Corner install of wood stove on ground floor running pipe through multiple floors

[azor]

Hello! I'm new here and am hoping someone can help me with a few questions about a wood stove pipe coming from a corner install on the main floor (new construction just started building). Originally, I had thought wouldn't it be neat to get a little heat from the pipe coming through the floor into my master bathroom right in the corner where my bathtub would be located. But, recently our local wood stove guy told me that in Maryland after you run a double walled pipe through a 12" ceiling support box you must then switch to class A pipe and it must be enclosed in a framed structure with a minimum clearance between the outer pipe and inner framing of 2". He's saying all together the exterior of the enclosure will be 18" square because of the width of the 2 x 4s, etc.

First: Is there no type of pipe that I can use in my bathroom that wouldn't require an enclosure after it clears the floor and tub until it has to be put through another 12 ceiling support box before going into the attic? I actually wanted the look of an exposed pipe in the corner of the bathroom....

Second: Why does the enclosure have to be 18" wide? Can't we use something else to attach dry wall to other than 2 x 4's? Like maybe a metal frame? It's important the enclosure, if truly required, be as small as possible as there isn't that much room before the tub starts.

Third: This has to do with the pipe after it gets into the attic - if I run it straight up and through the roof, it will be a horribly tall and ugly chimney. I have to shift the pipe towards the ridge of the gable roof to decrease the size of the chimney. So, I will need to add two bends to get it where we need it. My wood stove guy is saying that will have a bad effect on the draft and built up creosote etc. But, that pipe is going to be over 35 feet long! I can't imagine draft being a problem! I had an old VC stove in the basement of my first home and it had 2, 45 degree angles going up about 30 feet and the draft was awesome.

Any advice would be appreciated - thanks!

 

[kennyp2339]

Answering your questions in order, short and sweet method -
1. Heat with the stove not the chimney
2. Installer seems fairly knowledgeable and into following building codes
3. So the OD of the class A still requires 2" all around from combustibles, add all that together and a framed chase of 18" seems legit
4. Installer is kind of right with the straight up method, but your also kind of correct with using elbows to off set, remember the 3-2-10ft rule here, chimney height - 2ft higher when on the ridge or 3ft higher then anything within a radius of 10ft, I think with such a long run within the building envelope a couple offsets wont have that much of an effect on draft, or cooling flue gasses to bad, just make sure the offsets are strapped correctly and when cleaning the chimney extra care is used in that section.

 

[bholler]

You will need 12" of space inside the chase for most chimneys. That is the 8" od of the chimney plus 2" on all sides. Yes you could use steel studs to frame it and just have the thickness of the drywall outside that 12".

And with the height you have I doubt draft will be an issue if you offset