George and Len both described things the way that I understand them, too.

This latest is pretty good advice, in my book . . . because in spite of what
many roofers and bricklayers would call the "cap" (that is, the cement "hat"
which surrounds the flue and shields the bricks from rain), there are many
others including roofers and masons who might just call the "cap" what I
would call the "flue screen" or "squirrel preventer". So, if you ask the
HVAC guy which one he had in mind, and he tells you, then you know! All
discussion here, while interesting, would at least be unlikely to cause you
problems with fire safety or spending money on something not necessary.

BTW, if the masonry cap on your chimney needs to be replaced, you should
really get a mason or chimney sweep to do it. They should know which parts
of the masonry need a strong mix (the "cap") and which should have a weak
mix ("tuckpointing" between the bricks) to ensure that your bricks are
properly protected from moisture. It would not be uncommon for the masonry
cap to need repair or replacement after 45 years, especially if minor damage
had not been repaired during that time. If it does need it, then get it
done for your safety. You don't want to mess with flue gasses improperly
getting into your living space.

Steve Johnson

"George E. Cawthon" wrote in message
...


LenS wrote:

On Fri, 26 Dec 2003 06:44:05 GMT, "George E. Cawthon"
wrote:

I'm with you. A screen on the flue is not a chimney cap, it
is exactly what you said. However, erosion of the chimney
cap in 5 years, is possible only if the chimney were
improperly built.

We've lived in the house for just over 5 years but I don't know how
long the chimney cap was there. We're the third owners of a 45 year
old house.

However, who knows what the HVAC guy was talking about.
What he found certainly wasn't due to failure of the chimney
cap, it was due to stuff falling into the flue.

Um...I thought the cap was to keep stuff out of the chimney so it
won't drop into the flue (assuming the flue is the exhaust for
combustion byproducts from the furnace.] I'm really not too bright on
this stuff.

Anyway, since I'm not inclined to climb onto the roof to find out
what's in the chimney (my across-the-street-neighbor broke his hip
falling from his roof) I'll just have to hire someone trustworthy to
do it.

Thanks to you and all the others for the comments and help.

-Len

Hey, you could call the guy and find out what he really
meant. Masons call the mortar at the top of the chimney, a
cap, that is, it caps the bricks. But people don't use
words very precisely and like to make up their own
definitions. Makers of metal chimenys call the attachment
on top a weather cap, a cap, or a screen,or maybe something
else. Brick chimneys with clay flues used for fireplaces
often don't have a weather cap or screen. But if it is for
a furnaces I would certainly want a screen or weather cap at
the top.