Complete-Ad9574 t1_j1ws4rm wrote on December 27, 2022 at 11:50 PM

This means that the line is not properly angled, and is not fully clearing. Many historic buildings in Europe have exterior soil stacks. So the concept has been proven to work. Could also mean that people are putting too much TP in at one flush or other items , like Kitty litter, lint from washers, and other unmentionables.

NationalMyth OP t1_j1wsz57 wrote on December 27, 2022 at 11:56 PM

It had been working fine up until the Pilar vortex. They were gone for the week surrounding it, and had no issues beforehand. The house was kept at a reasonable temperature as well during the time in question. No litter, or obscene amounts of TP being used. The gutter apparently is routed into that pipe as well, but the rain ended well before freezing temps hit.

One toilet flush is what sent water into the walls, and the ice blockage at the blow out hole was discovered.