Yes, but that is so essential I didn't feel the need to mention it. The original installation (probably more than 70 years ago) seemed to use something more like plaster - I had to chisel it out, but it wasn't hard - or maybe the wax takes a set over the decades.

Of course, now I know the sewers are haunted. When the pipes were open, I could often hear this eery sound, "Bong bong, bong" echoing up the pipes. The water trap should keep this under control.