Class A Chimney Install on New Construction

[Lancer10]

Hi,
I am constructing a new build this spring and looking for advise on an install of 2 class A chimney pipes in 1 chase. The house will be a single story ranch on a full basement. I am planning to have a jotul oslo freestanding wood stove in my great room sitting on a raised hearth with another wood stove in the basement below in the same location. Chase would all be located inside the building envelope, starting in the great room and extending through the roof line at the peak. Wood framed, wrapped in durarock, then faced using real 1" veneer stone. I would like to keep both pipes vertical without any offsets if possible. My initial design was to use ceiling support boxes and Firestop Joist Shields to go from the basement ceiling through the roofline. So starting both chimneys in the basement ceiling/floor joist aera, supporting the weight using the support boxes, through the floor joists and entering the chase on the main level. The main floor stove would connect in a T but the clean out cap would be moved to the basement ceiling- lower part of the floor joists to be terminated there. Basically not being visible from the basement (hidden in the ceiling) until you need to clean the pipe. I am curious how much space must be left between the two pipes. If you have any pics to share of a simialr install - specifically where both pipes begin would be great. Also, any feedback on running both stoves at the same time and having 1 pipe backdraft off the other. I see most are terminated at different elevations which seems like a good idea vs having them come out evenly. Below is the design that i am trying to emulate but using a freestanding stove vs an insert. Thanks for help.

 

[begreen]

There will need to be a firestop for the basement chimney at the basement ceiling level. This could be the chimney support box. Don't crowd the two chimneys. The chimney pipes need to be far enough apart from each other for their caps to clear at the top of the chase. A tee bracket could support the first floor chimney pipe at the tee.

 

[stovelark]

As you mentioned too, having the pipes up top different heights should take care of any interaction issues. Nice looking setup to be. Let us see the finished product please! Stay warm.

 

[all night moe]

This may warrant some noting? @begreen @bholler

How long does Class A last? Do cheaper grades need replacement before a quality system like Excel? That would be an awful task with the involved chase the OP is planning. I will be doing an exterior chase myself at some point faced with bedrock. I had already planned on using Excel.

 

[bholler]

This may warrant some noting? @begreen @bholler

How long does Class A last? Do cheaper grades need replacement before a quality system like Excel? That would be an awful task with the involved chase the OP is planning. I will be doing an exterior chase myself at some point faced with bedrock. I had already planned on using Excel.

I would avoid any using 430 inner wall. Other than that the main difference is allowing for differential expansion between the inner and outer walls. The higher end stuff is generally better in that respect which means they deal with chimney fires better.

 

[all night moe]

I would avoid any using 430 inner wall. Other than that the main difference is allowing for differential expansion between the inner and outer walls. The higher end stuff is generally better in that respect which means they deal with chimney fires better.

Good to know. Thank you.