Water Infiltration Remediation

Old 08-11-03, 10:05 AM
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Unhappy Water Infiltration Remediation

Water is seeping through the basement wall of my 65 year old home. The foundation is poured concrete to a height of about 4 feet with double course brick above that. Can actually see water leaking through wall at points along the concrete/brick joint during periods of heavy rain. Suspect that it is also leaking through the wall/floor joint and possibly other weak points in the concrete foundation wall. Above the concrete/brick joint seems to be okay.

Anyway, got a proposal for remediation which, in brief, is as follows:

1. Install interior water management system (98 linear feet) including:
- one heavy duty submersible sump pump (1/3 HP Zoeller);
- one battery-operated (backup) sump pump system;
- one clean out; and
- one Humivent.

2. To install this system they would:
- open perimter of floor out from wall;
- remove the existing concrete to expose footer;
- install mechanical spacers for support (5/8" rebar);
- create a trench around the perimeter of basement approx 8"-
10" deep and 6" wide from edge of the footer;
- line the trench with filter fabric;
- install sump pump;
- place 3/4" clean stone and 4" perforated ADS pipe (graded 1"
- per 10 ft);
- drill drainage holes in Keyway at base of concrete foundation
- install plastic drainage board against wall and across footer;
- place additional 3/4" clean stone over 4" piping;
- place 6 mil polyethylene vapor barrier over trench; and
- hand trowel cement to close trench.

3. They would also cover the walls with interlocking "wall board" (not dry wall, but an impervious material that is approx 1/4" thick) to allow any water that penetrates the mortar joints in the brick to be directed down the internal surface of the wall board into the drainage system.

4. They would then apply "Anabac" mold detergent and mold shield to the basement walls. (I recently found mold growing in some areas where water infiltration is worse.)

5. Finally, they would install the Humivent (which vents to the outside, not to a dehumidifier) to dehumidy the entire basement.

6. Alll walls, floor and cove area are under warranty for as long as we own house (and is transferrable upon sale). Will not warranty walls without wall board system (which represents about $3,100 of total cost).

Total cost for the above is about $16,500.

I am in NYC area. Seems expensive for what basically sounds like a French drain system (though the contractor emphatically stated that it is not a French drain.) Does this sound like the best was to go? Any advice/comments/suggestions before I take the plunge?

Thanks in advance for your help!
Old 08-11-03, 10:34 AM
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Do you have gutters? Are they kept clean? Are they functioning correctly? Do they collect ALL the water that comes from the roof in a heavy rain, including valleys?

Do you have downspouts? Do the downspouts have leader pipes at the bottom that carrys the water at least 6 feet away from the house foundation?

Is the ground surface around the perimeter of your house graded properly, such that the ground slopes away from your foundation, in all directions, for at least ten feet?

If you answered "no" to any of these questions, then these areas should be addressed before you drop 16K on the other recommended fix.
Old 08-11-03, 12:44 PM
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I have a flat roof which drains through a scupper in the parapet wall to a downspout which which discharges through an extension that is five or six feet away from the foundation wall. So that is not the problem. Part of the problem is that my house is on a slope and when the ground becomes saturated with water (after heavy or prolonged rain), groundwater traveling down slope runs into the north/east walls of my foundation. The hydrostatic pressure created by this condition causes the water to infiltrate weak spots in the foundation wall and seep into the basement. So I think that while your suggestions certainly make sense they are not the cause of my particular problem.
Old 08-11-03, 12:57 PM
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Can you intercept the water before it gets to the foundation? A French drain with a bottom well below grade running to daylight could catch the water before it gets to the foundation. Three feet wide and 6-8 feet deep filled with gravel and protected by barrier cloth. Drain line at the bottom running to a lower location. If you really need it a pump could be used, but daylight is cheaper and gravity is always 'on'. No matter what you do with a cove type system, the basement is wet. It may be in a better place than running on the floor, but it will always be damp. The concrete floor alone will transport it.
Old 08-11-03, 01:28 PM
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Brickeye is correct. ANY solution that intercepts the water flowing overland during heavy rains before it gets to your house foundation is ten times better than collecting the water inside the basement and then discharging it.

Can you re-grade the north and east side yards to deflect water from around the house?

Does your downspout discharge to the north or east side of the house?
Old 08-12-03, 07:41 AM
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The problem is that, at its narrowest point, the north side of the house is only about four feet away from the neighboring property line. Thus, I cannot get a backhoe in there to dig out a trench of the size you suggest for the french drain.

The ground on the north side is also covered with concrete right up to the exterior brick wall of the house. Thus, I'd have to rip out all of the concrete if I wanted to regrade that side of the house. Regrading might also create another problem. Because the bottoms of the basement windows are now about even with the top of the concrete sidewalk, the regraded earth might end up being higher than the basement windows!

The downspout from the roof discharges to the south (downgradient side) of the house, and so I don't think that is a problem.

I did see an article in which a guy put in a "linear french drain" which was only 24 " deep and 6" wide. Do you think that would do the trick?

I definitely see the advantages of taking care of the problem from the outside rather that dealing with after it gets inside the house. I'm just not sure if and how it can be done.

One more thing. Has anyone heard of a system in which some type of liquid is injected into the ground around the exterior foundation walls through pipes, which then hardens into a solid mass thus creating an impervious water barrier around the foundation? This sounded like a good idea to me, but I can't seem to find out who does this kind of basement waterproofing.
Old 08-13-03, 05:58 AM
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The shallow french drains are more effective against surface water. Does the wall leak all the time? or after a heavy rain? right away during/after the rain? or does it take a while to start? Fixes depend on how the water is moving. If it leaks during/right away the problem is probably more surface water and even a shallow french drain might intercept it. If the leak shows up after a while you may need to get deeper. If it is all the time, deeper still. The best way to fix leaks like this still is from the outside. Divert it away, and install a first class barrier on the outside of the foundation to try and keep whatever gets by out.
Is the concrete pad sloped away from the house? Is the joint against the foundation really well sealed?
Old 08-13-03, 09:28 PM
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I know your pain with the wet basement. I recently bought a house with a wet basement (it was 'dry' in the disclosures...I've been advised to sue -- don't want to). I've reduced my water problems bigtime by having done what is being described here.

When you mentioned your basement windows, can you create a window well? This will create a barrier to hold back the dirt for your grading (I installed 4 on my house for my grading project).

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