Speculate on the cause of leak thru ceiling directly below toilet when flushed?

[JimNY]

2nd floor toilet (approx 55 yr since installed, current flushometer probably less than 20 yrs), when flushed water leaks through 1st fl. ceiling at the location below that toilet.

Would a professional absolutely need to open up the ceiling from below for a look-see before diagnosing/repairing? It happens to be in an extremely inconvenient location, so wondering if it could be worked from the 2nd fl only. (As a layperson can only best-guess such a problem could be due a failing "wax-ring" seal.)

 

[Jadnashua]

The first thing would be to remove the toilet and see what can be seen from there. There are numerous possibilities, a few of which are:
- the wax ring is compromised
- the toilet has cracked
- the pipe has cracked

 

[Sponsor]

 

[JimNY]

Thanks for the info. Step 1 being

The first thing would be to remove the toilet

is kind of what was hoped...

It's just that two (different location) past 2nd Fl->1st Fl leaks in that house were both first investigated through the ceiling below, but were resolved solely from the 2nd Fl with no need for access from below.

(PS The second possibility noted is very interesting; didn't know that porcelain was something that could fail without a physical or temperature shock.)

 

[Jadnashua]

Keep in mind that most toilets use a wax ring to seal it to the drain. Wax is not resilient...IOW, it is not a spring. If the toilet rocks at all, it will compress the wax when it rocks one way, and when it rocks back, it will open a gap. That may not cause a water leak, but can. It will, however, open that gap up from the sewer to the home, and you could experience some sewer gasses present in the home.

Older porcelain doesn't tend to crack unless it has an impact or you overtighten the attachment bolts. But, it can happen.

 

[Terry]

Do check the floor seal first. That's the most common issue.