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clogged french drains??

Posted by vamom3 (My Page) on
Mon, Feb 4, 08 at 11:42

Hi,
I was wondering if anyone has had any experience with this situation:
We have lived in our 1954 house for 5 years. In the early 1990s the previous owner had a well known basement waterproofing company install a sump pump and french drains around the perimeter of the 1400 squ. ft. basement. It has rigid plastic sheeting around the perimeter that extends up 2 ft from the concrete floor.
The first year after we moved in , my husband drylocked the cement blocks. The basement is not finished.

The first 3 years we had no water issues, even through Hurricane Isabel! In the last year and a half we noticed creeping mildew and bought a de-humidifier. The problem has gotten continually worse until this fall we had an actual leak in a portion of the front wall. The original company came out, installed a larger piece of sheeting and called it fixed. In the meantime we have had water 2 more times, including last week when it came from another section of that same wall. I called a 2nd company that was well recommended and they said:

You need a 2nd sump pump for your squ.footage, and the original company used pvc piping for drainage and they are most likely clogged with silt and clay soil.

If anyone has any experience with a failure of a waterproofing system, please enlighten me! At this point we would like to tear it up and start over although the cost isn't pretty! Thanks!!


Follow-Up Postings:

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RE: clogged french drains??

The drain under the floor should be set in gravel. A geotextile filter fabric should be used between the native soil and the gravel to keep the fine soil from clogging the gravel and the drain.

An exterior french drain system is superior to an interior system.

If you are re-doing the french drain anyway, have them install clean-outs so that if it happens again, you can have it cleaned out.


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RE: clogged french drains??

Thanks for the info!
Scott52, we are located in Northern Virginia.

Brewbeer, I do think the piping is set in gravel. The filter fabric will be a good thing to ask about. Apparently, the system right now is solid pvc which was standard for this company in 1992 when it was installed. The 2nd company I called uses corregated 6 inch tubing with slits to allow for silt to filter out.
Isn't an exterior system out of the question for an older house that already has moisture throughout the old cement block?
I had never heard of clean-outs. I will ask company #2 and others that we will probably call before we make the investment to rip out the old and start again

Thank you for the helpful responses!


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RE: clogged french drains??

An interior system doesn't do anything to keep water out. The only time you're forced to it around here is where there is no access. For instance, in, downtown homes, which are frequently built 1-3 feet away from each other.

From the outside, I'd put in weepers covered by geotextile fabric, then covered by at least two feet of non-packing gravel connected to either municipal drains or an inside sump pump (depending on local regulations). For the wall, I'd combine: 1) a flexible barrier, either a spray-on waterproofing, not dampproofing or combination fabric/fibrated asphalt or similar systems, followed by 2) a properly installed plastic membrane such as Delta. Then backfill with a freeflowing material, such as sand, followed by a clay cap. This will protect you from everything except water rising through cold joints at the floor because of a high water table.


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RE: clogged french drains??

Thanks for the input!
Worthy, If I am located 2 blocks from the Potomac River in a "swampy" area, does that mean I am most likely in an area with a high water table?
Most homes in the area seam to have a similiar system as the one we have now, could the water table be the reason?
Thanks for the detailed info!


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RE: clogged french drains??

There are a lot of wetlands in the Potomac watershed. So occasional water in the basement is not surprising. But since the water is coming from one area, exterior waterproofing would likely handle it. If you get it done, be sure the contractor pays special attention to the joint between the wall and the footings. There are a number of products designed for that.

Many waterproofing contractors use only the second part of the two-element system I described above. But since the biggest cost is the excavation, it's worth going the extra mile. Many basements are only four-five feet below grade anyway, so there may not be that much extra cost involved.

I built a home last year two blocks from Lake Ontario that required a 10' deep excavation. We were above the water table, but there was a constant flow.


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RE: clogged french drains??

That's a nice set of photos showing the steps I mentioned. They even include the free-flowing backfill, an essential step that most everybody chintzes on. I should add that if you use gravel free-flowing fill, it's good to lay a geotextile on top to keep soil from clogging the fill, then cap it with clay, then topsoil if you want plants on top.


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RE: clogged french drains??

Worthy, Thanks. Good advice.


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RE: clogged french drains??

Thanks for all the detailed advice. We had another steady rain day this week and water continues to be a problem.
The specific details are extremely helpful and give us an opportunity to "appear" somewhat knowledgeable when we contact the waterproofing companies.
One of the issues we have with the original company is that apparently the company was sold and is now franchised(Work was done in 1992) When they came to repair, I was sent 2 young and not very professional guys that seemed to not have much knowledge about potential causes, and simply patched by nailing up a larger piece of this plastic sheeting.
We do want to conserve our cash because you always have something to repair but I feel much more comfortable with company #2 found on Angie's List. They came out twice and sent 2 (estimator & site supervisor) to evaluate the issue. They of course suggested trying to get #1 to fix first.
If you recommend external excavation, would this be effective even in an old house where water has obviously leeched through the cement brick for 50+ years?
At some point we would like to develop some of the 1300 square ft. down there!
Thanks once again-


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RE: clogged french drains??

Let this be a lesson to all of you. A "lifetime warranty" is only as good as the life of the company. A PROPERLY installed interior system will work perfectly. Do a Google search on any prospective contractor. There are many good companies in Northern VA. Exterior excavation is a primitive and intrusive way of waterproofing a basement. The satisfied customers of an interior system are reaching numbers into one million. Exterior repairs are in the thousands. The proof is in the puddin'. If the original company is refusing to stand by their warranty, then hire a reputable company to come in and redo it. Don't try to "cheap" this thing. Your basement is a valuable part of your home.


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RE: clogged french drains??

WTRPRFR says it best. Interior french drains collect water that has already gone under the footing of the basement and then get pumped out. But why collect the water after it is already slowly eating your footing away. Also interior drains do not deal with any cracks issues in your walls. Unless you have very close quarters the exterior french drain is the way to go. It collects the water before entering from under your slab in your basement. I never liked interior drains. They are a waste of money. Bought a 1920 house with just a sump pump and no interior drains. Sump pump gets the water out just as well, without interior drains. Unless your soil under the foundation doesn't transfer water to the sump pump. Excavated about 5 feet deep around the entire house and added a exterior french drain after I repaired cracks and waterproofed the exterior side. Added clean outs on my drain. My wife and I never want to hand shovel about 5' deep, 18" wide, and about 150' of dirt ever again. But no water. And got a renter living down there now. Interior drains are like walking into the house with muddy boots. But why do that when you can take them off outside.lmao


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RE: clogged french drains??

Where you can find specific cracks admitting or likely to admit water, polyurethane or epoxy injections are the obvious first approach.

Photobucket
Epoxy Injection into settlement cracks in a new home Photo: Heather Joy Investments Ltd.


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