Does any brand of Class A allow an offset around an eave?

[ericj]

Hi everyone, I've spent dozens of hours reading on the site and have been blessed by your knowledge.

My question: I want to install a woodstove on the first floor and am forced to do a 'through the wall' installation. (The reason is that the main living room is directly above the rec room I'm hoping to install the stove in. The only way I can keep the chimney indoors is to go 'through the wall' into an attached garage -building a chase- and then up through a closet -building another chase- into the attic and through the roof. Either installation requires a 90 degree elbow.) If I run up the outside wall, the chimney will go 21 feet on the gable end and offset around a soffit that extends out 9 inches. Rather than notch the soffit, I'd like to use an offset around it. I know some brands of stainless steel chimney forbid this. Do any allow it? It seems that my local inspector requires me to follow the instructions on whatever product I'm installing. I would like to use the least expensive class A chimney I can. Thanks for your help.

 

[begreen]

Greetings Eric. Major class A pipe makers have a 15 or 30 degree offset elbow that is used in pairs for this type of installation.

Here's an offset installation:
https://www.hearth.com/econtent/index.php/forums/viewthread/51285/

And here's a notched soffit installation: https://www.hearth.com/econtent/index.php/forums/viewthread/52119/

 

[My Oslo heats my home]

Your right with the manufacturers instructions. The inspector will request to see the products manual and review the installation specs. As long as you have followed what is written he will sign off.

Is avoiding the soffit the only way around the stack making it up to it's highest point?

 

[ericj]

My Oslo heats my home: Is avoiding the soffit the only way around the stack making it up to it’s highest point?


I think you're asking if the soffit is the only thing prohibiting the chimney from extending up the house and clearing the roof by the required 3 feet. Yes, just the soffit. There are no windows on that side of the house that I have to dodge.

I understand Supervent does not allow the use of a 30 degree offset on an outside chimney (or a 15 degree for that matter). They require a straight up installation. I'm wondering what brands do allow this 30 degree offset. Thanks

 

[My Oslo heats my home]

Eric, Thanks for understanding my question. I'm not into the reg's on double walled, but I'm sure the rules are simular to that of single walled, that being the restrictions that are caused with offsets and elbows. You may have to research some of the other manufacturers that will allow the app your looking for. Good luck!

 

[begreen]

Selkirk MetalBest pipe:
http://www.northlineexpress.com/multiple_items.asp?cc=6MetalBest
Simpson DuraTech pipe:
http://www.northlineexpress.com/multiple_items.asp?cc=6SPDuratech

 

[DAKSY]

I understand Supervent does not allow the use of a 30 degree offset on an outside chimney (or a 15 degree for that matter). They require a straight up installation.

Where did you hear that? Class A chimney is approved for interior or exterior installations.
The offset can't be more than 30 degrees, but they're allowed to be installed anywhere
except where they pass thru a ceiling or roof. All those penetrations must be vertical.

 

[ericj]

The Selkirk installation guide says not to offset around a soffit because the elbow can't hold the weight of the offset. (You CAN offset around a window however. I'm not sure why. Maybe because a support strap can be used above the offset around a window whereas after an offset around a soffit the chimney is freestanding in the air.) Below is a copy of their FAQs found at http://www.selkirkcorp.com/supervent/lowes/faq.asp

I wanted to use Supervent because it is the cheapest, by a lot.

Q. My "Through-the-Roof" installation cannot go straight up, what should I do?

A. You will need to offset your chimney using elbows. Elbows are available in 15° and 30° offsets.

Q. I have 6 ft of chimney above my roof. Do I need additional support?

A. A Universal Roof Guy Kit must be use when chimney extends 5 ft or more above the roofline.

Q. I have an overhang in the way of my Chimney, as it goes up the side wall. How do I get around it?

A. You must cut through the soffit (overhang). Use a Roof Flashing above and a Finishing Plate below where you have cut through the roof. Never offset an exterior Chimney - there is not enough support for the weight above the elbow.

 

[begreen]

Give them a call. They sell locking bands to make the elbow offset act like one unit. If the offset is done a couple feet below the soffit and then supported above the offset, the weight supported is the same, no?

 

[jtp10181]

When you do an offset you are probably supposed to use a support strap with like 3 metal straps coming off and attach to nearby framing. Obviously this is not possible outside.

The wall brackets are not made to support the weight of a chimney, only to stabilize it. The Tee support holds all the weight.

The only "support" you could offer above the offset would be a wall bracket attached to the fascia, which will hold some weight but I do not believe they are tested or rated to support the chimney weight.