"My problem involves a leak in a waste pipe"
Column #820 11/06/2010
On The Level
Q. I need help in solving a dilemma with my 100-year-old house in the Historic District of Annapolis. My problem involves a leak in a waste pipe, which I discovered when water leaked into my kitchen from behind a corner cabinet while a guest was running water into the sink in a third-floor bathroom. The waste pipe runs down a wall near the corner of my house from a third-floor bathroom, to a second-floor bathroom, to the kitchen, and then to the basement, where it can be seen.
At the time the leak appeared, I was working with a contractor who works in the Historic District. He suggested that a solution would be to have a liner put inside the pipe. This was not successful because the company that does this work was unable to get a camera down the pipe from the opening on the third floor under the toilet due to the turns that the pipe takes.
The next step was to have a plumbing company look at the pipe. They said the only solution was to replace the pipe from top to bottom, which would mean tearing out walls on the second and first floors and tearing out kitchen cabinets. My contractor then came up with another solution: To repair the part of the pipe that was leaking. He opened the wall on the second floor, a wall that he had previously opened when he remodeled the second-floor bathroom. He was able to find a crack in the pipe, seal it, and wrap the pipe. He then had to redo the work on the wall, which involved rebuilding a plaster chair rail. All has been well for about six months, but now water is leaking into the kitchen again--although only a small amount-- when the bathroom is used on the third floor. This does not happen when the second floor bathroom is used. I have already spent quite a bit of money trying to fix this problem.
The bathroom on the third floor is seldom used and is very small because it is built into a dormer. The bathtub/shower is never used because only a very small person can stand up in it, and the sink and toilet are used only by occasional guests. I am thinking about having the bathroom torn out and turning the space into a closet or storage area. The pipe could then be sealed off at the top. Tearing out this bathroom would be a lot less disruptive than would tearing out walls on the second and first floors since the third floor is rarely used. Simply not allowing the third-floor bathroom to be used is a short-term solution, but I need a permanent solution to this problem, especially since I may want to sell my house in a few years.
A. Your problem is unfortunately common to historic home owners who have century or near century old plumbing systems. As you have learned, gaining access to the leaking pipes frequently requires tearing out old walls and finishes and it’s not that the replacing the pipe that so costly as is the replacing of the what had to be removed to do it.
The pipe you describe is a cast iron Drain Waste and Vent pipe and goes from the roof where it’s the vent for the building’s plumbing system draining down with fixtures attached to it by smaller waste pipes to the connection of the City sewer line in the street. If you look carefully at one of those pipes you’ll see a seam where the two halves of the pipe were joined at the foundry all those years ago. That’s usually where I find them leaking. I will slip a new penny into the open seam to mark its location so anyone looking for it can find it quickly. Sometimes those old pipes just crack but mostly it’s a seam failure.
Capping it off at the top after taking that little top floor bath out can’t be done. You need the vent. By the way, if you leave the little bath unused, the traps for the sinks and tub and even the toilet can and will dry out allowing sewer gasses to back into the house. Remember sewer gas is methane and can be dangerous. I’ve seen folks try all manner of things to temporarily stop those leaks from wrapping the pipe to packing the seams with epoxy with varying results. If you can find the exact leak spot and stop it that way it will buy you, and or the next owner, some time before the inevitable, which is replacing the pipe with modern PVC waste lines. Remember, if you have a leak and know about it, you are legally bound to disclose that fact when you go to sell the house. The old cast iron surely outlived the original installers and owners and the PVC will surely outlive us.
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