes away (and much of the foundation on this side is above grade due to the slope). The east side is mostly granite so further grading is not really an option.

Gutters and downspouts are good and splashblocks direct water away from the foundation.

So am I thinking about either french drains or a sump. I haven't gotten any quotes yet but I'm assuming the french drains will be more expensive. Any sump would have to be a local sump (no perimeter drain tiles) for budget reasons.

Is one of these options preferable to the other? Any other options I should be considering?
Old 03-12-11, 07:03 AM
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Trackstar - I fought a wet basement for several years before getting it manageable.
The first thing I would do is extend the gutters out further away from the house. My downspouts feed buried drain pipes that carry the water well away from the foundation. One feeds a dry well and another is routed to a low spot about 80' away from the foundation.
For a couple of years I would unroll a drain line from the downspout whenever a heavy rain was predicted. That worked but was a PITA. I finally buried it. That helped in all but the wettest situations.

Then I installed interior perimeter drain pipes and a sump pump. I did the work myself after finding out how expensive it would be to have french drains installed. The cost of materials, tool rentals etc was just a few hundred dollars (15 years ago) including the sump,pump and a new dedicated circuit.
Old 03-12-11, 09:14 AM
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Darn the luck, we are all the same. We don't want to take the time or spend the money so we manage to kid ourselves into omitting a task. The facts are if we did this (install tile perimeter and sump) back when we popped the forms off the newly poured footing it would have hardly been an expense at all. Not just about you at all trackstar just human nature. Now it's time to anti up and pay the fiddler. It costs much more now.

Sounds like you are looking for a cheap fix with a French Drain and a sump. I will start with one very important point. You mentioned this is the first time the basement has flooded. It will not be the last. But the water is entering the cold joint between floor and footing I suspect. That sump you are thinking about as well as any beneficial tile run leading to the sump will have to be very deep to be effective. It is going to have to be below the floor level to be effective.

Now you say you have have got grade higher than your framing to deal with. Do you happen to have any side of the house leading to lower grade that you could pipe the ground water to allow the water to drain away? If you do might it be lower than the basement floor? If so, you might not need a sump or pump.

Old 03-20-11, 10:31 AM
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once leaking water begins, its not likely to ' heal ' itself grading & downspout work will obviously be a boon to resolving the leaks as will a properly designed/installed sub-floor interior perimeter drainage system leading to an integrated sump & discharge pump
Old 03-23-11, 02:16 PM
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Below is a list of grading basics:

* If your basement is 4 or more feet below ground no amount of grading will make a greater than 40% difference on any water appearing in your basement.
* Adding dirt to the side of your house is not grading. Doing this only adds to the overall depth of your basement (not a good thing).
* Grading is not adding dirt to the side of the house but removing dirt further away from the house thereby creating a natural downward slope. This often requires the removal of many a load of dirt.
* A grade of 15+% is desired. Basic required slope length would be a minimum of 8 times the depth of the basement. For instance: If you basement is 2 feet below ground the slope would need to be at a minimum of 15% and a minimum of 16 feet long. If you basement is 6 feet below ground the slope would have to be a minimum of 48 feet long.
* Piling mulch up against a house will not cause water to run away from the foundation. (See first two points).

all true. Taken from ****** they have good images and straight talk about basement leaks.

Last edited by Shadeladie; 03-24-11 at 11:08 AM. Reason: Link removed
Old 03-25-11, 05:34 AM
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I have to disagree with cline. First, a 15% grade is a 3-foot drop in 20 horizontal feet. The highway from Eisenhower Tunnel from the Rockies down to Denver is a 7% grade. Wheelchair ramps run 5-6% grade, legally maxxing out at about 8%. A 15% grade is a "kill grandpa" grade.
And grading makes a huge difference for basements, but it's not good enough just to pile dirt up against the foundation, if you have a pond 20 feet from the house. Ideally, you have to provide a runoff path so that your yard drains to a point below the level of your basement floor. And this may require carrying the runoff around your house, from the high side of the yard to the low side of the yard and beyond, the way it would run off if there were no house there, and no hollow spots. Slight, gradual trench-like depressions (swales) that split the stream above the house and divert it around the house and away from it are all that are required. If you've got decent soil, they don't have to be noticeable as "trenches," but look like contours of the lawn.

That said, a sump pump is a lot cheaper than french drains, and if it doesn't work to your satisfaction, you won't be broke from trying it. Just find the low point of your basement floor and pop a hole in the slab. A concrete septic-tank cleanout-sleeve is good for the liner, because it's about 18" inside diameter and about 2' long, and has a little recess along the inside of the top edge that can be used to support a cover/grate made from spaced 2x4s (pressure-treated). Dig slowly near the bottom of the hole so you can set the liner on undisturbed soil with its top flush to your basement floor. Grout the gap around the edge of the hole with concrete, and dump some in the bottom to finish the sump, and install the pump.
Old 03-25-11, 06:54 AM
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I've been going through a similar flooding ordeal which has worsened over the years with water entering through the cold joint. When this house was built in 1971, perimeter tile was installed around the outside of the foundation. Apparently, it has failed, for some reason, and investigating that isn't an option since some of it runs from the front to the back of the house and would require major destruction to access. I recently had a product called [I]Xypex[I] applied. You might like to check out their website. I can't attest to it's effectiveness yet, since weather conditions haven't triggered a good test, but it has a great reputation. Good luck!

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