Chimney installation questions...

[mlo1]

One and a half story craftsmsn style home. The 2nd story exterior wall is in-set 5' over the first story where the wood stove will be located beneath. The chimney will basically run up through the cieling of the first story and along side (outside) the 2nd story wall. The chimney will need to go through TJI trusses that are actually sheeted with 3/4" subfloor, through a hip mono-truss soffit area, and up along side the 2nd story wall, then through the 2nd story soffit/truss tails and out the roof 4'.
Seems the typical attachment to support the chimney is a "support box" that mounts between the TJI's. Problem is, the support box "centers" the pipe. For the chimney to line-up with windows, truss tails, etc., the pipe needs to be offset in the 2nd floor TJI cavity. Near fully to one side of the TJI cavity.

Is there a support/mount that will hold 15' of 6" double wall chimney which can mount to the wall inside the mono truss cavity instead of a support box between the TJI floor joists?

How much room is needed between the outside 2nd story wall and the 6" chimney pipe for flashings to be nicely installed and roofing material fitted, on the homes weather exposure side?

I know 2" is minimum double wall pipe clearance, but seems that is in-sufficient for a flashed and correctly roofed exposed opening (no boxed chimney chase). Almost as if the flashing would be right up against the 2nd story wall finish.

I'm ready to roof a new construction home and want this install right from the beggining. The local installers seem to prefer hacking it up after the roofing is applied. As they say "it's always done that way".

Any insight is appreciated, Thanks.

 

[Metal]

The support box is built to maintain the minimum clearance to combustibles. In the case of a box for 6" pipe the box is smaller than the box for a 8" pipe, you just need to frame in a square the size the manufacturer requires (differs by manufacturer) so you could frame it in to one side or the other. By the way, 2" CTC is the MAXIMUM for Class A Pipe, not the minimum. There are companies that have clearances as low as 1.5" for 6" pipe.

 

[mlo1]

Maybe my wording was confusing...The manufacturer is saying I need 2" between the double wall chimney and any combustables. Where the chimney goes through first story roof and up alongside the second story exterior wall (hardieplank), how much of a gap do I need to sufficiently flash and roof around the flashing, for it to be correct and asthetically pleasing?

Seems that 2" (manufacturers minimum clearance) is to small of a gap for this install cenario. I'm trying to figure out how far away from the second story exterior wall I need to be, when making my hole from the first story and through the monotruss soffitt area.

TIA