Ron and Cris from Ranserve pointed this out to Steven.

Apparently, when the house was originally built, the plumber drilled through the paired beams that hold up the second floor, above the kitchen, to run the vent stack for the kitchen sink up through the framing to the roof. That plumber took out more than half of both of the paired beams. As a result, the second floor at what will be the master bedroom — if you place a golf ball on that floor, as Steven did, that golf ball rolls around vigorously, unable to find anything level to rest on.

This is wrong.

Ranserve will be fixing this, per the structural engineer, at F and E — see Sketching the structural plan.

Compounding the error in the ceiling, the plumbers also compromised the studs that support the top plate when they drilled the studs to run the vent stack into the stud bay from the sink.

This malice took forethought, because they clearly took the time to drill through four vertical studs and a vertical shim, as if there is never ever a structural reason to nail four vertical studs together.

What also amazes is that an inspector approved these errors when the house was built.

Ron and Cris advise that inspectors today will “red flag” failures like this.