We are remodeling our master bath and want to eliminate the shower and replace it with a tub; however, after demo we can see that not only does the vent have to move, but the drain will need to be moved as well.

What I'd like to know is whether there are any options (without a violation or future problems) without hacking up the concrete to move the vent and drain. If the vent/drain have to be moved, I'd like an estimate for the cost to do so.

I'm attaching a rough drawing and an image that shows how we want to end up.

P.S. The toilet isn't that close to the wall, it is staying in it's original location.

Thanks,
-dew

Quote:

---

Originally Posted by damadake

We are remodeling our master bath and want to eliminate the shower and replace it with a tub; however, after demo we can see that not only does the vent have to move, but the drain will need to be moved as well.

What I'd like to know is whether there are any options (without a violation or future problems) without hacking up the concrete to move the vent and drain. If the vent/drain have to be moved, I'd like an estimate for the cost to do so.

I'm attaching a rough drawing and an image that shows how we want to end up.

P.S. The toilet isn't that close to the wall, it is staying in it's original location.

Thanks,
-dew

---

Can't really answer any of your questions without seeing pictures of the current rough-in and groundwork.

I tried to draw it on the first picture. The shower drain and vent are actually in alignment. I can see this now that the shower walls are down. The clean out is off the rear of the house outside and is has a y connector for the other bath down the hall.

The water lines would have to be moved also, but that is out in plain sight, so the move is easy. The new wall partition would be slightly back of where the shower door was previously, and I expect the vent and the new water lines would be relocated on that wall.

Does this help any? Thanks for your reply!

Ideally the tub vent would be re-located to the tub stub-wall where the tub valve will be installed -- But again, I can't really offer much if I can't see pictures of the current rough-in and groundwork.

Rough-in and groundwork? Is this how the existing pipes run under the slab?

After looking over your drawings your project seems doable, without breaking up the slab, only if you platform the tub. You could elbow the drain back to the shower raiser and elbo the vent under the platform floor over to the wall where it could be run up to the attic to revent back into a existing roof vent. You would also have to cut the water lines down under the slab and cut channels in the cement for the water lines and then patch over them. To give you other options, as Growler has stated, we would need to know what you now have under the slab. Good luck, Tom

Is there any code violation in using an elbow on the vent? Would this present any issues functionally?

The water lines are run in the ceiling, not the slab, so that looks fairly straight forward.

Thanks for the reply!

Quote:

---

Originally Posted by damadake

Rough-in and groundwork? Is this how the existing pipes run under the slab?

---

It is.

No matter how you approach this, you will have to bust up at least some of the concrete.

The drain, trap-arm and vent are all going to have to be reconfigured and moved to the stub wall -- And in the case of the trap arm, it will have to be re-sized, but all of this will need to be done under the slab.

And the reason I keep asking for pictures is because I need to know which direction the main drain line grades to, which fittings were used to pick up the shower and what materials were used in the original groundwork.

Quote:

---

Originally Posted by speedball1

After looking over your drawings your project seems doable, without breaking up the slab, only if you platform the tub. You could elbow the drain back to the shower raiser and elbo the vent under the platform floor over to the wall where it could be run up to the attic to revent back into a existing roof vent. You would also have to cut the water lines down under the slab and cut channels in the cement for the water lines and then patch over them. To give you other options, as Growler has stated, we would need to know what you now have under the slab. Good luck, Tom

---

I considered this option, but not knowing if the original work was flat-vented below the slab makes me hesitant to make this recommendation.

Is there an easy way to tell whether it was flat vented? I'm happy to do whatever I can.

Quote:

---

Originally Posted by damadake

Is there an easy way to tell whether it was flat vented? I'm happy to do whatever I can.

---

Not without breaking up concrete from the vent to the shower drain.

Quote:

---

Originally Posted by damadake

Is there any code violation in using an elbow on the vent? Would this present any issues functionally?

---

Venting horizontally below the flood rim of a fixture is allowed as a last resort and only if the proper drainage fittings are used.

Growler,

OOPS! My bad! I forgot about the tubs flood rim. Is there any way we could make this work? Tom

Quote:

---

Originally Posted by speedball1

Growler,

OOPS!! My bad! I forgot about the tubs flood rim. Is there any way we could make this work? Tom

---

Well, I'm kind of one dimensional when it comes to 'by-the-book' plumbing, which limits me to tearing it all the way out to just before the vent/trap-arm fitting and taking off from there.

His unwillingness to break up the necessary amount of concrete in order to find out just what his options are is making me lose interest in this thread, so I think I'll leave the rest up to you.

Is breaking up the concrete is required to find out what is necessary? Sorry, I didn't see the prior posts when I made the last one.

Quote:

---

Not without breaking up concrete from the vent to the shower drain.

---

How much concrete has to be broken up to do this, and if I have to do this, wouldn't it make sense to do just that, or does it not require as much breakup?

I really appreciate the responses, and I'm willing to do what I need to do to get it right. Thanks!

The reason Growler's concern is that its possible for water to back up into the vent if a partial blockage occurs in the tubs drain line.

This is a non-typical example of flat venting, as you can see, a portion of the vent is horizontal below the actual fixture -- Should the drain ever plug up, it is possible that the horizontal portion of the vent will also plug up.

As for this being a non-typical example, I had plenty of room to roll the combination wye and 45 completely up, but in most cases, you will not have the depth to roll the combination of fittings up as high as I did.

Thanks for all your answers. I think I'm starting to get an understanding.

Now, to check this out, would I get like a concrete blade for the circular saw and score parallel to the vent/drain pipe and sledge pieces up? How far below the surface will the pipes be? The vent/drain is ~17" from the edge of the slab.

Everything is torn out of the bath with the exception of the shower floor, and I'll probably get that out tomorrow.

Last but not least, is this something that I should be able to do without significant risk, or should this just be left to a pro?

Just thinking through this a little more based on the last comment. If the vent was fitted with a 45' and the tub drain was raised over the height of the flat vent, would this also solve the problem.

Here is another drawing so you can see what I mean. If it's a dumb idea, just say so. I can accept rejection. :-)

Don't misunderstand my intent. I want solution to be correct; however, if a less complicated solution is available, I would prefer it.

Thanks to both of you guys for taking the time to help me out!

Quote:

---

Originally Posted by damadake

Just thinking through this a little more based on the last comment. If the vent was fitted with a 45' and the tub drain was raised over the height of the flat vent, would this also solve the problem.

Here is another drawing so you can see what I mean. If it's a dumb idea, just say so. I can accept rejection. :-)

Don't misunderstand my intent. I want solution to be correct; however, if a less complicated solution is available, I would prefer it.

Thanks to both of you guys for taking the time to help me out!

---

It isn't that the vent must be raised above the tub drain -- Nothing in plumbing is that easy.

The vent must be raised above the flood rim of the tub before going horizontal, and the flood rim is the very top of the tub when installed.

Also, another thing to take into consideration is the size of the p-trap.

A shower has a 2" p-trap, while a bathtub has only a 1-1/2" p-trap.