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Weepy walls = sad homeowners.
December 5, 2012 7:05 AM   Subscribe

Basement drainage issues...suggestions?

I've got a 100 year old brick home with a full (mostly unfinished) basement. It was designed to take water on its rear wall, and it does so quite well. However, seeing as how we're 100 years later, "drain it to the street" isn't a great option any more for a bunch of reasons.

Anyway, the water used to weep in that wall, flow all the way across the floor to a floor drain where it meets the public storm drain system about 30 feet away (and 10 feet down). That pipe is crushed AND the city tied it into their new system in a dumb way (beneath the new line, like it comes in beneath it), and so that drain doesn't work. Also, it takes my washing machine effluent water, and we really shouldn't be dumping that to storm sewer, even if I DO use environmentally friendly detergent.

Over a year ago I installed a large sump @ the rear wall, and it works perfectly. No more water on the main part of the floor. It drains to the main stand line. It's way oversized, something like 4000gph, it runs about 20 seconds at a time about once an hour 24x7, much more often when it's actively raining. It's definitely draining under the pad, which is great, as I haven't had any more water up through the floor in the last year. (In case you're wondering, once I get the floor dry back there, the washer will move to drain into the sump.)

The problem is that nearly the entire back wall weeps, from as high up as 2-3 feet off the floor when there's a lot of water to just seeping in at the plate at the bottom. This is a monolithic foundation, the basement floor is NOT part of the footer, the foundation walls are solid sandstone with limestone-based grout. This weep gives me an area about 6-8 inches wide that stays wet pretty much all the time, making it GROSS. It also leads to mildew in the basement. A 70 Quart dehumidifer running 24x7 can't make it less than 55% humid down there, even when it hasn't rained for days. Add to that that my fiancee is extremely allergic to mildew, so she basically can't go in the basement.

I'm addressing my downspouts and the direction of that flow, but even when that is addressed, we will still have seepage on the back wall.

I have all the tools to do anything myself, but I do NOT have the funds to do something like excavate the exterior foundation and reseal, that will NOT happen so PLEASE don't suggest it.

I'm thinking I should drill weep-holes and install some sort of drainage tile, although I'd prefer to avoid tearing up and repouring the floor, even though I DO have the demo hammer to do it if necessary. (I have weep above the floor, I feel like drainage tile w/o holes won't obviate that problem.) I found a sort-of baseboard material where you drill holes and then place the baseboard over the holes, giving the water a way to flow w/o coming out onto the main floor area, but I can't seem to find such a system that isn't intensely expensive.

I use the basement as a workshop and my dogs spend the days down there. It will never be 100% finished space in my lifetime (6' ceiling, ductwork, stone walls, etc.), but it would be nice to store stuff down there without having to un-mildew it before use.

So, TL;DR-
Need a way to deal with weeping water from one basement wall. Sump pump in place. Cheap is ideal.
posted by TomMelee to Home & Garden (9 answers total) 3 users marked this as a favorite
Not quite clear: your city has both storm sewers and waste sewers, right? So which one does the sump drain into?

In any case, the real solution has to be to stop the water from coming into the basement, period. The mildew is not healthy; that musty air is probably circulating into the rest of your house; the moisture is not good for the first floor joist structure, etc. With the sump and dehumidifier you're already doing everything possible to remove water but the end result (55% humidity and grossness) is not acceptable. Weepholes and drainage tile won't alter the fact that water comes in through the wall and evaporates into the basement air.

The solution is outside. You know what you really need to do, but you don't want that suggestion, so I won't make it. So short of that your best options would be: (a) redirect your downspouts, (b) install a french drain some distance out that directs water around the house (can be done without contractors, just a lot of hand digging), (c) regrade back there so terrain slopes away from the house toward the french drain. If there is not a lot of underground water migration, that might take care of the majority of the seepage, but it won't stop the problem.
posted by beagle at 7:22 AM on December 5, 2012

Thanks beagle.

I'll try to answer and respond as best I can:

We have storm sewers and waste sewers, both are ancient and barely working. The sump is currently draining to waste sewer (which I recognize isn't the best option, but it's the only option, and we're not charged by outgoing volume.)

Part of the challenge here is that we're in the midst of the Ohio River Valley here, there is tons of water EVERYWHERE. (When I dug up my front drain to the street, in 8 vertical feet of excavation I uncovered about 5 active springs. 5. Active.) Additionally, my back yard slopes downward into the house. Granted that it should have a swail, 100 years ago they didn't worry about such things. The challenge is that no matter what I do at the surface, there will ALWAYS be water against that wall. Seriously every house in this town has this same problem, heh.

I am working on downspouts. My challenge with french drains is that I don't appear to have water at the SURFACE. Like, where it leaks worst is always dry at the ground. That means I've got underground issues, blah. Adding to all this is the Nazi neighbor I've spoken about here before, who will make my life a living nightmare if I do anything visible outside. (I'm saying he called code enforcement every day for 40 days because my mower was set on 3.5 and not 2.5). My rear-basement floor is something like 10 feet below grade as well, so excavation is going to be a BFD.

