Cast-iron pipes shouldn’t be oozing tar

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Q: My house was constructed in 1955, and in the basement laundry area I have cast-iron drain pipes that are oozing tar from the joints. What products/procedures would I use to repair them? --U. W. A: Pipes of the type you describe are called bell and spigot. The male end of the pipe -- the spigot -- fits into a flared female fitting on the other end of the pipe -- the bell. After assembly, the joint was sealed by first packing it with oakum, which is a thick hemp fiber saturated with tar, then sealing the joint with molten lead. The "oozing" that you're seeing is the tar from the oakum, which typically indicates that the lead seal is failing. The building codes no longer allow lead in plumbing systems, so to repair the existing joints you would need to repack them by first removing the old oakum, then forcing a metal fabric material into the joint. It's similar to steel wool, and takes the place of the oakum. The joint is then sealed with a product called soil cement, whic...