Double san-tee ?Mistake?

[Hookr1]

I'm a new homeowner that has various DIY projects (unrelated to previous professional trade experience).

I added a new bathroom to my house on the first floor. I plumbed the new bathroom into a secondary drain pipe that was previously used as a washing machine drain leading straight outside without additional fixtures. Currently, It has a washing machine, sink, shower, and toilet all on a 3 inch line connecting to previously mentioned drain.


This 3 inch is laying horizontally at the correct pitch, and with more research I found the proper connector would have been the double elongated tee. Toilet and washing machine are connected to the straight run, sink and vent on one side, and shower on other.

I had a plumber come out and scope the whole line because i was having backup issues when I flushed the toilet. It would come up shower and under toilet flooding the bathroom. He found roots that were causing a bit of a damn, he cleared them out with a pressure wash, and I didn't have issues for months until today where I'm back to square one.

He suggested if it happens again to get a high pressure toilet, and before I do so I'm looking for guidance if that will fix the issue, or if I'm back to jackhammering to fix my mistake.

Any advice is appreciated, thank you.

 

[wwhitney]

If you used a double san-tee with the barrel horizontal (so all 4 connections horizontal), that's definitely wrong. The double san-tee in that orientation will give you flat unsloped side entries, best case. Not sure that would be the cause of your backup issues, I don't have the experience to say. I imagine it could be compounding a root issue, but seems like if it were the sole cause, the problem wouldn't have cleared up for months.

The best way to do a 4 way horizontal connection is actually two separate wyes (the upstream one could be street). That way you can adjust each wye individually so that the side branches have the correct slope. Next best is double wye where the barrel is sloped 3%. That allows you to slope each side entry at 2%, although you have to be careful to get the two sides the same, if one side entry is sloped more, the other side entry is sloped less. A double combo would have the same slope problem as a double san-tee, the side entries will end up flat and unsloped, best case.

Cheers, Wayne

 

[Sponsor]

 

[Jeff H Young]

I think rebuilding it is the way to go.

 

[hj]

If yo have a root problem, all a "high pressure" toilet will do is overflow faster when the line starts to be obstructed.. It has little to do with that sanitary cross, (a double tee is a different animal).