Leaky Roof or Condensation from furnace?


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Old 02-19-06, 05:57 PM
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Leaky Roof or Condensation from furnace?

I live in Minnesota where it was recently -29. I have an icicle inside my attic right next to the chimney and some water on the attic floor. My roof was recently redone and leaked occasionaly when it rained (right around the chimney) the roofer came to fix it and it shed water well this summer (no leaks). As of this winter I have a water problem again. (Standing snow?)

The roofer said he'd tear it apart and redo around the chimney but I am wondering if condensation from the furnace could be the culprit. I don't think I have a liner in the chimney and both the water heater and the furnace vent out the chimney. Is this even a remote possibilty?

Thanks for any help!
 
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Old 02-19-06, 07:14 PM
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sounds like a roof leak to me

Welcome, Eaton.

I am wondering if condensation from the furnace could be the culprit.
Only if there is a gap in the mortar.
 
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Old 02-19-06, 11:10 PM
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Yes, it could be condensation. The condensed water can soak the moartar, the brick or concrete block and soak through. As for the possibility of it being a roof leak, at -29F, there is no rain and little chance of melting snow. Do you have a cap on the top of the chimney? That can contribute to the condensation problem.
 
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Old 02-20-06, 02:11 AM
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Originally Posted by fixitron
The condensed water can soak the mortar, the brick or concrete block and soak through. As for the possibility of it being a roof leak, at -29F, there is no rain and little chance of melting snow.
One can say the same about bricks and mortar. Liquid water can't penetrate at -29F. If the chimney is warm enough to allow water to pass through, then it is warm enough to melt the snow that is touching it.

It is not -29F there all the time. An icicle strongly suggests that the water originates where the sun is shining and runs down inside where it is colder.
The mortar would have to be pretty porous to allow enough water through to form an icicle. I'm just looking at the most likely cause.

The sun can easily melt snow against bricks when the air temperature is 15F.
 
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Old 02-20-06, 07:57 PM
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eaton

Both Fixitron & Bodine have valid points but I would tend to think along the lines of a roof leak. Something I think you should strongly consider is an insulated metal liner for your chimney. Even if your chimney has a masonry liner you can get a lot of condensation in the part of the chimney in the attic.
 
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Old 02-20-06, 11:41 PM
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A nice new condensing furnace would probably be as effective as the chimney liner.
If an update to the furnace is planned, fixing the chimney is not my idea of a good investment.
Brick chimneys and roofs do not seem to get along very well.
Eliminating the chimney will eventually eliminate the roof leak.
 
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Old 03-13-06, 05:48 PM
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Thanks you guys!

Well-

Over the past few weeks we've had snow and rain--yet no leaks. So now I'm pretty much thinking it must be excess condensation when the furnace runs constantly.

As bolide mentioned, I seems to make more sense to get a higher efficiency furnace vented out the side and knock off the bricks--maybe use them for a patio...

So now I'm getting furnace estimates....

Sounds as if Armstrong would be good enough, installed by a pro.

Thanks again!
 

Last edited by eaton; 03-13-06 at 06:02 PM.
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Old 03-13-06, 06:39 PM
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> now I'm pretty much thinking it must be excess condensation when the furnace runs constantly.

Did you rule out moist air from the interior leaking from the house around the chimney up into the attic and condensing on the underside of the roof?

This also could form ice only when very cold.


> knock off the bricks--maybe use them for a patio...

If you make sure your plenum is attached to the ceiling and remove your old furnace yourself this summer and set it aside, you can open a big hole in the base of the chimney.

Dropping the bricks down the inside is dusty and messy, but fairly safe versus throwing them off the roof. Wear a breathing mask and eye protection regardless as there will be a draft up the chimney.

Expect half the bricks to break.


> Sounds as if Armstrong would be good enough, installed by a pro.
Sounds good.
 
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Old 03-14-06, 08:10 PM
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Geez

well the furnace guy came over today... He said the leak must be from the roof. He didn't think an unlined chimney could produce that much condensation to make the icicle as big as I described...

so I guess the condensation querry remains.

Just wanted to post this so no one with a similar problem felt I had solved the problem...That is discovered the reason for the leak.

I'm solving the problem the old fashioned way...throwing money its way
 
 

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