Can vent go downward below the highest fixture?

**dlarrivee** · 03-13-2011, 10:34 PM

You can tie into that 3" so long as you're 6"+ above the flood level rim of the lav...

How did you plan on possibly going AROUND the 3" with a 2" anyways?

**Cubey** · 03-13-2011, 10:43 PM

Ah, now I see. Besides the fact you'd have to go below the sink (not a good thing) you'd have to rip out the wall all the way around the bathroom and replace it to do it that way. While I'd be as hesitant as you about cutting a hole in my roof, I'd probably do that before I'd rip out sheet rock from 3/4 the way around the bathroom. Sounds to me like you either need to cut into that 3" iron pipe and put in a tee (which sounds like more trouble that it's worth) or go through the roof. Anything else would be kind of going beyond what's reasonable.

**speede541** · 03-13-2011, 10:48 PM

Originally Posted by keano016

That is a Cast Iron 3 inch vent so it is challenging to connect to.

Keano, I don't typically give advice here since I'm new at this and still feeling my way through my own plumbing projects. But I just wanted to share with you my experience with CI as a DIYer.

In my case, I had a 4" CI vent to tap in to in order to install a Wye for a second toilet vent. The location of choice was in a closed wall, behind the toilet. Naturally, I had to remove the toilet and open the wall the gain access to the pipe, but it sounds like you're at that stage already.

Then, with nothing but a 4" angle grinder, I began cutting away at the pipe. The grinder easily got half way through at my cut marks, then I had to back out and slice a wedge out of the section I was removing. A couple of vertical cuts along the sides, and the front half of the piece I was removing practically fell out. This left me a big opening to get at the back half, which came out just as easily. The cuts were clean and smooth and straight. I slapped the no-hub fittings on there, slid the metal bands out of the way, rolled up the rubber coupling, and the wye slid right into place.

It was intimidating to start, but actually a very straight forward and satisfying project. Only two words of caution:
- Griding iron is extremely messy. Wear a mask. Wear goggles. Protect finished surfaces with plastic.
- Iron pipe is heavy. Make sure what you're cutting is supported -- both ends, before you get to cutting. Riser clamps for iron pipe are cheap, and will prevent an unsupported pipe from dropping through the floor or pulling through the roof.

http://www.terrylove.com/forums/show...-CI&highlight=

**keano016** · 03-14-2011, 05:22 AM

Originally Posted by Cubey

Ah, now I see. Besides the fact you'd have to go below the sink (not a good thing) you'd have to rip out the wall all the way around the bathroom and replace it to do it that way. While I'd be as hesitant as you about cutting a hole in my roof, I'd probably do that before I'd rip out sheet rock from 3/4 the way around the bathroom. Sounds to me like you either need to cut into that 3" iron pipe and put in a tee (which sounds like more trouble that it's worth) or go through the roof. Anything else would be kind of going beyond what's reasonable.

This is an attic space, I have access on both sides of the high walls, and there is space behind the small wall ( a duct runs behind that 2 ft wall) so I do not need to rip any sheetrock, the vent pipe would just go behind that wall.

**keano016** · 03-14-2011, 05:24 AM

The 3 inch CI is not in the wall, but a foot behind it and I have access to that area. Maybe few pics would help.

**jadziedzic** · 03-14-2011, 05:31 AM

You really do NOT want to tie a plumbing vent into the exhaust line of a high-efficiency furnace, regardless of whether it is "plastic and easy to tap into" or not.

You do realize that home owners are not permitted to do their own plumbing work in Massachusetts, right? As much as I'm an avid do-it-yourselfer, at times I realize it is really better to hire a professional; not only do they have the knowledge and tools to do the job correctly, and probably in significantly less time that you could - to say nothing of safety concerns. If you go to sell your house some day any kludged-up plumbing work could be noticed by a home inspector, and you might need to drop some serious out-of-pocket bucks to correct the problem before you can sell.

**keano016** · 03-14-2011, 06:04 AM

View from inside the bath

here is the space behind the toilet and sink wall

Cast Iron close up. Where the 20 amp wire is going is where i was planning of running the 2 inch pvc to go behind the wall of the window and come on the other side, where the tub wall is (bellow)

**keano016** · 03-14-2011, 06:12 AM

This is the opposite wall behind the tub where I have a 2 inch metal venting that can be easily taped into.

