Fireplaces, Heating Stoves, Flues and Chimneys - need better chimney rain cap

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View Full Version : need better chimney rain cap


xiphias
04-23-07, 11:09 AM
Situation: wood stove in existing fireplace, 17x17 stainless cap on existing chimney with 12x12 clay liner.

Problem: rain comes down chimney when it's windy (around here, that's pretty often). Sometimes quite a bit of water.

Solution: ?

Options being considered thus far:

a) Lyemance damper under existing cap. Bore hole through damper pan for cable/chain assembly so it mounts the same as it would without the wood stove present.

b) add copper wind diverter/flashing around existing cap.

c) something else?

Thanks for any suggestions/insight.


Concretemasonry
04-23-07, 11:33 AM
A photo would help.

What is the condition of the "crown" of the chimney? - the material on the brick that slopes away from the flues.

How high above the chimney does the rain cap sit?

Dick

twelvepole
04-23-07, 02:21 PM
Inspect mortar cap on top of chimney for cracks or separation between mortar cap and flue extending up through mortar cap. Cracks can be sealed with high temperature sealant. If you can not access top of chimney, call a chimney professional. Also inspect for open mortar joints or cracked brick where water can enter. Even with a chimney cap, you can get occasional water down the flue from wind driven rain under the chimney cap.


xiphias
04-23-07, 03:50 PM
Thanks for input. Here's a pic. (The big ladder is at a friend's house, so no direct access to chimney at the moment.)

http://i77.photobucket.com/albums/j50/xiphias1758/chimney.jpg

The clay liner sticks above the crown about 2-3".

A local chimney pro (CSIA certified; good guy; been around for decades) has been sweeping and inspecting this chimney for 7 years. Crown and mortar, bricks are in good condition.

Rain without wind (although rare) is not a problem, hence he/we thinks it's not leaking through the crown or bricks. It's coming down the flue.

Thanks.

twelvepole
04-23-07, 04:16 PM
If everything is intact, then it sounds like wind driven rain coming down the flue. This is not uncommon. Perhaps your chimney pro friend can suggest an alternative chimney cap that prevents this problem. There are specialty caps that prevent wind driven rain problems--

http://www.volko.com/superdowndraftchimneycap.htm