How does this vent/drain system look?

[Wren]

We bought an older house and are having to replace the plumbing completely. Supply lines as well as new drains including moving the sewer stub to the other side of the house due to tree roots and other issues. Here's a couple of drawings of what I figured out for the full bathroom. I'm not a plumber although I have done some plumbing and have a friend who used to be a professional who is retired. I'm confidant that I can do the work given I get someone to approve my plans. The work will be permitted and inspected.

I'm having to work around the existing layout of the bathroom structure. The only real concern I have is the toilet venting. It's going to be about 7' from the wet vent coming off of the washer and about the same distance to the wet vent for the sink. The inspector told me that a 2" vent will work up to 10' away from a fixture. It would be very difficult to vent to toilet any other way that I see; the walls are 2x4 and sit on a triple 2x10 band with the joists hung with joist hangers. The bathroom in this old house was originally a porch it seems. I need an installation that is going to be trouble free as the crawlspace under much of the house is really inaccessible due to the house being so low to the ground. The floors and sub-floors were removed, so for the purposes of installation, this could be considered a rough in. The house is pretty well gutted at this point.

How does this look?

 

[wwhitney]

Something like the drawing below would work. The lav is dry vented, and it vertically wet vents the tub and horizontally wet vents the WC. The lav and tub trap arms (from the trap to the vent connection) are limited in total fall to one inside pipe diameter. At the minimum 1/4" per foot rate of fall, that means up to 6' for 1-1/2" pipe and up to 8' for 2" pipe. (For the IPC, in force in Georgia). The WC drain has no such restrictions, it just needs to be vented before or as (wet vent) it joins another drain.

The washer can't be wet vented, so it needs its own vent as you show. It also can't participate in the bathroom wet vent, so for the WC to be wet vented, the washer has to join it downstream of the lav/tub connection to the WC drain.

Cheers, Wayne

 

[Sponsor]

 

[Wren]

Thanks very much, Wayne. I redrew the images to reflect the changes and to clarify a possible error that I noticed. In the overhead view, one can see that the line from the tub goes straight into the 3" and is joined by the other two lines. In the vent diagram, I corrected the lower part of the sink drain to reflect that the pipes A, B, and C are all horizontal (at least that's what I attempted).

 

[Reach4]

Thanks very much, Wayne. I redrew the images to reflect the changes and to clarify a possible error that I noticed. In the overhead view, one can see that the line from the tub goes straight into the 3" and is joined by the other two lines. In the vent diagram, I corrected the lower part of the sink drain to reflect that the pipes A, B, and C are all horizontal (at least that's what I attempted).

This one looks good. The other does not.

 

[Wren]

This one looks good. The other does not.

Are you referring to my drawing on the first post that Wayne corrected that needed modification?

I noticed that the WC drain was only 2" in the photo I posted earlier today. Corrected to show a 3" drain.

 

[Reach4]

Are you referring to my drawing on the first post that Wayne corrected that needed modification?

I am only referring to the two drawings on post #3.

 

[Wren]

I am only referring to the two drawings on post #3.

I believe I see the problem and error in my overhead drawing; the washer drain enters the 3" pipe upstream of where the tub drain joins the 3" pipe. Is that it?

 

[Reach4]

I believe I see the problem and error in my overhead drawing; the washer drain enters the 3" pipe upstream of where the tub drain joins the 3" pipe. Is that it?

Yes.

 

[Wren]

Here's the corrected drawing.

 

[wwhitney]

That drawing works for the IPC, assuming proper slopes and maximum falls on the tub and lav trap arms, as previously mentioned.

Cheers, Wayne