Hi,

Had some chimney work done today. After reading some chimney construction
wisdom, I asked the guy to leave a small gap, about 1/4" between the cap and
the flue (terra cotta). This gap is to be filled with some flexible
sealant. We made the gap with a piece of cardboard, which will be removed
after the cap mortar sets.

Recently someone mentioned DEFY Chimney crown repair, which would work I'm
sure, but it costs a bundle and I do not need nearly that much.

Can anyone recommend what I could use for this purpose?

Regards,

RichK

"RichK" wrote in message
...
Hi,

Had some chimney work done today. After reading some chimney construction
wisdom, I asked the guy to leave a small gap, about 1/4" between the cap and
the flue (terra cotta). This gap is to be filled with some flexible
sealant. We made the gap with a piece of cardboard, which will be removed
after the cap mortar sets.

Recently someone mentioned DEFY Chimney crown repair, which would work I'm
sure, but it costs a bundle and I do not need nearly that much.

Can anyone recommend what I could use for this purpose?

They sell a high-temp silicone caulk. I've seen it at Lowes and H.D.

Bob

Thanks Bob,

Been to both and have not had any luck finding it. Can't even find it on
the net. Help Line from DAP suggested using their Polyurethane caulk, but
it does not spec temp anywhere. Guy said it's good up 200F, but I'm not so
sure.

Regards,

RichK


"Bob F"

Recently someone mentioned DEFY Chimney crown repair, which would work
I'm
sure, but it costs a bundle and I do not need nearly that much.

Can anyone recommend what I could use for this purpose?

They sell a high-temp silicone caulk. I've seen it at Lowes and H.D.

RichK wrote:
Thanks Bob,

Been to both and have not had any luck finding it. Can't even find it on
the net. Help Line from DAP suggested using their Polyurethane caulk, but
it does not spec temp anywhere. Guy said it's good up 200F, but I'm not so
sure.

Regards,

RichK


"Bob F"

Recently someone mentioned DEFY Chimney crown repair, which would work
I'm
sure, but it costs a bundle and I do not need nearly that much.

Can anyone recommend what I could use for this purpose?
They sell a high-temp silicone caulk. I've seen it at Lowes and H.D.

Virtually any RTV silicone is good to well over 200F.

I don't think there's any chance at all the temperatures at that point
will be a problem for any high quality silicone caulk.

How deep is this crack and is there anything backing it to help fill the
void?

--

"dpb" wrote in message

Virtually any RTV silicone is good to well over 200F.

I don't think there's any chance at all the temperatures at that point
will be a problem for any high quality silicone caulk.

How deep is this crack and is there anything backing it to help fill the
void?

It's not a crack, but a 1/4" (or so) gap, the depth of the crown, left by
the mason, between the flue and the crown. When the cap mortar sets, I want
to fill that space with some flexible sealant.

Some people recommend using this method to prevent crown from cracking.
Sounds good, but now I'm having problems finding something easily available
to use for that purpose. DEFY product is expensive and sold 1gal
quantities.

Regards,

RichK

RichK wrote:
"dpb" wrote in message

Virtually any RTV silicone is good to well over 200F.

I don't think there's any chance at all the temperatures at that point
will be a problem for any high quality silicone caulk.

How deep is this crack and is there anything backing it to help fill the
void?

It's not a crack, but a 1/4" (or so) gap, the depth of the crown, left by
the mason, between the flue and the crown. When the cap mortar sets, I want
to fill that space with some flexible sealant.

Some people recommend using this method to prevent crown from cracking.
Sounds good, but now I'm having problems finding something easily available
to use for that purpose. DEFY product is expensive and sold 1gal
quantities.


Fire rated from DAP...note even here its service rating is 160F
http://www.dap.com/docs/tech/00077364.pdf

DAP Premium Roof and Flashing Sealant
http://www.dap.com/docs/tech/00077348R.pdf
Physical & Chemical Characteristics:
Volatile: Xylene
Solids: 90% minimum
Service Temperature Range: -40°F to +185°F


Note it's rated higher actual temperature than the fire-rated product.

"High temperature" is only used/needed around the actual outlet of a
stove or similar heating source into the exhaust duct or chimney and
will typically be rated at something like 2000F, not 200F.

I've used just ordinary "off-the-shelf" clear adhesive caulk/sealant for
making probes into large diameter pulverized coal feed pipes in power
plants operating w/ air temperatures of roughly 190-200F and had no
problems with them withstanding the positive pressure and temperatures
for weeks.

There's no way the temperatures at the outside of a chimney flue at roof
level are going to approach 200F during weather during which a
fire/furnace will be operating.

