Common plumbing parts in older homes — and what to watch for
5 min read · D. Cohen & Sons
A lot of houses in this part of New Jersey were built before mid-century, and the plumbing in the walls reflects it. That's not a problem — it's just a different set of parts. Here's what tends to be back there and what it takes to repair it.
Galvanized steel supply lines
Gray, threaded, heavy. Common in homes from before the 1960s. It corrodes from the inside, so pressure drops over decades and joints seize. When a section is replaced with copper or PEX, the transition needs a dielectric union or a brass fitting between the steel and the copper, or the joint will corrode again. We stock the transition fittings; bring the diameter of the pipe.
Cast iron drain and waste
The big black stack and the horizontal drains. Joints on the oldest installations were packed with lead and oakum and are not meant to be taken apart. Repairs today are done by cutting out the bad section and bridging with a no-hub coupling — a rubber sleeve with stainless bands. Measure the outside diameter of the pipe; 3" and 4" are common but not guaranteed.
Compression and packing-nut stops
The shutoff under an older sink often isn't a quarter-turn ball valve. It's a multi-turn stop with a packing nut under the handle. When it drips at the stem, the fix is usually tightening or repacking that nut, not replacing the valve. When it won't close fully, it's the washer. We carry packing and washers by size.
Radiator air vents and valves
Steam and hot-water radiators each have their own vent and valve types, and they aren't interchangeable. A steam vent that hisses continuously or a radiator that stays cold is usually a vent. A radiator that leaks at the pipe is usually the valve packing. Bring the old vent — the thread and the pressure rating are both printed on it.
Odd sizes
Some older fixtures use thread sizes that aren't on a modern shelf. The part exists; it's just not common. This is the situation where a photo or the old part matters most, because it's the difference between an adapter that works and three that don't.
The short version
Older houses aren't harder to repair. They just need the right part on the first try. Bring the piece, or call ahead and describe it.