Copper pipes aren’t old, but they are leaking

DEAR BARRY: My house is only 15 years old, but the copper water lines already have green spots, and some of these spots are leaking. I thought copper pipes were supposed to be corrosionproof. What could be causing this problem?

— William

DEAR WILLIAM: Copper pipe is known for its general resistance to corrosion, but it is definitely not corrosionproof. In fact, here is a list of possible causes for corrosion in copper plumbing:

• Impurities in the water. Water with high acidity or high concentrations of dissolved minerals such as salt, sulfates, or iron can cause copper pipes to corrode. Corrosion can also be caused by high levels of dissolved oxygen or by some forms of bacteria. In some areas, these conditions commonly occur in well water. A lab analysis of your water can help to determine if any of these contaminants are present.

• Electrolysis. Another common cause of copper pipe corrosion is electrolysis, typically occurring where copper pipes and galvanized steel pipes are in direct contact. If your plumbing has these kinds of connections, dielectric connectors should be installed. Dielectric fittings can be made of brass, or they can be unions with rubber or plastic bushings to insulate the copper from the steel.

• Flux in the pipes. When green spots are seen on copper pipes, a common cause is that too much flux was used when the pipes were being installed. Flux is a gel that plumbers apply to pipe fittings before the joints are soldered. Competent plumbers are careful to avoid getting flux inside the pipes when soldering the fittings. When flux residue coats the interior surfaces of copper pipes, corrosion can gradually work through the pipes, resulting in pinhole leaks. In cold water lines, the flux can remain and cause gradual damage.

• Rust particles in the pipes. When corrosion and leakage occur in hot water lines, a common cause is particles of iron and steel from an old rusted water heater. Corrosion of this kind usually happens in horizontal pipes, where the rust particles can settle onto pipe surfaces when the hot water is turned off. You should have your water supply system evaluated by a qualified licensed plumber to determine whether these or other causes are the source of your problem.

DEAR BARRY: Our home inspector says the house we’re buying has damaged insulation under the building. He says some of the strips are hanging down, and many are in shreds. What causes fiberglass insulation to degenerate like that?

— John

DEAR JOHN: Fiberglass insulation does not degenerate. It has to be damaged by some overt force, usually in the form of varmints. These can be wild varieties, such as rats, raccoons, opossums, etc., or domestic types, such as cats seeking shelter.

If your subfloor insulation is shredded, check the vent screens around the building. Most likely, you will find at least one that has been torn or is missing.

Replacement screens can be purchased from most hardware and building supply stores. Barring animals from your crawl space can prevent further damage to the insulation and will keep animals from using your crawl space to perform their daily duties.

To write to Barry Stone, go to www.housedetective.com.

ACTION COAST PUBLISHING