Q: Our 42-year-old house has drainpipes running through the basement. The little oozes at the joint were caulked. However, the black, tar-like coating on the extensions is wearing off, and rust is showing through. How should we approach this problem?
A: Forty-two-year-old drainpipes, those that are 2 inches or larger in diameter, are most likely made of either cast iron or copper.
Galvanized iron pipes were used for the smaller drains, such as those under a sink or shower. Copper drains are soldered together at the joints, and no "oozing" occurs. However, copper will wear from the inside out, and small, greenish clumps can be seen growing on the metal. The clumps are usually on the bottom of the pipe.
I also have found copper drains that have split open because of stress and chemicals that have been flushed through the drains over the years.
When you see clumps or cracks, it's time to replace the damaged sections of pipe. Save the copper you remove, because it is valuable and can be sold to metal dealers to help defray the costs of repairs.
Cast-iron pipes will "ooze" where reducing fittings have been installed to accept galvanized iron pipes. The tar-like substance you see is either the original pipe dope used by the plumber or raw sewage that has accumulated over the years.
Sewer pipes are not under constant pressure like water-supply pipes; therefore, leaks will occur only when waste is flushed through the drains.
The small leaks that do appear tend to seal themselves with an accumulation of an oozing gunk.
I would not be too worried about the rust that is starting to show under the tar. Cast-iron pipes will rust, but generally the oxidation that occurs is only on the surface of the pipe and should not present a serious problem.
When replacing older drainpipes, it is easiest to use PVC (polyvinyl chloride) drains, which are joined together with a solvent designed to chemically bond the sections together.
Where the PVC is joined to the older cast-iron or copper drainpipes, a rubber coupling with stainless-steel straps is used to form a "no hub" connector. You simply slide the rubber hub over the old pipe, insert the new PVC pipe into the other end of the rubber hub and tighten the straps.
What could be easier than that?
(Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at C. Dwight Barnett, Evansville Courier & Press, P.O. Box 286, Evansville, Ind. 47702 or e-mail him at d.Barnett(at)insightbb.com)
HOME MAINTENANCE
Post new comment