Roof vent flashing Replace Now Sink trouble!

[MDXWITHSPEED]

Hello everyone!

Okay.. So I had a water leak when it rained in my kitchen ceiling. I decided to cut the drywall and inspect were the cause of the leak was the problem. I removed the insulation behind drywall and found a 2 inch cast iron pipe with a hole (pipe was old and rusted) in it. The 2 inch pipe travel to my roof and down to my basement. I asked around about the pipe and I was told that the pipe is called a vent stank pipe.

A couple of days later it rain and the leak was coming from the top of the vent pipe and I notice the roof wood around the pipe was wet and damage. I got on the roof and inspected the black roof caulking around the pipe and found it to be very damaged. Also, were the pipe is coming out from, on the top of the roof it was installed with a threaded reducer coupling mated with a 4 inch pipe. So inside the home the pipe is 2 inch and when I get on the roof the pipe is 4 inches.

Unfortunately, I did not take pictures of the repair but here are some pictures of what was replaced.

I travel to the hardware store and purchase PVC pipe, elbows, and the vent gasket. The original pipe did not have flashing with a gasket. On top of the roof the old pipe was installed with a lot of black roofing caulking around the roof shingles. I installed the gasket with the flashing and were I cut the drywall that's were I installed the new PVC pipe going out to the roof.

So here is where I need help! I completed the repair and now when I turn on the kitchen sink, about 1-2 minutes of water running the sink starts to drain very slowly and I have to wait for the water to drain down the sink to keep the water running, no problems before vent pipe repair. (I forgot to mention, I did not use a reducer coupling were the pipe goes from 2 inches to 4 inches. I used straight 2 inch PVC pipe out to the roof.) I removed and cleaned all the plumbing tubes under the sink and my sink stills starts to drain very slow and slower. All the plumbing in all the rooms are okay, no problems with water back up just in my kitchen sink. I really do not know what is the operations for the vent stank pipe are! But, since I did not use a traducer coupling, mating a 2 inch to 4 inch pipe will that cause my kitchen sink back-up problems with the sinks water drainage?

 

[Geofd]

Is it possible for you to look inside the vent from the roof with a flash lite sounds like something has fallen inside the pipe when you made the repair there are also pipe cameras out there not sure if you can rent them
You other option is to snake the vent from the roof but I would want to know what’s in there first

 

[MDXWITHSPEED]

Thank you Geofd!

So if something fell in the vent pipe, that will cause my slow water back-up drainage in my kitchen sink problem that I have present now?

 

[Geofd]

Thank you Geofd!

So if something fell in the vent pipe, that will cause my slow water back-up drainage in my kitchen sink problem that I have present now?

I think so if it worked fine before(except for the leak) now after the repair it’s changed,it’s possible pipe scale fell into the vent, or the drain

 

[MDXWITHSPEED]

I think so if it worked fine before(except for the leak) now after the repair it’s changed,it’s possible pipe scale fell into the vent, or the drain

Thanks! I will not be able to get on the roof and inspect what may have fallen into the vent. I may not be able to get the job done till the 3-4 days. But, if I get up in the roof sooner I will update my problem and fix.

 

[fixitron]

The reason that the original pipe went from 2" to 4" above the roof is to prevent hoar frost. In cold climates when it gets down to the single digits, the warmer moist air venting out of your soil stack vent will freeze into hoar frost. The frost will choke off the vent.
As for the kitchen sink drain, I cannot imagine that something the right size fell into the soil stack to completely choke it off. You only mention the kitchen sink, but what about other drains? If your sink drains slowly because of a clogged vent, then your toilet and tub would back up even worse because the water would drain much faster.
"The more you look, the more you see, and if you don't look, you don't see."

 

[MDXWITHSPEED]

As for the kitchen sink drain, I cannot imagine that something the right size fell into the soil stack to completely choke it off. You only mention the kitchen sink, but what about other drains? If your sink drains slowly because of a clogged vent, then your toilet and tub would back up even worse because the water would drain much faster.
"The more you look, the more you see, and if you don't look, you don't see."

Thanks for the reply! Well, I did not have no trouble with my kitchen sink water drainage before the roof vent fix. I have 2 bathrooms and 2 kitchens in my house. I checked all the plumbing in the rooms and I have no trouble expect in my kitchen sink. Right after I completed my roof vent pipe repair, my kitchen sink drains very slow and I have to shut off the water and wait. I did check all the pipes under the sink for blockage and cleaned them very well, did not help with the problem with my sink. I just don't know, by me just using a 2 inch pipe straight out to the roof, instead of 2'- 4' pipe caused my kitchen sink problem? Furthermore, I just went outside and toke a picture of the back of my home. You can not see the vent pipes from that angle (sorry) but, on the right and left side on top of the roof there's two vent pipes for my home. I'm just mentioning this for understanding my plumbing in my home.

So, on Wednesday or Thursday I will be removing the 2' pipe on the roof, and will be replacing it, just like before. 2' to 4' pipe. Using PVC pipes.

Thank you for the help! I can take all the information about this vent stank pipe that can help me.

 

[Jeff Handy]

It might just be a coincidence.

Your sink drain line probably needs to be snaked clean.

Or else maybe you blocked off the vent pipe with a rag or something, and left the rag stuffed in there when you replaced the vent pipe.

 

[Geofd]

You can snake from the roof , I have done it before I would get a camera and see what’s down there. I guessing it’s a peice of pipe

 

[MDXWITHSPEED]

Hey everyone!

I was finally able to get on the roof yesterday and replace the 2' vent pipe to a 4' inch, just as like the original old vent pipe.

So, I was having trouble with my kitchen sink drainage like I've mention. I received some great information with all the replies that came in!

My trouble was not the 2' pipe I installed straight out to the roof, and not using the 4' like I should of have! I was able to get a hold of a power drain machine that I used to unclogged the sink. I was not to sure how far the length of the rod was, (picture of rod machine) but It had to travel down very far to finally get the sink unclogged. I do not know what clog up my sink, but for about 2 seconds I did fell some pull when feeding the rod down the drainage. Receiving all the great information about this vent pipe I received here, lead me to focus on the sink because it was great to know that a blockage with my vent would of gave me plumbing problems all around my home. Also, if I did not replace that 2' to a 4' vent pipe, I would of had big trouble in the winter time ! My sink getting clog was a 'sign' for me to replace the pipe correctly and not have me thinking what problems I may be having in the winter time when my plumbing is backing up!

Thank you everyone! And, I really enjoy doing a lot of DIY repairs around my home!