How to extend exterior triple wall chimney stove pipe?

Jon Curl

New Member
Mar 8, 2019
7
Midland, MI
Hi everyone. My family just moved to Michigan after 20+ years in Los Angeles, CA and we're having an issue in our new home with our wood burning stove chimney height being a little too short. Luckily I went on the roof and cleaned the downstairs stove's chimney before a big storm knocked out power and we were able to use it for heat during that time. However, when it snows heavy the snow and ice can collect between the exterior metal stove pipe chimney and our brick chimney stack, restricting and clogging the cap. After a big snow storm I tired using the stove again and it backed up inside the house setting off the smoke and co2 alarms! Being at the same level as the brick, the metal chimney also causes soot to collect on the brick. I've included some photos of the scenario.

I would like to extend the existing 8 inch triple wall exterior stove pipe chimney and install a new stainless cap. I know I can fit a piece of slip in single wall 8 inch round x 12 in. long stove pipe and new cap, but I'm afraid water will then collect inside the triple wall pipe. Our existing cap has a skirt that covers the triple wall openings, but I can't seem to find a similar cap. Even if I did, single wall would still leave the openings exposed. Furthermore, I don't think having a single wall stove pipe extension is code on a roof? I can't seem to find any triple wall extensions to get this done.
Does anybody here know the proper way to extend this 8 inch exterior chimney about a foot and where I can find the appropriate parts? Any advice would be greatly appreciated!
 

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webby3650

Master of Fire
Sep 2, 2008
10,974
Indiana
That’s some old pipe. It’s only rated for 1700 degrees most likely, the current standard is 2100 degrees. @sticks would be able to identify the brand I bet.
 

Jon Curl

New Member
Mar 8, 2019
7
Midland, MI
Yeah it's old. I wasn't aware of the heat ratings, thanks. I'm sure the EPDM rubber roofing wrapped around it isn't good either! I was thinking maybe the pipe is older Duravent, but I can't even find any new production Class A Duravent products to connect together. Is it not possible to extend any Class A pipe? It doesn't appear to have a twist-lock mechanism anywhere, just a single dimpled ring. I'm hoping to fix this scenario myself, as we're pretty strapped for cash after the move, but I just don't know enough. I haven't even seen winter in 20+ years! Hoping someone here will have experience with this type of situation.

I just saw that the National Fire Protection Association Standard #211 states: “Chimneys shall extend at least three feet above the highest point where it passes through the roof of a building, and at least two feet higher than any portion of a building within ten feet.” So, I'm going to need a 24" section, not 12".
 

Ludlow

Minister of Fire
Jun 4, 2018
1,423
PA
Is it wrapped with asbestos blanket?
 

Hogwildz

Minister of Fire
The base flashing is pretty badly done.
 

Jon Curl

New Member
Mar 8, 2019
7
Midland, MI
You must mean around the brick chimney? I agree. I can't even see the flashing on the Class A, as it's under EPDM. I think the whole brick chimney needs to able cleaned, mortar tucked/repaired, and sealed in the spring. Probably just going to leave the base flashing alone though.
 

Ashful

Minister of Fire
Mar 7, 2012
15,715
Philadelphia
Lots of problems. What about some solutions, guys?
 

spudman99

Feeling the Heat
Jan 26, 2018
340
Yardley, PA
If its temporary, can you get another triple wall cap like you have, cut the top part off leaving the collar section. Use that to cover the existing triple wall and then insert the single wall extension inside and screw in 3 places. Seal the joint with hi temp silicone. Put new 8" cap on and secure this fabrication to the existing triple section protrusion on your roof?
 

Ludlow

Minister of Fire
Jun 4, 2018
1,423
PA
That EPDM cant touch the pipe like it does now. Right?
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,067
South Puget Sound, WA
The proper way to fix this is to remove the current pipe, not extend it. Replace it with a good class A pipe and flat roof flashing. If this is for a wood stove and only 6" ID class A chimney is required, consider that as the replacement chimney pipe.
 

Jon Curl

New Member
Mar 8, 2019
7
Midland, MI
That's actually a really good temporary solution to get us through the rest of the season. Thank you very much!

