Orangeburg pipe
A bituminised fibre drain pipe used for sewer laterals from the 1940s to the 1970s that deforms and collapses with age.
What is Orangeburg pipe?
Orangeburg is made of wood pulp bound with hot pitch. Under sustained soil load it ovalises and eventually collapses, and its practical service life is far shorter than the clay or cast iron it replaced. Any home of the right vintage with an original lateral is a strong candidate for a sewer scope, because failure is invisible from inside the house until the line backs up. Replacement means excavation or pipe bursting and is expensive. Identifying the vintage and recommending a scope is one of the higher-value calls an inspector can make on a mid-century home.