Oh, and lastly, I have no near-surface tie into the storm system, just the 8 foot underground T that's beneath the main line (seriously it pushes water up into my basement, bad news.), just an under-sidewalk-to-street line, which is fine but that's a helluva lot of water to dump in the street.
posted by TomMelee at 7:48 AM on December 5, 2012

So pumping the weep water into the waste sewer is probably some kind of violation; be prepared to deal with that issue sooner or later.

If you were building a new house in that location, it would have a nice waterproofed foundation and drains all around, and your basement would be cork dry. Regardless of how much water is out there, that condition is achievable at a cost (short of jacking up the house and building a new foundation, you know what's necessary, it's the answer you don't want supplied here).

So, short of that, let me make one other suggestion: install the weepholes drain tile you're thinking about, creating a clean flow to the sump. Then, build a reasonably water-tight wall in front of that, all the way across the back wall, let's say 3 feet out, with a door for access. It could be studs with heavy black plastic stapled to it. And black plastic on the ceiling in there. Seal it up as tight as you can, including weatherstripping the door. Install the de-humidifier in that space. Basically, now you have confined your water problem to a narrow space at the back of your basement, and the rest of the basement (and house) should be much more dry.
posted by beagle at 8:18 AM on December 5, 2012 [2 favorites]

I think beagles idea of isolating the wet wall from the rest of the basement is pretty good. It's easy and cheap to implement. (I may just try it out for my similarly damp, stone walled basement)

You may also want to look into other dehumidifiers, as the current one may be undersized, especially if it is running constantly.

This website is a terrific resource for all sorts of building issues and could have some ideas...

A lot of it is for new construction, but they have a fair amount of info for retrofitting solutions.
posted by orme at 9:09 AM on December 5, 2012

Is there any way to get surface water away from the wall? We had a (much newer) home that was leaking/weeping through the wall. The downspout on that side of the house was plugged and water just cascaded over the gutter and onto the ground and pooled near the basement wall. I fixed the problem by putting a new downspout in. There was a drain for the downspout that went down to the footing, and once I got the water there directly without pooling on the surface, my leaking wall stopped leaking.
posted by Doohickie at 9:11 AM on December 5, 2012

So it turns out one of my good friends is a code enforcement officer for my small town. That doesn't mean he wouldn't give me a ticket---he's pretty upstanding like that, but he was over looking at my yard with me the other day and I showed him where the water goes, and he says it's not a problem (because everyone who has a sump does the same thing.)

I like the false-wall idea. That's probably more do-able and the dehumidifier wouldn't need to run very often. It'll also give me an easy way to put more outlets on that wall. Once my neighbor dies and if we're still here, I'll excavate and do it 100%. I'm working on a home inspector license and probably a GC as well, although it'll just be for expertise, I won't run a business.

With the weep-holes, won't they just plug up eventually with sediment? Is there like a screened pipe or something? How big do you think? 1"? Spacing? Height?

Orme-We bought a top-of-the-line, ultra efficient 70 Quart dehumidifer and it almost doubled my electric bill. Then I plugged in a second one and it went up an additional 30% and neither of them ever shut off. Granted, that was in the super duper damp spring time, but that's just a silly bunch of wasted electricity that we can't really afford.

Doohickie--There isn't surface water, that's the weird thing. I will be excavating my downspout lines in the spring.
posted by TomMelee at 9:23 AM on December 5, 2012

With the weep-holes, won't they just plug up eventually with sediment?
Could be, but you could just re-drill every now and then. Screened pipes won't do much good unless you can have a cavity, outside, around the pipe, filled with stones and lined with landscape fabric, like a mini french drain. But you'd have to dig outside to do that, in which case you might as well do the unmentionable proper repair job. So I would just drill holes, stick in a little course plastic wool (like a sink scrubber) to keep the soil out, and redrill as needed. If you want to stick pipes in, I'd make it half-inch, and then hook up a network of flexible plastic tubing with connectors that all drain into the sump. With a little caulk and luck, you might get most of the water to come in that way with much less on the floor and seeping down the wall.
posted by beagle at 9:44 AM on December 5, 2012

Cool. thanks. This solution should work pretty well.
posted by TomMelee at 9:53 AM on December 5, 2012

Where is the water coming from? Are you in an area with a high water table? Or are you downhill of an underground spring? If you're in a high water table area then you won't have a lot of options. But if not then you really need to get a handle on where that water is coming from and perhaps set up a way to redirect it away from your foundation.

Are there neighboring houses that have similar issues? If so, what've they done about it?

My first thought would be to dig a bit of a trench a few feet away from the outside of the foundation and check the soil condition and water level. If you're seeing water farther away then you might be able to set up a french drain out there to catch and redirect the water before it gets to the house.

What may have been working for "100 years" may no longer be effective or outside conditions have changed, making it unable to keep up.

Nobody likes the idea of having to excavate their foundation exterior walls but water damage does not get cheaper over time.
posted by wkearney99 at 7:52 PM on December 9, 2012

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