Simple Clog or Something Else??

A friend of mine recently had a home inspector complain about some DIY plumbing done behind her washer. Being moderately handy with piping/plumbing (though certainly not my specialty), I offered to help out.

The original issues were:
1. reverse grading of drain pipe
2. short stand pipe for washer drain (about 8")
3. very poorly done joints (mostly done with silicone!)

So I fixed these issues and things work fine... almost... ok, not at all.

Now every time they run their washer water drains properly through what I have set up (fixed grade, normal height stack, properly connected joints), but the water ends up backing up through the floor drain and flooding a section of the basement. The drain will drain all the water fairly quickly once the machine is done. I know virtually nothing about the existing connections in the floor, and it's all "downstream" (obviously) from where I did my "helpful" work.

My question is, is it a simple clog that just needs to be cleaned out, or since it drains rapidly after (and it didn't do this before) could it be as a result of something I did and should do differently?

Thanks!

Where does that washer drain go? Is it plumbed into something or does it just empty into the floor drain? More info please.

King

Sorry...

Here's a description:

First there's a double basin utility sink. After some "creative" plumbing involving 4 drains (which may be relevant and can give more detail, but I tend to think not) merged into one p-trap (all 1 1/2), the trap arm extends about 6' to a vertical drain/vent pipe (1 1/2 galvinized -- undersized, I know). (I think I remember something about that being a bit long for an arm before a vent, but I was trying to tread lightly in my re-engineering and didn't touch any of the sink stuff.)

About 3 feet from the vent pipe is where the washer ties into the trap arm of the sink (I thought a no-no because it could "suck" the water out of the sink's trap and vice-versa to the washer. Again, mildly re-engineered) The stand pipe (which is 1 1/2, because the rest of the system is 1 1/2) goes through a p-trap then ties into the waste arm via a wye.

After the washer ties in, it connects to the vertical "stack" via a san-tee approximately 3" off the floor.

The floor drain is maybe 6' away.

The general layout was something I neither planned nor thought much about, I just replaced some clearly wrong things in the middle

I have a guess as to what it is (that the vertical pipe everything ties into is really just a vent pipe for the drain, and inappropriate to tie a washer into without flooding), but I don't get why it never flooded before I made changes and now it does!

The changes (now that we've discussed the plan so thoroughly) were:
1. to fix a reverse grade on the arm from the sink (which went "up" ~2").
2. put in a stand pipe about 24" long.
3. replace the S-trap the stand went through before connecting to a san-tee on it's back.

None of those changes (I would have thought) would "create" the problem that now occurs. I'm wondering if it's just that the whole system was never properly designed (a distinct possibility) or if perhaps laundry "lint" has made a clog somewhere and it just needs to be cleaned out.

I'm sorry, I wish I had a picture!
- Jared

This time with Drawings!!

OK, so these are hardly masterpieces, but should make it easier.

The "Now" picture shows what the current system looks like... Perhaps someone can say "Yeah, that looks OK," or "That is total crap!" or something in between.

The pieces in red show what I changed (not much) and the "Then" pic roughly shows what it looked like before.

The main question is how to get rid of the recurring puddle on the floor.

The secondary question (which has no legal or financial bearing, just curiosity), is how my changes caused or just coincided with the problem.

Thanks for any input
Jared

The right way to plumb for a washer and a laundry tray

SeattleSoxFan,
What you showed in your line drawings is not right.
Each trap or fixture must have it's own vent.
Where is the vent for the floor drain?
It may be that running a washer over what I think is the floor drain vent is causing an overflow.

Even if you were to plumb it right, you may still have water backing up from the floor drain if the line is bad or blocked.

Thanks!

I think I knew that it was wrong (the separate venting at least), but was more or less patching the system that was there...

I never really thought that the pipe it was all tied into was not supposed to be used for drainage until now, basically just because it was working!

I'll tell them the not-so-good news...

Thanks Again!