And here is the high efficiency furnace venting

**keano016** · 03-14-2011, 06:20 AM

Originally Posted by jadziedzic

You really do NOT want to tie a plumbing vent into the exhaust line of a high-efficiency furnace, regardless of whether it is "plastic and easy to tap into" or not.

You do realize that home owners are not permitted to do their own plumbing work in Massachusetts, right? As much as I'm an avid do-it-yourselfer, at times I realize it is really better to hire a professional; not only do they have the knowledge and tools to do the job correctly, and probably in significantly less time that you could - to say nothing of safety concerns. If you go to sell your house some day any kludged-up plumbing work could be noticed by a home inspector, and you might need to drop some serious out-of-pocket bucks to correct the problem before you can sell.

I agree with you that the job needs to be done right, not just do something mickey mouse job just because it is easy. I am soliciting input. If going around that 2ft wall and below the highest fixture is not a solution up to code (this is a diy that I feel comfortable doing) then my other options are going through the roof of tapping into the CI, for either of these options I will be probably hiring a plumber for. I am intimidated by the CI and not sure of the support I need to put to it (this is a 3 story high pipe, so it has some serious weight).

Going through the roof seems the easiest solution, although that would mean 4 vents poking through my roof. I ve never done it so I may hire a plumber to do it.

**keano016** · 03-14-2011, 06:51 AM

Originally Posted by speede541

Keano, I don't typically give advice here since I'm new at this and still feeling my way through my own plumbing projects. But I just wanted to share with you my experience with CI as a DIYer.

In my case, I had a 4" CI vent to tap in to in order to install a Wye for a second toilet vent. The location of choice was in a closed wall, behind the toilet. Naturally, I had to remove the toilet and open the wall the gain access to the pipe, but it sounds like you're at that stage already.

Then, with nothing but a 4" angle grinder, I began cutting away at the pipe. The grinder easily got half way through at my cut marks, then I had to back out and slice a wedge out of the section I was removing. A couple of vertical cuts along the sides, and the front half of the piece I was removing practically fell out. This left me a big opening to get at the back half, which came out just as easily. The cuts were clean and smooth and straight. I slapped the no-hub fittings on there, slid the metal bands out of the way, rolled up the rubber coupling, and the wye slid right into place.

It was intimidating to start, but actually a very straight forward and satisfying project. Only two words of caution:
- Griding iron is extremely messy. Wear a mask. Wear goggles. Protect finished surfaces with plastic.
- Iron pipe is heavy. Make sure what you're cutting is supported -- both ends, before you get to cutting. Riser clamps for iron pipe are cheap, and will prevent an unsupported pipe from dropping through the floor or pulling through the roof.

http://www.terrylove.com/forums/show...-CI&highlight=

Your work looks great. Thanks for the advice but I am just that brave. Really worried about the support of that Ci that I would cut because it is 3 stories high.

**jimbo** · 03-14-2011, 07:19 AM

Originally Posted by jadziedzic

You really do NOT want to tie a plumbing vent into the exhaust line of a high-efficiency furnace, regardless of whether it is "plastic and easy to tap into" or not.

.

Maybe I missed the post where that came up?? PLEASE do not attempt to connect a plumbing vent to any part of the HVAC flue, or anywhere else!

**keano016** · 03-14-2011, 08:59 AM

Originally Posted by jimbo

Maybe I missed the post where that came up?? PLEASE do not attempt to connect a plumbing vent to any part of the HVAC flue, or anywhere else!

But the fresh air supply for the furnace is ok to be connected to the HVAC flue?

**jimbo** · 03-14-2011, 10:58 AM

Originally Posted by keano016

But the fresh air supply for the furnace is ok to be connected to the HVAC flue?

Huh?? ..

**jadziedzic** · 03-14-2011, 11:34 AM

The fresh air supply and the flue are NOT connected; that wye fitting just before the pipes exit the roof is what is known as a concentric vent. Here's a picture of what it looks like: http://www.alpinehomeair.com/viewcat...categoryID=346

**keano016** · 03-14-2011, 06:21 PM

Originally Posted by jadziedzic

The fresh air supply and the flue are NOT connected; that wye fitting just before the pipes exit the roof is what is known as a concentric vent. Here's a picture of what it looks like: http://www.alpinehomeair.com/viewcat...categoryID=346

That makes sense. Very informative video. Thank you for the link.