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Basement door drain clogged
12 January 2008


Q. We have a two-story house with a basement built in 1980. The problem is whenever we get substantial rainfall, the outside cellar drain, located at the bottom of the stairwell by the basement door, fails to work. Water then collects and once it reache s the bottom of the basement door, a distance of about three inches, water begins to seep inside causing the basement to flood. I called a company that supposedly specializes in drain problems. The person they sent out to look at the drain told me that w hen my house was built outdoor drains essentially emptied into a series of gravel filled tunnels under the house. He said that since there was no drain pipe, there wasn't any sort of structure he could clean. He said that over time silt collects and the drain stops working. He also said that there was little if anything I could do since any type of work would require cracking the concrete stairwell and the basement foundation to run a new drain, which would be extremely expensive. He suggested covering the outside stairwell with a tarp. I think that water also seeps from the surrounding ground into the stairwell so I doubt that covering the area would solve the problem. I also find it hard to believe that there is nothing short of ripping up the found ation that I can do to prevent my basement from flooding each heavy rain. I've purchased a portable sump pump, but if I'm not home when it rains, then I'm out of luck. What options do I have? I'd certainly appreciate any advice you may have.

A. I donít believe the contractor who came out and looked at your areaway-- thatís what that basement exterior stairs and entry are called-- wanted to get his hands dirty. He was correct in telling you that the drain there is silted shut and thatís part of the problem. He probably wasnít alive in 1980 or if he was he wasnít in the business of installing areaway drains at the time-- I was so I can tell you how it was done.

After the foundation walls were put up and before the basement concrete floor slab was poured, a perimeter trench was dug inside of the foundation walls all around the basement that ended in a sump pit. The drain was normally perforated flexible plastic pipe--three or four inches in diameter--placed in a bed of gravel. Then gravel was spread over the earth of the basement floor to a thickness optimally three to four inches deep. A sheet of thick plastic vapor barrier was placed over the stone and the fl oor slab was poured. Any areaway had a bell-trap drain installed which connected normally with a two inch plastic (solid) pipe that dumped into the perforated pipe just about a foot and a half inside of the door under the slab. Bell-trap drains are used because they have a small perimeter trap that ostensibly intercepts silt before it gets into the drain pipe and clogs it but we both know it doesnít take much to clog that drain.

What the fellow described as the drainage system that he thought was there was a variation of the French drain theme that was sometimes used- mostly unsuccessful in the long run-- before the system I described was set in place via the building code.

It could be that the silt that has clogged your areaway drain pipe over the last 28 years is as hard as a rock and will not yield to snaking or flushing with a high-pressure hose--but Iíd try that first. Thatís where getting dirty comes in. If that fails then he was right to a degree about breaking up concrete. Youíd need to cut a channel from the areaway drain into the basement inside the door to locate that perimeter drain and install a new drain line. Itís not wholesale demolition and you could do it yourself with a rented rotary-hammer that will make breaking concrete relatively easy.

I see areaways covered with both permanent or makeshift covers that tell me right away the drain is prone to clogging. Controlling water sources getting into the areaway stairs should start with the gutters directly over head and the grade outside of the areaway wall itself. I have seen folks so frustrated that they have dug and installed a dedicated sump pit and pump at the base of the areaway steps. Others will erect a shed roof structure to prevent any rain from falling on the steps. Extreme but it w orks.

When you finally get the drain clear set a water permeable entry mat over the drain so the it intercepts the silt before it gets to the drain and wonít let only a handful of leaves clog up the works.

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