[dp2010]

I'm repairing a leak in a drain vent pipe inside a wall (a cabinet installer drilled screws through the wall and into the pipe). The existing pipe is 2 inch "not for pressure" schedule 40 PVC (foam core). I checked the local stores and they only carry 2 inch solid core (pressure) schedule 40 PVC pipe. I need to replace a section about 2 feet long and want to know if its okay to mix the pressure (solid) and not for pressure (foam core) pipe in the same vent line. I'm guessing it wouldn't make any difference, but figured I better check just in case. Also, I'm assuming the pipe and fitting dimensions are all the same? Thanks in advance for any advice.

[ballengerb1]

I would not even bother cutting out that pipe. There is only passive air and sewer gas moving in a vent. Put a screw back in the hole and put some adhesive or sealant on the screw.

[dp2010]

ballengerb1, thanks for the reply. Here's the issue: the vent pipe drops down into the basement and is capped off (just a couple feet below the screw holes) as a future vent for when we add a bath in the basement. During times of heavy rain/snow, water accumulates in the capped off pipe and when it rises to the level of the screw hole it leaks. Therefore I do need to fix the pipe and need to know which kind of sch 40 I can use.

[ballengerb1]

So does this future vent actually go all the way to the roof and vents to open air? The rain and snow accumulate because its capped, this will be open to the sewer when you eventually add the lower bath room. If I picture this righ you just need to put a temp cap on the roof top of the stack

[mygirlsdad77]

dp2010. Yes you will be just fine using solid pvc with the foam core. Outside diameters are the same, as are the glueing techniques. Not a problem at all.

[Milo Dolezal]

Cut the pipe exactly where the hole is, insert Flex-Seal coupling and tighten the 2 s.s. bands. Job is done in 2 minutes. No need to buy any pipe or glue at all...

[truck 41]

You can just dab some glue into the screw holes, that should seal it right up if the holes aren't to large.

[CHayn]

I completely agree with mygirlsdad and/or Milo. You obviously already have the pipe exposed so you might as well replace it rather than put a bandage on it and risk future problems.

[speedball1]

I agree with the other experts.
Not serious enough to replace the section of pipe. Grout the hole with primer and PVC cement or follow Milos advice and install a shielded metal coupling, (see image) over the hole. Good luck, Tom

[dp2010]

Thanks to all for your replies and suggestions. I found two screw holes (or drill holes?) in the pipe. There was very little space to work in and the holes were on the opposite side (I actually opened up the wall in a room opposite the bathroom so I wouldn't have to mess with anything in the bathroom). I decided to cut the pipe just above the holes and then dropped the bad piece down into the basement. It was just about three feet long and was capped off in the basement. I ran a new capped off piece up from the basement and connected it to the existing pipe. Less than $10 in parts and I'll feel better knowing I have a pipe without holes behind the wall. AND I got to teach my son how to cut and glue PVC pipe! Thanks again, this site is a great resource.

[speedball1]

Thanks for the update, Tom

[Milo Dolezal]

Job well done ! Don't forget to stop by in the future with your next plumbing related question ! Milo

[dp2010]

I hope it's okay to add a quick follow-up question to my original post. My original issue was with a water leak in a vent pipe that goes into the basement and is capped off (available for future remodeling). I repaired the leaking pipe but wondered if there is a way to keep water from accumulating above the capped end of the pipe.

When the water level gets high enough, it will go into the sewer drain, but there is still an area about 3 to 4 feet long that can have standing water inside the pipe. Would it be a good idea to install a pvc drain valve of some type at the end of the pipe, so I could occasionally drain the water out of the line and then re-close the valve? I was thinking of a PVC ball valve which I would glue on the end of the line instead of the end cap. I would then remove the valve at some point in the future when we put a bathroom in the basement and need the vent pipe.

Would this be an acceptable and/or proper solution OR should I just not worry about the standing water? Any thoughts or opinions are appreciated.

[Milo Dolezal]

Absolutely, you don't want any standing water in that pipe. As you suggest, you can install a drain valve or shorten that pipe to minimum.

[hkstroud]

Why not just go up on the roof and put a cap on the pipe? Don't glue, just slip cap on the pipe. Write "this vent pipe is capped" on the exposed section in the basement so you will remember when you put in the bath.

[ballengerb1]

I agree with Harold and said as much back in post #4

[dp2010]

Just to clarify - the capped off vent pipe in the basement will serve a future bathroom in the basement but it is not a dedicated vent. It also serves a current bathroom on the first floor, so capping off the vent pipe at the roof is not an option.

[ballengerb1]

Then put a rain cap on there stack. Thanks for the explanation, I had missed this point. http://www.plumbingsupply.com/vent_pipe_filters.html