Is this vent pipe installed incorrectly and the source of my prob

mnestroyFebruary 20, 2012

I have discovered a very high level of moisture in my attic and as a result the insulation a near the gable end is very damp and i now have mold all in my attic.

I suspect that the Furnace vent that was installed on the lower attic/roof which is placed approximately 15inches away from the gable wall/siding of the 2nd story attic is the source of the moisture/mold.

I have witnessed hot steam/humid air venting out of this pipe and due to its proximity of the upper attic and siding I suspect this is how the moisture is coming in. I have gone out there on dry days and the siding was dripping water like it had just rained.

As you can see form the attached photos the vent is placed very close. The second photo is from the inside of the upper attic on the opposite side of that wall. You can see the wall itself is very damp and the insulation in that area is a different color/damp.

Can anyone tell me if

1. They believe this is in deed the source of moisture and not poor attic venting? I only moisture build up on this gable wall and the insulation elsewhere is dry.

2. Is this vent placement against code? I am not an HVAK installer just a common home owner but I have done several searches and found references to NFPA 54 stating "" that the flue gases are directed toward brickwork, siding, or otherconstruction, in such a manner thatmay cause damage from heat orcondensate from the flue gases"

3. if this was installed incorrectly is the company that did the work legally liable for correcting the problem and fixing the damage caused? I used a very large company and had ever permit pulled and passed inspection by the city.


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I'm not an HVAC, nor construction pro, however I suspect that this is in fact your source for the moisture problem.

Did this problem exist prior to the install? I am not a believer of coincidence.

Looking (and judging) by the pitch of the roof, I would have to say that the vent is not high enough for proper draw. It goes without saying that it is TOO close to the exterior wall.

If in fact you had this inspected by a city, village, etc. inspector, I would HIGHLY doubt their overall integrity and intelligence. And yes, you do have recourse. The beauty of inspections - it protects you and keeps the contractors on their toes.

Good luck!

    Bookmark   February 20, 2012 at 7:24PM
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What is the location of the furnace? What furace do you have? What is the efficiency rating?

    Bookmark   February 20, 2012 at 8:29PM
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What type of ventilation does your attic have? Ridge vent? Vented soffits? Can you see the baffles in the attic at the eaves? Poor ventilation 12 months of the year is the more likely suspect to the moisture in your attic rather than a furnace that operates 5 months out of the year.

    Bookmark   February 21, 2012 at 12:29AM
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Your venting situation may only be compounding another preexisting problem. I don't see any metal flashings installed between the roof where the vent stack is and the adjacent wall. Moisture may be infiltrating at this point. I also see a very low roof vent next to the vent pipe. Does this get snow covered in winter and become useless?

Consult a building inspector, an engineer or the permits department again to properly resolve ALL the issues.


    Bookmark   February 21, 2012 at 9:50AM
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the vent flashing is incorrectly installed.
instead of being attached on top of the shingles
the top and sides up to or past the pipe
hole should have been under the shingles to
keep water out.

the wall to roof of the next attic in the picture
doesn't look to be flashed.
as water enters this area it will be just
as it looks. darker at bottom of wall
where the water enters, and lighter where
it wicks up the wall.

you can wrap the pipe for the heater vent
with insulation inside the attic.
to keep condensation out of the attic.
the vent has to steam to exterior
to release the pipe.

I would correct the flashing of both
the wall and the vent cap, insulate
the pipe in the attic and see if wall
doesn't dry out.

it would help to know what climate you
are in.

best of luck

    Bookmark   February 23, 2012 at 10:56AM
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