I think you're into the way over-specification region here for an
unwarranted concern.

As for the "crack", I understand the gap, I was trying to find out what
was behind the gap to judge the difficulty of filling the gap. If it's
more than 1/4" deep or has no backing I would get some of the gap-filler
material for backing caulking an insert it first.

HTH...

--

"RichK" wrote in
:


"dpb" wrote in message

Virtually any RTV silicone is good to well over 200F.

I don't think there's any chance at all the temperatures at that
point will be a problem for any high quality silicone caulk.

How deep is this crack and is there anything backing it to help fill
the void?

It's not a crack, but a 1/4" (or so) gap, the depth of the crown, left
by the mason, between the flue and the crown.

Yep, last one I did I left 1/4". 5 gal paint sticks from the Borg perfect
size. Also good when 1/4" gap required between flooring and wall.

When the cap mortar
sets, I want to fill that space with some flexible sealant.

Some people recommend using this method to prevent crown from
cracking.

Yep, but more important to keep the flue from cracking because of the
cap. That was my belief.


Sounds good, but now I'm having problems finding something
easily available to use for that purpose. DEFY product is expensive
and sold 1gal quantities.

Just a professional wanna-be here but I've always used polyurethane -
Henry (900?) or one of the PL's. Good stuff while you're up there to
cover/re-cover any exposed roofing nail heads. Doesn't dry out over time
exposed to sunlight like roofing cement.


Regards,

RichK

Thanks Bundy :-)

"Al Bundy"

It's not a crack, but a 1/4" (or so) gap, the depth of the crown, left
by the mason, between the flue and the crown.

Yep, last one I did I left 1/4". 5 gal paint sticks from the Borg perfect
size. Also good when 1/4" gap required between flooring and wall.

Is the gap in the floor to prevent squeaking? Please tell.

Yep, but more important to keep the flue from cracking because of the
cap. That was my belief.

I read about the gap on askbuilder.com. Idea is good, but seems the article
was written purely to advertise DEFY product, which is expensive and easily
available. They answered my e-mail, but failed to recommend anything, which
is pretty self serving.

Just a professional wanna-be here but I've always used polyurethane -
Henry (900?) or one of the PL's. Good stuff while you're up there to
cover/re-cover any exposed roofing nail heads. Doesn't dry out over time
exposed to sunlight like roofing cement.

Yes, picked up a tube of PL Polyurethane Roof & Flashing Sealant. HelpLine
guy from DAP suggested his own polyurethane, but I could not find it
locally.

http://www.dap.com/product_details.aspx?product_id=13

At lowes, IIRC, it was located near the high-temp stove paint.

Bob

"RichK" wrote in message
. ..
Thanks Bob,

Been to both and have not had any luck finding it. Can't even find it on
the net. Help Line from DAP suggested using their Polyurethane caulk, but
it does not spec temp anywhere. Guy said it's good up 200F, but I'm not so
sure.

Regards,

RichK


"Bob F"

Recently someone mentioned DEFY Chimney crown repair, which would work
I'm
sure, but it costs a bundle and I do not need nearly that much.

Can anyone recommend what I could use for this purpose?

They sell a high-temp silicone caulk. I've seen it at Lowes and H.D.

"RichK" wrote in
:

Thanks Bundy :-)

"Al Bundy"

It's not a crack, but a 1/4" (or so) gap, the depth of the crown,
left by the mason, between the flue and the crown.

Yep, last one I did I left 1/4". 5 gal paint sticks from the Borg
perfect size. Also good when 1/4" gap required between flooring and
wall.

Is the gap in the floor to prevent squeaking? Please tell.

Wood product floors. Expansion and contraction to prevent bowing, humps,
buckling, etc. Different gaps for different products.


Yep, but more important to keep the flue from cracking because of the
cap. That was my belief.

I read about the gap on askbuilder.com. Idea is good, but seems the
article was written purely to advertise DEFY product, which is
expensive and easily available. They answered my e-mail, but failed
to recommend anything, which is pretty self serving.

We're all just capitalistic pigs when you come down to it.

Just a professional wanna-be here but I've always used polyurethane -
Henry (900?) or one of the PL's. Good stuff while you're up there to
cover/re-cover any exposed roofing nail heads. Doesn't dry out over
time exposed to sunlight like roofing cement.

Yes, picked up a tube of PL Polyurethane Roof & Flashing Sealant.
HelpLine guy from DAP suggested his own polyurethane, but I could not
find it locally.

http://www.dap.com/product_details.aspx?product_id=13





Al...
Today the painters tool was lonely. No activity. Roofing nailer happy
though