bathroom addition

[scottd7812]

Hello
Im a diy'er and im in the process of adding a bathroom to my house and would like to do the plumbing myself.

My bathroom will be approximately 6' x 8'. It will have a toilet and a sink on one wall, and the shower on the opposite wall.

The existing drain runs above the concrete floor, out the wall the underground to my septic tank. I will build a floor for the new bath, to hide the plumbing. My qeustion is can i tie into the 4" drain and do this. The vent which is also 4" runs up the outside of the wall to under the soffit

 

[phishfood]

First, the vent CANNOT terminate under the soffit, it must rise at least 6" above the surface of the roof. A soffit is generally an air intake for the attic, and that can cause sewer gas to be sucked into the attic.

If you can post up a drawing of the layout of the bathroom, where the drain line comes in and where it runs to, and any other fixtures it catches, and also the location of the vent, we should be able to help you out.

 

[scottd7812]

thanks for the info on the vent i didnt think that would fly. Ill try to get a drawing or sketch posted

 

[scottd7812]

Hope this will work. Can i connect the toilet, sink, shower, and washer into the 4" drain and leave the vent outside and extend it up through the roof. Any and all help is appreciated.

 

[phishfood]

Let's see if I managed to do this:

 

[johnjh2o]

I think you missed the vent for the shower.

John

 

[AQualityPlumber]

Yes, you are missing the shower vent. Also it would be better to wet vent the lav into the toilet. The laundry will operate better independently.

 

[phishfood]

No, the lavatory drain serves as a wet vent for both the toilet and the shower. IPC code only requires 1 1/2", but I prefer 2" for that, as a slightly clogged 2" pipe will still provide a sufficient wet vent.

I don't know what code is in effect in the original poster's area, but I am 100% certain that would pass inspection in my area, and work properly. Any pressure variations caused by the washer discharge would be relieved through the lavatory vent.

 

[johnjh2o]

I tend to agree with AQuality. Plus I don't like coming through the side of the vanity. Many of these new vanity's will have a draw in that location. I also try to avoid putting any fixtures between the toilet and it's vent. Just my opinion.

John

 

[AQualityPlumber]

I live in Washington. That would not fly here. Upc code says that you can wet vent both of those fixtures into one vent. However, you must increase the wet vented section by one pipe size based on the min drainage discharge pipe size. Example is the min for the toilet vent is 2 and the min drain size for the laundry is 2 therefore the wet vented section needs to increase to 2 1/2 but you will only probably find 3 pipe, so that is the correct size to be legal. Another example is the toilet vent is 2 the lav drain is 1 1/2. This means the wet vented section is fine at 2 because it is one pipe size larger then the min for a lav. The venting past the section should be sized appropriately per code with the dfu and the cross sectional calculated.
Make sure you put a clean out on the vent slightly higher then the wash machine. This will make snaking the drain a very easy process without removing fixtures.

 

[scottd7812]

Thanks for all the advice.

If i run the drains and vents a phish described, which will pass inspection where im from, do i still need to run the vent outside of my house?

Why would i need to run the vent through the side of my vanity and not out the back as normal?

Thanks again

 

[phishfood]

The only reason I drew it to the side is that the wall behind the washing machine will be getting a little busy with the laundry box, water lines, electical, dryer vent, etc. It is entirely possible to put the lavatory drain/vent behind the lavatory. Referencing the size of the vanity in your drawing, it led me to think that there wasn't enough room for drawers, so I drew it in the side. The vents either need to go out through the roof or out through the wall and tie back into the outside vent.

 

[scottd7812]

Thanks phishfood

I had not taken into account of all the extras in the wall. You are correct there will be no drawers in the vanity, so going out the side is not a problem.

Wish me luck as i tackle this project.

Thanks to all Scott