leaking vent pipe

Discovered a drip on outside of vent pipe in second floor bathroom that eventually wore a hole in the ceiling. Replaced the vent cap and drip seemed to go away for a while. It soon returned and I had a roofer check it out and he put on another vent cap. Drip has returned again after a couple of weeks. Any ideas on what to do next would be appreciated. I need to fix the ceiling but want to fix the drip first.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I wonder if the replacing of the vent cap has moved the pipe and in doing so temporarily moved any joints below fixing the leak. The safest method of stopping the drip would be to check all joints in the pipe as that is where any leak will come from including the roof penetration. Also get in the ceiling space to try and pinpoint that leak. Sorry i cant help more, shame we cant get a photo or diagram.
Regards
Chris
www.interiordezine.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
vent pipe shouldn't have any water in it. Maybe you have a leak where it comes out of the roof..
tim1198
rivahrebel wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
tim1198 wrote:

It will when it rains. It is possible, but I think unlikely that rain water falling into the pipe could leak past a bad joint.

--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Agree. I got a new roof. Roofers moved the whatchamacallit (conical sheet metal device) where the water-heater vent pipe comes through the roof but didn't recaulk it at the top. Rainwater hitting the side of the pipe ran through and dripped on top of the heater. Silicone caulk at the top of the cone fixed the problem. Since vent pipes aren't supposed to contain water, it seems this lack of a seal is a likely cause of the problem. Or maybe the roofing has failed, letting water get under it to reach the pipe.
SJF
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If this is a burner vent pipe, check that any horizontal section slopes up toward the roof. A low spot can trap condensation or rainwater and cause a leak. Normally any water in the pipe drains back to the burner. Don Young
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yeah, my problem with water leaking at a (plumbing, not burner) vent stack turned out to be the roofers not installing a flange.
Before I realized that, my first thought was to cap the vent (there was no cap initially). When that did nothing I decided to rip out the damage in the kitchen ceiling and there it was -- the back side of the shingle. The rood deck is 1x4's -- nothing like a round pipe going through a square hole to cause water damage.
My solution was strategic caulking (with asphalt caulking) under the shingles, around the vent (primarily above, of course). So far so good, but I suspect I'll have to revisit it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.