On Thu, 7 Apr 2011 04:40:52 +0000 (UTC), Aaron FIsher
wrote:

On Wed, 06 Apr 2011 15:44:07 -0700, Joe wrote:
If you get one made with these modified galvanized
materials it should last for many years.

The old one was (apparently) galvanized sheet metal because I don't see
any rust but it was very heavy lifting off the chimney (which sticks up
off the roof by at least four feet).

The problem is high wind. We get 100mph winds here on the mountain facing
the ocean. Over time, the winds caved in the structure.

I'll take a measurement and post that later. I think it needs better
cross bracing against the wind.

Of course that will make it a little heavier. REading all your posts,
I'm amazed you got it down.

But, what I'm trying to find out is whether it's actually necessary. It's
going to rain tomorrow but when it's dry, I'll try to go up and snap a
picture or three to post so you can see what I'm talking about.

Thanks.

You don't say what you burn that needs a chimney, or what the chimneys
are made of.

AFAIK the purpose of a chimney cap is to keep critters and rain out.
Even the low sulfer oil that I burn in my furnace has some sulfer and
soot inside the chimney can turn to sulfuric acid when it mixes with
water. I think it still takes a long time to eat through a stainless
steel chimney. Are their other combinations that might cause
problems, I don't know. Maybe if it rains hard enough it can put out
the fire...pretty much kidding. I doubt that.

As to critters, that includes squirrels, birds, raccoons?, and
pterodactyls.