Cast iron pipes in the wall cavity is one of those details that customers rarely appreciate, until they’ve lived in a home without this option. The noise in an interior wall containing an outfall waste vertical plumbing pipe in ABS plastic is substantial. Sounds like the dam upstream has broken…watch out here comes the water.

We try to get these runs in an exterior wall, surrounded by insulation, but just the same, a run done in no-hub cast iron plumbing is far quieter. Don’t think this applies to horizontal runs however. In that case, the roughness of the interior of cast iron may accentuate clogs.