I just went up again today to take a look and things and not only is there creosote collecting on the brick, which is only a few inches away, the creosote build up on the cap and flue is pretty bad for burning well seasoned wood. I think that old triple wall air cooled pipe may be cooling things a little too well? As begreen said, it looks like the only proper fix is to replace the whole chimney with new class A. This chimney is for a MALM Imperial Carousel which requires 8 inch ID pipe per manufacturer instructions. It's actually very efficient for a 1960's fireplace and I'm not going to replace it with a newer unit or convert it to gas. I've included a pic. It's a groovy unit and the fire swirls as it burns, but the drywall ceiling that close is NOT code. I'm not sure what to do about that??? Above the drywall it actually goes in to a ceiling support, then through a portion of the brick chimney stack.

I'd like to actually re-do the entire chimney run myself with new ClassA S6210 or S627 rated pipe with stainless outside. The problem is that I don't know if I can re-use the existing ceiling support and just retrofit newer pipe. I'm a DIY kinda guy, but have no experience with chimneys. Do you think I should replace the entire chimney myself? If not do you know anyone reputable in the Midland, MI I could hire? I work with germanium transistors which require room temp. to function properly and this is currently the only way to get my office up to room temp in the winter.

What would you do if you had this in your house?
 

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armanidog

Burning Hunk
Jan 8, 2017
197
Northeast Georgia
That's actually a really good temporary solution to get us through the rest of the season. Thank you very much!

I just went up again today to take a look and things and not only is there creosote collecting on the brick, which is only a few inches away, the creosote build up on the cap and flue is pretty bad for burning well seasoned wood. I think that old triple wall air cooled pipe may be cooling things a little too well? As begreen said, it looks like the only proper fix is to replace the whole chimney with new class A. This chimney is for a MALM Imperial Carousel which requires 8 inch ID pipe per manufacturer instructions. It's actually very efficient for a 1960's fireplace and I'm not going to replace it with a newer unit or convert it to gas. I've included a pic. It's a groovy unit and the fire swirls as it burns, but the drywall ceiling that close is NOT code. I'm not sure what to do about that??? Above the drywall it actually goes in to a ceiling support, then through a portion of the brick chimney stack.

I'd like to actually re-do the entire chimney run myself with new ClassA S6210 or S627 rated pipe with stainless outside. The problem is that I don't know if I can re-use the existing ceiling support and just retrofit newer pipe. I'm a DIY kinda guy, but have no experience with chimneys. Do you think I should replace the entire chimney myself? If not do you know anyone reputable in the Midland, MI I could hire? I work with germanium transistors which require room temp. to function properly and this is currently the only way to get my office up to room temp in the winter.

What would you do if you had this in your house?
I'd keep it.
You need 36 inches clearance unless you have a heat shield. Does the fireplace top have a heat shield built in?
"HOW FAR SHOULD A WOOD STOVE BE FROM AN UNPROTECTED WALL OR COMBUSTIBLE MATERIAL?
The standard clearance for appliances installed in rooms which are large in comparison to the size of the appliance is 36 inches from the top, sizes, back or front of the appliance. Otherwise, install according to the manufacturer's instructions."

http://nasdonline.org/1248/d001052/wood-stove-installation-and-operation.html


https://www.rockfordchimneysupply.com/blog/clearances_to_combustible_materials/
 

Jon Curl

New Member
Mar 8, 2019
7
Midland, MI
I'd keep it.
You need 36 inches clearance unless you have a heat shield. Does the fireplace top have a heat shield built in?
"HOW FAR SHOULD A WOOD STOVE BE FROM AN UNPROTECTED WALL OR COMBUSTIBLE MATERIAL?
The standard clearance for appliances installed in rooms which are large in comparison to the size of the appliance is 36 inches from the top, sizes, back or front of the appliance. Otherwise, install according to the manufacturer's instructions."

http://nasdonline.org/1248/d001052/wood-stove-installation-and-operation.html
Ok, thanks. It's a wacky unit. I like it and want to keep it, but need to make sure it's safe. I think it does have what qualifies as a heat shield of sorts because they still manufacture the same unit in CA and the current factory instructions require only 24" clearance.
 

Ashful

Minister of Fire
Mar 7, 2012
15,715
Philadelphia
That is a pretty slick fireplace. I love the 1960's feel of it.

Paging @bholler on the chimney questions, but I'm hoping he doesn't tell you that rig has to go!
 
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