Bathroom/laundry venting questions - need help to proceed

[gringoloco]

Hello to the group, I just found the site and already like what I've read.

I'm doing a bathroom/laundry rehab and I have two ?? that I can't answer.

1. I have a double vanity that was redone years ago and they added the extra plumbing under the sink and used white flexible stuff. I'm redoing it with copper and ABS in the wall. I saw a previous post from "lindalou" 05/25/08 and I think it answers my 1st question. To add the left sink I will add a sanitary tee below the original one and vent that line up and over to the 2" vent. I also will convert the existing washer drain to a deepsink drain. (see vanity photo)

2. I then need to add a washer drain to the other 2" vent which has a sink and shower from upstairs bath on it now. Can I do this or will the washer have problems? Both of the 2" vents go to a main 4" stack less than 40" away and I believe they drain straight down into the 4" line heading to the street.

Any comments will be greatly appreciated.

Tnx
Bob

[gringoloco]

This was my first post on this site so if I didn't sound like I really needed help then I have understated my problem. I didn't get much done yesterday, today was spent sizing pictures for this post and cutting bushes and I took off tomorrow hoping to finish this plumbing project but it ain't looking good so far.

I just don't want to do all the work only to have the shower drain into the washer or visa/versa.

If anybody sees something fundamentally wrong with my plans please let me know.

Again, any help will be appreciated.

Tnx
Bob in East Tennessee

[Redwood]

You are adding a washing machine to a 2" line that has a shower on it?
Could be ugly!

[gringoloco]

I was using the chart in B&D's Home Plumbing:

sink = 1 unit
washer = 2 units
shower = 2 units total = 5 units

maximum fixture units for vertical drain = 10 units
(horizontal drain max is 6 units)

I didn't think the load would be too much but I didn't know if the water draining from above would affect the operation of the washer drain.

tnx
Bob

[Redwood]

There are many places where code would prohibit the washer from being on the same line as the shower before going to a larger dia. pipe. Reason being even a partial blockage of the smaller 2" pipe would have a geyser of wash water overflowing the shower stall in short order... Surprise! You have 30 gallons of water flooding across the floor of your bathroom!

Now we are informed there will be water coming down this line from above. Even if it was permitted by code where you live this presents a problem with venting. You cannot have a vert. wet vent between floors under any code that I know of.

[gringoloco]

Tnx for your observations, Redwood, I now see what you mean about a vertical wet vent. I went to the library and read another book on plumbing and they explained a little more clearly about the different types of venting.

What if I redo the p-trap for the standpipe and extend it over a foot to the right in the photo and add a tee for the deepsink on the 2" drain?

Then the 2" drain would have:
2 lavs = 2 units
1 deepsink = 2 units
1 washer = 2 units
total = 6
(chart says a vertical 2" will handle 10 max)

I would then leave the other 2" drain alone. Also the main drain in the house isn't 4", its 3". (house was built in '77)

[patrick88]

I think you should sketch what you have and what you want done. If you do things right today you will have fewer problems later.

[Redwood]

I'm lost on what your saying, but, if what you are saying is putting the washer standpipe tie in back on its original pipe I have no problem with that. 1' is well within the length allowed for a dirty arm.

Take a look at this picture to see how the venting needs to be done. Notice both the washer and sink traps are protected by the vent.

[gringoloco]

Redwood, Tnx for the photo, it helps me out a lot. Now if you add 2 small lavs off to the left you have my final plan. I had the building inspector stop by yesterday and he said the same thing about using the existing drain. He also mentioned moving the other drain (2") over a little with some 45s so that the standpipe ends up where I need it. Hopefully I can finish up this weekend and get on with the sheetrock.

Tnx again
Bob