Advice on Unused Vent with Roof Penetration

[ttthhh]

I need advice on what to do with this 1-1/2" vent.

Some background. The primary bath was remodeled about 15 years ago -- before I owned the house. In the process, the old shower area now has the toilet room. To service the toilet, a new 2" vent was run as in the diagram. It runs up into the attic, turns 90 degrees, then lays flat on the trusses for about 4 feet, turns 90 degrees (still flat) and the another 4 feet until it turns up and exits the roof. My roof has concrete tiles. The 2" vent is sloped fine and the total horizontal run in the attic is probably 8 feet total.

In the process, they abandoned the old 1-1/2" shower vent. But, rather than fix the roof penetration, they just capped off the bottom of the vent pipe and left it hanging from the friction of the roof collar. Well, you know how well that worked. I found this pipe laying on its side in the attic with daylight coming in the roof penetration. Fortunately, I'm in a dry climate and no one ever noticed this in 15 years!

I'd rather not fix the roof penetration and I stuck the pipe back up through the flashing collar. This won't last once the capped off pipe fills with water.

Can I just do as in the second diagram and change the 2" 90 to a sanitary tee and connect the old 1-1/2" to that? Then I don't need to get rid of my roof penetration and the pipe won't fill with water and fall out or freeze. It seems logical to me, but venting is a lot more complicated than most people have any idea.

 

[Storm rider]

I don't see any problem with what you propose to do. The tee can be a vent tee or a santee.

The existing 2" line that you say "lays flat on the trusses" should be sloped 1/4" per foot so that any moisture that does get into the vent will drain down.

 

[Sponsor]

 

[davidgilbert23]

It sounds like you're dealing with an old vent pipe that was left abandoned when the bathroom was remodeled, and you’re trying to figure out how to handle it without having to fix the roof where it used to vent. From what you’ve described, they capped off the bottom of the old 1-1/2" vent pipe, but didn't properly secure it, so it fell over, leaving a gap where water could come in.

Your idea of using a sanitary tee to connect the old 1-1/2" vent to the new 2" vent seems like a practical solution. This way, you wouldn’t have to worry about the roof penetration anymore, and it would prevent the old pipe from filling with water, which could cause it to fall or freeze. However, venting systems can be tricky, and it’s important to make sure the modification wouldn’t affect the overall function of the plumbing. It would be a good idea to check local codes or consult a plumber to confirm that this approach is safe and up to code.

 

[christopherdbrown]

I need advice on what to do with this 1-1/2" vent.

Some background. The primary bath was remodeled about 15 years ago -- before I owned the house. In the process, the old shower area now has the toilet room. To service the toilet, a new 2" vent was run as in the diagram. It runs up into the attic, turns 90 degrees, then lays flat on the trusses for about 4 feet, turns 90 degrees (still flat) and the another 4 feet until it turns up and exits the roof. My roof has concrete tiles. The 2" vent is sloped fine and the total horizontal run in the attic is probably 8 feet total.

In the process, they abandoned the old 1-1/2" shower vent. But, rather than fix the roof penetration, they just capped off the bottom of the vent pipe and left it hanging from the friction of the roof collar. Well, you know how well that worked. I found this pipe laying on its side in the attic with daylight coming in the roof penetration. Fortunately, I'm in a dry climate and no one ever noticed this in 15 years!

I'd rather not fix the roof penetration and I stuck the pipe back up through the flashing collar. This won't last once the capped off pipe fills with water.

Can I just do as in the second diagram and change the 2" 90 to a sanitary tee and connect the old 1-1/2" to that? Then I don't need to get rid of my roof penetration and the pipe won't fill with water and fall out or freeze. It seems logical to me, but venting is a lot more complicated than most people have any idea.

Leaving the old vent pipe improperly capped and exposed allowed water to enter the attic, potentially causing roof leaks or even structural damage, i have faced this situation and have bear costly water damage repairs , the cost of fixing roof from couvreur toiture mascouche is additional. So always ttry to fix such thing quickly to avoid costly repair and stress of handling all these worst situations.

connecting the old 1-1/2" vent to the new 2" vent using a sanitary tee seems like a reasonable approach to address the abandoned vent and prevent water from accumulating in the pipe. make sure the 2" vent is sloped at 1/4" per foot to allow proper drainage of any moisture. However, it's crucial to verify that this modification won't interfere with the overall venting system or violate local plumbing codes.

 

[John Gayewski]

Not sure about the odd comments on this thread but your idea is good.

 

[John Gayewski]

Usually an unused pipe gets tied into the other vents so it can be used at anther time and any water that enters its absorbed into the piping system.