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Chimney leak

Montanaman's picture

After a snowfall of about 2 " I noticed one brick in the center of my chimney that was wet.  It's the only brick that is wet and it is about half way up the chimney and on the inside.  Is this common in the case of a flashing leak around the chimney as it goes into the roof, or a leak in the concrete chimney cap?  There is no spark arrestor or other device that prevents the snow coming down the chimney.  To have the leak restricted to only one central brick seems pretty odd.  Any words of wisdom would be appreciated?

You're going to have to (post #207127, reply #1 of 7)

You're going to have to desribe this chimney a little better.

How old is the house?  Does the chimney run up the outside of the house, or is it on the inside of the house?

You say the wet brick is "halfway up the chimney and on the inside" -- does this mean that the wet spot is inside the house, or just on the part of the chimney facing the house or what?

Is the wet spot, as you kind of hint at, some distance below the roof?  How far?

Note that 2" of snow amounts to maybe 1/4" of water -- not very much -- you've probably had rainfalls much heavier than that in recent months.  If the snow caused this at all it's likely because snow pooled up at the joint between chimney and roof.  This problem would be more likely on the "upslope" side than on the "downslope" side.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

The house is 1970's vintage. (post #207127, reply #3 of 7)

The house is 1970's vintage.  The chimney runs up the outside of the house. The wet spot is inside and about 3 feet from the ceiling.  

It occured to me last night that there is a blower for the insert that is housed externally.  I haven't had daylight enough to tell if the blower housing and the wet brick are at the same level and opposite eachother, but if they are I think I will have found the culprit.

Montana (post #207127, reply #4 of 7)

Any black roof goop anywhere on that blower or other penetrations/flashings to the chimney?

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Remodeling Contractor just outside the Glass City.


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Montana (post #207127, reply #2 of 7)

How many flues in the chimney?

If there's an attic space, did you look up there yet?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


There are two flues and there (post #207127, reply #5 of 7)

There are two flues and there is a cathederal ceiling where the chimney is with a very tight attic space.  I determined that the external blower is lower than the leak so I have pretty much concluded that it's coming from the roof. 

It's possible the leak is in (post #207127, reply #6 of 7)

It's possible the leak is in the cap, and water is leaking down the outside of the flue liners (but inside the chimney brick).


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Montana (post #207127, reply #7 of 7)

If the leak is in the vicinity of the space between the two flues (or to either side of where a bricks width divides the two flue liner areas-could be the cap or a gap between the flue and crown.  This concrete cap should have a space between it and the flue liner-packed with a non flamable "rope", then caulked to just above the top of the crown/flue.

Constant fluctuation in temp will erode the concrete next to the flue, that's why the gap, backer and caulk.

Then of course, could be at the roof/chimney flashing.

or perhaps siding to brick if the chimney runs up the outside of the house.

Hopefully you have no black roof goop up there, worst fix possible for a chimney.  Almost guarantees later failure along with future problems finding the real source.

 

If water comes down the inside of the flue, there's a possibility that there's a crack or space in the flue that allows water to get between it and the brick.  It finds a place to collect and appears in the middle of nowhere.

This is not good and potentially unsafe.  Exhaust gases (smoke) and potentially small burning embers floating up the flue might find there way where you don't want them.

 

best of luck.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/