This is a guest blog post by our very own Peter Schilling.
I've lived in my 1923 South Minneapolis bungalow for five years, and up until last week had yet to get my sewer lines cleaned out. Naturally, as a Structure Tech employee (I'm a Client Care Coordinator, so I schedule inspections, thank you very much) I hired Drain Busters, the company we use to conduct sewer line inspections on properties we examine.
Everything went smoothly until Jeff Brewer, the Drain Busters employee, pulled back the cutter blade from the sewer line. Wound around the blade was a gigantic, football-sized mass of what looked like paper, hair and black gunk. Jeff said, "Man, that sure looks like Orangeburg to me!" Then, looking at it closely, he added, quietly, "Boy, I sure hope that's not Orangeburg." From the tone of his voice and his wide eyes, I was worried.
Later, I asked Joe Whitters, the owner of Drain Busters, to enlighten us on this mysterious Orangeburg.
History of Orangeburg
"Orangeburg is a pipe material that was used for sewer lines here in Minnesota, from roughly 1965 to 1977," he said. It's a very unique kind of pipe, made of layers of wood pulp or sheathing pressed together with layers of tar in-between each wrap, and was also known as fiber conduit or bituminous fiber pipe. A 4-inch diameter pipe would contain anywhere from 20 to 25 layers of pitch pressed wood pulp. "Imagine a paper birch tree," he explained. "You peel off the layers and spread tar in-between each layer until you get a dense tight packing."

Because iron was in high demand during World War II, Orangeburg was a great replacement. After the war, it was perfect for building those massive tracts of inexpensive bungalows, as it was cheaper and easier to use than metal pipe. Used as early as 1860, this type of pipe was manufactured primarily by the Orangeburg Manufacturing Company, named after the New York town where they're located.
Orangeburg today
"We rarely see Orangeburg nowadays," Joe said. Often, when looking at a pipe with a camera, Orangeburg can be confused with a cast iron pipe, as they look almost identical from inside. "You can tell an iron pipe because of the rust blistering the inside," he added. As Orangeburg is made of wood and tar, obviously it won't rust.
Orangeburg pipe was once thought to have been impenetrable to tree roots. "When this pipe was new, that may have been the case," Joe said. As Orangeburg ages the tar begins to dry out which allows moisture to absorb into the actual walls of the pipe, weakening it, thus allowing tree roots to enter and crush it.