Need some drain help

[Otahyoni]

I'm redoing my bathroom and need some advice on how to redo the drains.

Here's a drawing of what I have now:

I'd like to keep the toilet and sink where they are, but the tub will be replaced by a shower so I'll need to redo that part. The current toilet drain is cast iron with the sink and tub being galvanized.

I would like to cut the cast iron at the verticle just before the clean out and replace everything above with PVC. What I'm not sure about is the routing and what order to plumb things in.

Can you guys help set me straight?

 

[phishfood]

Here are a couple of drawings.

 

[phishfood]

This is a detail of what the current vent should look like when you are done.

 

[Otahyoni]

Crap. This means I'm going to have to make one wall thicker.

Does any horizontal section of vent have to be sloped towards a drain?

Does the shower have to be vented?

Another thing, currently the sink drain drops down through the floor. If i had to move it into a wall with a vent it would be right over the center of a doubled joist. How would I get around this?

Edit: forgot a word...

 

[Otahyoni]

Heres some better pictures of what my current setup is:

 

[Otahyoni]

Ok... I've been throwing ideas around and I think I've got something that will work...

This is views from a couple angles, but my rough idea.

The way I drew it, the sink and shower go into the top of a 3x3x2 sanitary T. Only the sinks vent goes through the roof, the showers goes to the sink vent in the attic. The shower's drain comes between the joists and drops down from above the sink's drain via a 1.5x1.5x2 sanitary T.

Does this sound ok? I'm getting a new roof, so nows the time to move the vent if I need to...

 

[phishfood]

I don't know Indiana code, but in my area it is to code (and works very well) to vent the entire bathroom through the sink's vent. However, since you have the height to work with, and there is already a vent there to work with, it won't hurt to vent the shower as well. The way you have the shower drain/vent arrangement drawn middle right of your drawing is correct, make sure you do it just that way. The sink vent needs to be there, even if it isn't there at present.

 

[Otahyoni]

Thanks for getting me set, phish.

 

[roliza]

Are you doing all this by yourself

 

[Otahyoni]

Yes. I have plumbing experience, just not as a trade.

 

[Zanne]

Otahyoni, when you asked about slope on a horizontal run, you need to have the horizontal part of the waste drain slope downward at 1/4 inch per foot and any horizontal runs of vent need to have 1/4 inch per foot slope upward.

If you have wet vents (meaning the air will have to travel through the same pipe that is carrying waste) it needs to slope downward. The p-trap can not be more than 5 feet away from the vertical vent.

It looks like you have everything within the right distance though.

I'm not an expert so if I'm wrong, someone correct me.