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Author:
Marko1 (MO)
Hi, wondering what possibilities i haven't considered.
I have a mystery leak, small, intermittent, suddenly occuring a few months ago.
Small leak noticed on basement floor dripping off kitchen sink abs 1.5" drain.
Small trickle running down outside of abs pipe.
Very small quantity of water and intermittent in occurrance. First noticed after a snow storm. Never happened before in 35yrs of occupancy.
Abs goes up inside the outside wall of house behind kit sink.
San tee comes out thru wall into cab for the sink trap conx and continues vertical up to tie into Steel vent.
There is a window above sink so steel vent has 90d bend and continues 3 to 4 ft horizontal
before turning 90d up and out roof.
my current assumptions:
Leak cant' be coming from sink strainers or supply lines or sink rim to counter joint as they are inside the cab/room, not inside the wall, so no way the water could jump inside the wall to get to the vent pipe.
Leak can't be coming from roof jack flashing(or roof safe)at vent pipe because water wouldn't turn 90d and run 4ft horizontally, it would have dripped off the pipe near the bend inside the wall and appeared in a different location in the basement.
I also inspected the seal between flashing and vent and appears perfectly sealed.
I cut open sheet rock under cabinet to see vertical pipe as big as I could under the circumstances - pipes, counter top etc.
The leak is on outside of abs vertical vent coming from above the level of the san tee.
It could be coming from joint between abs and steel but hard to tell as it's up above where I can get to, inspection mirror showed some moisture at that joint but can't tell if its the source or just gathered there because of the wet insulation that was in the wall cavity.
If leak is coming from inside vent it means water is getting into top of 1.5" steel vent at roof, so i made a sheet metal cap that completely covers vent top but allows air, similar to a chimney cap...leak still occured after that was installed like maybe a week later.(as i said it's intermittent, goes away then comes back a week later or so)
I thought maybe window sill was leaking but close inspection shows it is in perfect condition, no cracks, no loose caulking, no sign of anywhere a leak could get in.
The exterior siding is lap cedar 5" siding. I thought water could possibly come thru the exposed nail heads which are slightly rusted-house is 80 yrs old. But if that were the case I should see some nails poking thru the sheathing up inside the wall with water dripping off the tips of the nails...I don't see any nail tips penetrating the sheathing.
The insulation in the wall cavity was soaking wet when I opened wall so i removed it all except for a bit that is wedged above the horiz vent run and below the window sill where i can't get to it to remove it...perhaps it still had some residual moisture which eventually dripped down, thus causing the small leak after i put the vent cover on the vent at roof.
the only way to get to the vent conx between abs and steel would be remove siding from outside wall or tear out countertop and tile backsplash to get to from inside, neither option desirable, so trying to think of anything else i could do to find and stop leak.
sorry for such a long post but wanted to point out everything i've tried or thought of
Thanks for any ideas
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Author:
Wheelchair (IL)
Condensation Perhaps? You could have the waters from the leak analyzed to determine its source.
Best Wishes
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Author:
Marko1 (MO)
Thanks Wheelchair,
I had also thought of that but can't in my mind figure out where it would come from since the wall had been insulated?
Also if there were conditions to cause condensation I would have expected seeing it before 35years.
there was a lot of water in the insulation indicating leak had been collecting for a long time before it finally started dripping down the pipe to be seen in the basement...
so i guess that wouldn't necessarily rule out condensation, but i usually think of condensation creating small amts of water that often dry before becoming visible?
also i was thinking that if it were condensation i would have seen beading on the horizontal pipe that i can see in the inspection mirror and it was dry.
that's what lead me to conclude that it must be water from the vent leaking at the joint between abs and steel...although i was surprised to think much water could collect in such a small orifice at the roof...especially after i put the little cap on the vent?
Do you think there's any chance water could get into a small hole like a 1.5" vent pipe at the roof from rain or snow? i would think it was so small that it would dry before creating a leak but maybe not?
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Author:
Wheelchair (IL)
Mother Nature and Gravity............. are not on your side.
Best Wishes
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Author:
Fixitangel (NC)
Where your vent pipe exits up thu the roof there may be a rubber gasket that has a small crack or gap due to age. I would use a good silicone sealer or black roof adhesive to seal it positively. I've seen mystery leaks show up downhill from such a source before.
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Author:
bernabeu (SC)
if, repeat if, the vent was installed properly it would be pitched to the drain so water 'could' turn the corner and run 4' horizontally on the 'top half'
open up a little more and hit the roof vent flashing with a garden hose (maybe somehow scented with a little peppermint)
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
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Author:
techman (PA)
TRY WATER WITH COLORED DYE AT THE ROOF VENT (DOWN THE VENT); TIGHTENED COUPLING AT THE TRANSITION BETWEEN STEEL AND ABS
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Author:
Marko1 (MO)
Thanks PA,
the problem is I can't get to the abs/steel joint without removing siding from outside wall so no way to tighten. but the dye water is a good idea. maybe by some miracle i could cut a section out of the abs above the san tee and unscrew the upper section out of the steel 90. then put a new pvc piece with tons of pipe dope up in there and reconnect with rubber boot...but is it advisable to leave rubber boot inside a wall and cover it up?
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Author:
WC (VA)
The vent pipe extending thru the roof (flashing) must/will have movement. The "seam" at the pipe and roof flashing "may" not be water tight due to age etc. A visual inspection from the roof top may not detect a defective seal.
MAY OR MAY NOT BE YOUR PROBLEM - BUT CHEAP EASY INSURANCE FOLLOWS:
"IF" you do not want or do not think replacement of the complete flashing installation is necessary, you may try the following cheap easy and effective repair.
Purchase a proper size vent flashing with a RUBBER boot insert. Remove/cut the rubber insert from the new flashing. From the roof top, slide it over and down the vertical vent pipe to cover the existing pipe/flashing seam.
The above is the cheaper way to go. ($5 - $8). Just make sure the rubber insert is big enough to completely cover existing seam.
A actual vent pipe repair boot is available for aprox $19 but I favor rubber and am not sure of the material they are made from.
Check the Orange big box for "Vent Flashing" - also - "Vent Flashing Repair".
A check of this web sites supporter "PlumbingSupply" for "flashing also has a stand alone "vent shield" for $3 - $4.
Edited 1 times.
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Author:
Marko1 (MO)
WC, just saw your post, thanks, that's a great idea
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