"Basement door drain clogs and leaks"
Column #807 08/07/10
On The Level
Q. We have a older two-story house with a basement that was built in 1973. The problem is that whenever we get heavy rain the outside basement drain located at the bottom of the stairwell by the basement door doesn't drain. Water then collects and once it reaches the bottom of the basement door water begins to seep inside causing the basement to flood. I called a company that supposedly specializes in basement water problems.
The person they sent out to look at the drain told me that when my house was built floor drains essentially emptied into a series of gravel filled tunnels under the basement slab. 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 foundation 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 I'm out of luck. What options do I have?
A. I don't believe the fellow who came out and looked at your areaway, that's 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 that's part of the problem. He probably wasn't even born when your house was built or if he was he wasn't 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 erected and before the basement concrete floor 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 usually three to four inches deep, then a sheet of thick plastic vapor barrier was placed over the stone and the floor 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 doesn't take much to clog that drain.
What the fellow described as the drainage system that he thought was there was a variation of a French drain theme that was sometimes used- mostly unsuccessfully in the long run-- before the system I described was set in place via the building codes.
It could be that the silt that has clogged your areaway drain pipe over the last 37 years is as hard as a rock and will not yield to snaking or flushing with a high-pressure hose--but I'd try that first. That's where getting dirty comes in. If that fails then he was right to a degree about breaking up concrete. You'd 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. It's not wholesale demolition and you could do it yourself with a rented roto-hammer that will make breaking concrete relatively easy. Or call around to masonry contractors and describe what needs to be done and if they say they wont do it ask them for a reference of who might. It's really a small job and will take less then a day for those who know what they are doing. Install a bigger drain, too.
I see areaway stairs covered with both permanent or makeshift covers that tell me right away the drain is clogged. Controlling the other water sources getting into the areaway should be doable starting with the gutters directly overhead or the grade on the 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. Extreme but it works-- unless you lose power.
When you finally get the drain clear set a water permeable entry mat-- most are-- over the drain so the it intercepts the silt before it gets to the drain and won't let only a handful of leaves to clog up the works.
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