Is tying into the existing stack or adding a new roof penetration preferred?

[Brian Kehlmeier]

I am DIYing the plumbing in my new addition and planned on tying the drains into the main stack in the basement and also the vents into the main stack in the attic. As with all of these projects, little questions pop up that I did not anticipate, like this one:

If I am going to insert a hard ABS sanitary tee on the stack in the basement, I would have to push the main stack pipe up through the roof boot, then back down. I do not want to get up on the roof, so spraying with soap is not something I really want to to do. Am I correct to assume that I will probably damage the boot in the process? Is using a repair boot, with clamps, an inferior joint?

 

[John Gayewski]

Generally you'd use a no hub clamp to insert your fitting. You wouldn't slide the stack up unless your prepared and know what will happen. It depends on the boot type.

 

[Sponsor]

 

[Daniel Collick]

I am DIYing the plumbing in my new addition and planned on tying the drains into the main stack in the basement and also the vents into the main stack in the attic. As with all of these projects, little questions pop up that I did not anticipate, like this one:

If I am going to insert a hard ABS sanitary tee on the stack in the basement, I would have to push the main stack pipe up through the roof boot, then back down. I do not want to get up on the roof, so spraying with soap is not something I really want to to do. Am I correct to assume that I will probably damage the boot in the process? Is using a repair boot, with clamps, an inferior joint?

Some “roof jacks”, is what we call them in Washington State, may not be caulked, so you could possibly slide the pipe upward through the roof jack, but as mentioned you’d want to know what will be effected. If the roof jack is caulked, you’ll probably separate the caulk. If there are other vents tied in where you can’t see them, they may be effected or just make it more difficult to raise the pipe up high enough to install the new fitting. Two steel jacketed “mission” style couplings can be used to do what you’re referring to. They’re available to couple different or similar materials, such as plastic to plastic or plastic to cast iron, so on and so forth.

 

[Reach4]

I am DIYing the plumbing in my new addition and planned on tying the drains into the main stack in the basement and also the vents into the main stack in the attic.

You may not be allowed to use that "stack" as a vent, since drainage is likely being carried from the floor above.

 

[wwhitney]

You may not be allowed to use that "stack" as a vent, since drainage is likely being carried from the floor above.

There's no floor above an attic.

Cheers, Wayne

 

[Reach4]

There's no floor above an attic.

"If I am going to insert a hard ABS sanitary tee on the stack in the basement ..."

That is why I was thinking basement. But I can see that I maybe should have interpreted things differently.

 

[wwhitney]

But I can see that I maybe should have interpreted things differently.

The part you quoted says "tying . . . the vents into the main stack in the attic."

Cheers, Wayne

 

[Reach4]

I would have to push the main stack pipe up through the roof boot, then back down. I do not want to get up on the roof,

Get a roofer to look and take pictures. Or ask your friend with the drone-mounted camera.

If you have an older or higher-quality house, you may have a lead roof vent boot. That is normally folded over the top of the pipe, and into the pipe. If you have that, you could get that unfolded, do your stuff, and then get it folded back.

 

[Jeff H Young]

If possible dont disturb the upper pipe going through roof , keep it supported at all times. then no problem

 

[Reach4]

A riser clamp supported by carpentry is a good way to support the pipe thru the roof before you start cutting.