Fun With Foundation Drains

My house was built in 1939.  I have it on good authority – an old man who lived in this neighborhood 27 years ago when we first moved in – that the house was built by an engineer for Union Carbide.  That company is now defunct, but was once a multi-national corporation that led the world in the production of insecticides, plastics and polymers.  There are lots of reasons to believe an engineer built this place.  It is solid construction, true masonry, cherry trim and nice plaster work with extraordinary attention to detail obvious here and there.

But it is old and it’s age is starting to show.  Our basement is not finished, but we do store stuff down there and that’s where I keep my tools and where we have our washer and dryer.  In the last few years, we’ve started to get a little water in the basement when the rainfall is unusually heavy.  We stay dry in and after a light or moderate rain, but if we get a gully-washer, or one good rain right after another, we’ll get streaks of water across the floor here and there, always in the same places.

Like any jack-leg homeowner who is not an engineer, I made stabs at ameliorating this mild and non-urgent problem.  I hired a crew to dig a ditch two or three feet above the corner of the worst leak and put in a french drain.  You know, perforated pipe covered with pea gravel and a fiber membrane.

That made no difference at all.  And so, I let the matter go for a few more years.  It was really nothing more than a cosmetic problem, I thought, and nothing to spend a bunch of money on.

Later, I dug down a ways, just outside the spot of the worst and most clearly-defined leak.  I found a rupture in a tile-line there that I was sure was causing the problem.  I fixed the rupture and felt satisfied with myself until the next hard rain made it clear that that rupture was not the cause of the leak.  Again, I ignored the problem for a long time.

Once again, I was motivated to take care of this issue and this time I dug in the same spot, but deeper.  I found another line of four-inch clay tile, just at the base of the foundation.  It was kind of odd-looking, I thought, since the tiles were not joined or connected in any way, but just laid end-to-end.  I figured – wrongly – that this line of tile was simply the older gutter-drain and that the one above it had been installed to correct some problem in the mid-20th century.  I could not imagine why anyone would install pipe that way – just laid end to end, with no sealed joints.

I later learned – by watching Youtube videos about foundation drains and later talking to my 86-year-old father who used to build houses – that this line of pipe was actually the foundation drain and the end-to-end, no-seal business was exactly the way they did things back in 1939.  The gaps – just thin lines, really – between the lengths of pipe were what let the rainwater into the drain line.  Didn’t sound like a great idea to me, but, then again, it had worked to keep my basement dry from 1939 until about 2009 and, you know, seventy years ain’t bad in this context.

What I learned from the video was that these “field-tile drains” so configured, also allow a little silt to come into the pipe with every hard rain and thus, over time, they fill up with soil and, finally, cease to function.  Then, water in the basement.

I pulled one length of this tile from the line and it was almost completely filled with soil.  It was only about a foot long, but it weighed a ton.  The hole I was working from was near the end of that drain line, so I set about to clear out the past few feet of it.  I just took out the last tile – also completely occluded – and then used garden-hose spray and a metal rod to ream out the line up to the hole I had dug about four feet up the line.  The work went a little faster than I had expected.  The pipes were pretty full, and the sediment had been set there for a long time, but it consisted of the finest silt – no rocks or any kind of conglomerate – and so it was more susceptible to dissolution than otherwise.  Still, it has been awkward and very slow work.

A day or so later I bought a special fitting for my garden hose that gave me a stronger stream and  I have introduced laundry detergent into the water stream in the hope that it will help chemically to dissolve the years of sediment.  To date, after digging and working from two more holes down to the drain at places up and down the line, I have flushed maybe twenty-five feet of the old line clear of all sediment.   This leaves me with at least another twenty-five feet of line to go and there will be no way to determine success until all of it is clear so that the water flow does not stop and leak out anywhere along the way.  I think I still have the toughest part of the job ahead of me, but the progress I have made is encouraging and the prospect of actually solving the problem without spending the estimated $40,000 to hire a crew to dig the whole foundation out and install a new line is a great motivation for me.

I have a few videos of my work that I will upload and I will keep you apprised of my progress as I continue my efforts.


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