Chimney water leak

[fire_man]

We had a 2" rain storm last week and I had water dripping inside the fireplace where there is a woodstove install. I have an insulated 6" SS pipe inside a clay liner normally capped like in the photo.The day before the storm I removed the steel cap covering the top of the clay liner so that I could extend the flue a couple feet for better draft. The extension does have a cap.

One leak was from the lintel plate but no bricks above were wet. The other leak was from the back edge of the blockoff plate where it mounts to the rear of the firebox. There was NO evidence the leak was due to rain entering the clay flue liner since there were no drips along the 6" ss pipe passing thru the blockoff plate.

The only entry point I can think of was where the clay liner meets with the crown. Can that be sealed with regular silicon calk? Any ideas where else the leak can come from? There is a lot of exposed chimney crown since it's a 6' x 3' chimney with a single flue. Funny how it happened right after I removed the cap but we have been in a drought for months.

I'm stumped.

 

[Smock2015]

If you got 2 inches of rain it could have been coming through the bricks from the ground but that depends where the fireplace is... happened to my FIL but his fireplace is in a basement

 

[ccmac]

Try an elastomeric (sp) coating on your crown. I used something called "Duck Coat". It is essentially rubberized paint. It flows into all the cracks and bonds very well to stone, concrete, brick, ect.... I would also recommend "Chimney Saver" be applied to the chimney bricks. Just good insurance against water penetration.

 

[begreen]

It would be good to do a close inspection of the crown and cap plate. Bring a camera with you to get some good pics.

 

[fire_man]

Thanks for the replies.

I have routinely ( every 3-4 years) sealed the exterior brick with a siloxane based water repellant due to porous brick problems. But that problem previously resulted in wet bricks on the inside of the house far above the fireplace opening. The current leak is dripping INSIDE the fireplace opening. I will see if I can get some pictures of the crown.

 

[begreen]

Was the top plate siliconed to the clay flue liner?

 

[fire_man]

The top plate was definitely siliconed to the clay liner. I watched the chimney sweep do it.

I think I confirmed the source of the leak. I squirted a 32 oz bottle of water at the interface between the clay liner and the crown, and the water disappeared. It was hard to see an actual "leak" but the water vanished. To make matters worse, the bottom frame of the steel fence that supports the missing cap traps water between the 1" protrusion of clay liner and the frame which is cemented to the chimney crown.

The only solutions are A) calk the clay liner interface to the crown or B) fabricate another cap that the 6" SS Pipe Extension fits thru so that water sheds past the cage. I think the calk is just a bandaide that will not hold up, especially since water gets trapped as I said.

I would like to get a better picture of the setup that shows the top plate and clay liner - maybe tomorrow while I'm outside smoking some ribs!

 

[Woodfarmer1]

We had a 2" rain storm last week and I had water dripping inside the fireplace where there is a woodstove install. I have an insulated 6" SS pipe inside a clay liner normally capped like in the photo.The day before the storm I removed the steel cap covering the top of the clay liner so that I could extend the flue a couple feet for better draft. The extension does have a cap.

One leak was from the lintel plate but no bricks above were wet. The other leak was from the back edge of the blockoff plate where it mounts to the rear of the firebox. There was NO evidence the leak was due to rain entering the clay flue liner since there were no drips along the 6" ss pipe passing thru the blockoff plate.

The only entry point I can think of was where the clay liner meets with the crown. Can that be sealed with regular silicon calk? Any ideas where else the leak can come from? There is a lot of exposed chimney crown since it's a 6' x 3' chimney with a single flue. Funny how it happened right after I removed the cap but we have been in a drought for months.

I'm stumped.

So you removed the chimney cap and wonder why you have a leak?

 

[fire_man]

So you removed the chimney cap and wonder why you have a leak?

A. It did not leak the previous two burning seasons with the cap removed.
B. You should not require a cap to prevent a leak with the current setup.