Big day draws near

[MedicineMan4040]

Next Tuesday the wood stove flu installer comes to cut holes in the floors and roof!
My house is 3 stories, the 3rd floor is Cape Cod style with knee walls.
In my case the knee walls and the floor inside the knee wall is not insulated, the roof is insulated.
So when my flue (Selkirk Class A double wall) passes through the roof it will be identical in many ways
to a flu going through a cathedral ceiling and out into open air.

My question, knowing I need to maintain 2 inch clearance even as the flu passes through the roof is about
condensation.
It seems like only thin flashing metal will be between conditioned (warm moist air) space and next week between
1-5F outside air.
Seems like condensation is gauranteed (except when the stove is running of course).

But Selkirk makes a product called SUSI I'm just now discovering via Google-

Selkirk Universal Shielding Insulation - SUSI - 200001

Selkirk Universal Shielding Insulation - SUSI - Optional insulation for use with the Support Box, Attic Insulation Shield and Insulated Wall Thimble. The SUSI protects building material - NorthlineExpress.com

www.northlineexpress.com

Is this what I need for insulating/preventing condensation where the flu will actually exit the envelope?

Thanks for any clues/suggestions!

 

[begreen]

Normally the chimney pipe would just go straight up through an oval hole in the roof with roof flashing cone above. This is because the chimney support is down below. A cathedral ceiling support box can't be used because it is not designed to connect to chimney pipe below it. I haven't heard of stuffing the underside of the flashing cone with insulation.

 

[MedicineMan4040]

So, chimney support is either at the roof=cathedral ceiling support or in the floor above the wood stove.
Well I'm tired of fretting over it. Wood stove installer has done well over a hundred wood stove installs (so
he says). I'll just relax and see how it all transpires.
THEN I have to deal with the wife and the chase as it passes through her living room haha!
As always thanks Bgreen.

 

[begreen]

Stove pipe, even if double-walled, can not pass through a wall or ceiling. It must be chimney pipe after that point.

 

[ctreitzell]

Stove pipe, even if double-walled, can not pass through a wall or ceiling. It must be chimney pipe after that point.

this is very easily mixed up when manufacturers sell "chimney systems"

 

[begreen]

The biggest mixup we see comes from both stove pipe and chimney pipe being called double-wall. One is double-walled with and air gap and the other is double-walled with insulation. Further confusion happens because there is also triple-walled chimney and some think that 3 must be better than 2. It's not.

 

[ctreitzell]

The biggest mixup we see comes from both stove pipe and chimney pipe being called double-wall. One is double-walled with and air gap and the other is double-walled with insulation. Further confusion happens because there is also triple-walled chimney and some think that 3 must be better than 2. It's not.

yes, triple wall I first heard explained by the guy who does the embers videos...too cool equals creosote and condensation IIRC

thanks for clearing it up from stove pipe to chimney pipe

 

[webby3650]

The SUSI part you shared is for that purpose. In colder climates it’s added to the support box or in the insulation shield. We use them to stuff flashings and wrap pipe at the roof deck if they are spray foaming. Actually we used to. It’s nothing more than fiberglass. We started using 1” ceramic wool, because we have it around already.

 

[MedicineMan4040]

Webby thanks again. I'd think I'm in a cold climate. Last year we hit -8F for 2 days, but that was at the
other house; here where the chimney is to be installed it was a balmy 4F.