Hello, I have to move a vent stack to make room for Solar Panels. Does it matter where in the run the vent stack is connected? Right now, from left to right the run is, 2nd floor sink, 4ft pipe, T for 2nd floor toilet, 4ft pipe, T for 1st floor sink, 6ft pipe, T for 2nd floor shower, 6ft pipe, T for vent stack, 20 ft pipe, first floor sink, toilet. All of the pipe is 2 1/2" except for the vent stack. That T is (2 1/2") 3" (2 1/2"). The 3" section goes into 3 1/2" & then through the roof. The T also goes straight up. I need to move the vent stack to the left, moving it closer to one end then the other as well as moving it up the roof closer to the ridge vent.

Can I just cut the vent stack T out, put a coupler in its place and then put the vent stack between the 2nd floor toilet & 1st floor sink as well as changing the layout of the piping to the vent stack in the attic? As I have to move the vent stack up the roof towards the ridge vent, the central a/c trunk is in the way in the attic. Can I have the T go up for 1ft then into a 45 then 4ft of straight pipe into a 90 to go through the roof?

Should the T to the vent stack be the highest point in the run so that any rain that might get into the pipe runs down to the sink, shower, etc and does not pool somewhere in the pipe in the attic?

Thanks

Thanks

Vent fittings have direction so could be a bit problematic moving things, but if you can make the move within that 20 feet of piping then you should have no issues making the change.

As you said, just be sure to have the "T to the vent stack be the highest point in the run so that any rain that might get into the pipe runs down to the sink, shower, etc and does not pool somewhere in the pipe in the attic".

If the change in vent piping goes past fittings with direction then by code the fittings need to be changed, but common sense also tells me that you will be OK if you don't, OK?

Glad to discuss more if you want, OK?

Mark

Vent fittings have direction so could be a bit problematic moving things, but if you can make the move within that 20 feet of piping then you should have no issues making the change.

As you said, just be sure to have the "T to the vent stack be the highest point in the run so that any rain that might get into the pipe runs down to the sink, shower, etc and does not pool somewhere in the pipe in the attic".

If the change in vent piping goes past fittings with direction then by code the fittings need to be changed, but common sense also tells me that you will be OK if you don't, OK?

Glad to discuss more if you want, OK?

Mark

Hi Mark,

Thanks for responding. Do you think I would have any issues if I changed the diameter of the last few feet of pipe from 3.5" to 3". There is maybe about 3 ft of 3.5" pipe. I wanted to use the Perma-Boot (Home Depot) for the vent pipe. The largest dia is 3".

The plumbers increased the pipe to 3.5" because code required it according to the number of fixtures in the home. Reducing the vent size to 3" probably won't be a major issue, but as a licensed plumber I certainly can't recommend that you do it!

Good luck!

Mark

The plumbers increased the pipe to 3.5" because code required it according to the number of fixtures in the home. Reducing the vent size to 3" probably won't be a major issue, but as a licensed plumber I certainly can't recommend that you do it!

Good luck!

Mark

Hi Mark,

If I take a sink & toilet off that run and give them their own 3" vent stack, would I be within code for the rest when I reduce it to 3"? I would end up with a vent stack for 2nd floor sink, 2nd floor toilet, 1st floor sink & 2nd floor shower & another vent stack for a sink & toilet. Both 3", this would also eliminate about 20ft of 2.5" pipe.
If I can't use the 3" pipe, are there any codes against using 3.5" black ABS for the vent stack through the roof. I want the black pipe because it will be high up on the roof and seen from the front of the house. I think that it would look better the white PVC.

Thanks

Sounds reasonable, but I would probably just reduce the 3.5" to 3" first... try it out and see how everything worked... of course, I didn't say that, right?

I see no issue with the ABS plastic, but I can't say if your town/city will or not. Call your inspector and ask if you are concerned, OK?

Good luck!

Sounds reasonable, but I would probably just reduce the 3.5" to 3" first...try it out and see how everything worked....of course, I didn't say that, right?

I see no issue with the ABS plastic, but I can't say if your town/city will or not. Call your inspector and ask if you are concerned, OK?

Good luck!

Thanks for all of the info!

;)