Off set in stack...

[johnallin]

Didn't want the stack too close to the cupola where it comes out of the top of the roof, so I moved it back one set of rafters.

Now I think I may need to add two 45 degree sections of 10" pipe to keep good clearance from the back wall of the sugarhouse - it's only 5" away from the wall. Have any of you done this and how did it work out for you?

[KenWP]

What have you put on the back wall for fire proofing and you can't have to many bends in the stack or it causes back pressure.

[3rdgen.maple]

You would be okay if your coupla was not directly over your pans so that you have space between the coupla and the stack. Personally I would avoid any bends in the stack. 5 inches is pretty darn close for a stack and if you do not want to move your setupnow extensive fireproofing on that wall would be mandatory.

[Brent]

I'll third the comment the 5" is scary close.

I think if I was doing the offsets I'd try to split the total height into 3 sections or something like that, and make the bends as small an angle as possible. If you can get the adjustable elbows you may be able to make them each 30 degrees or less. This will reduce the back pressure somewhat.

[gmcooper]

Find a way to go without and elbows in the stack. 10" elbows in a heavy enough gauge that they won't disintergrate with all that heat will be very hard to find. I highly doubt you want to see what happens to a 10" elbow that can't handle the heat.

[johnallin]

My thought was to use a 45 degree elbow up at the roof jack and keep the stack away from the wall about 20" or so.

I was thinking of placing some triangular -roof is 12/12 pitch - metal shields at the rafter caps with ceramic blanket all around that area. It's a 10" stack and with 22½" between rafters it's pretty darn close any way you look at it.

Big thing is too keep stack away from the back wall - my issue was if I didn't move it back, the stack would be only 8" away from the cupolla siding which is cedar. In hindsite it would have been easier to shield the back side of the cupolla, but the hole is cut, the roof jack is in place and I need to fireproof the last 12" or so of the stack. Just don't know about supporting the darn thing.

Any thoughts are appreciated...

[Brent]

Shops that sell woodstoves have heat guards to put on stacks. They are half pipes ( 180 deg.) and come with standoffs that separate them from the stack by an inch or so. As the air between the sheild and your stack heats it starts quite an airflow upward. We put a set of these on our Vermont Castings woodstove and the back side of the sheild, closest to the wall, was cool enough to put your hand on it ... briefly. They're not very expensive.

[WESTVIRGINIAMAPLER]

I have all my exposed wood within 30 to 36 inches of the stack covered with 1" of ceramic blanket. It insulates very well and deflects the heat. Over time, 5" clearance will likely catch the building on fire and maybe even the first year.

[johnallin]

Brent,

Thank you, sounds like just what I need as it should alow me to keep the stack straight without worry of support at the elbow. I will start looking for them.

Just wish I gave it a little more thought when I started cutting for the the roof jack and locating the cupolla.....Keep saying to myself, on my next sugarhouse, but then realize that this is going to be it so I better start paying attention.

[3rdgen.maple]

johnallin you know the great thing about holes in the roof is they can be covered up. I know your pain and would be willing to bet that you would be much happier and better off to relocate the coupla and get that stack away from the wall. Yep more time for sure but time is nothing compared to If I only or worse a fire.

[unclebuck]

I also had a problem with distance to the wall (10 inches).The building inspector in my town required me to put concrete board with stand offs from the wall (2 inches) from the back of the evaporator to the ceiling. he also made me put the concrete board on the roof where the stack goes through. had to cut extra 5 inches around the pipe. the biggest problem we had was to nail the shingles to the cement board. this will be our 10th year with this and no fires Knok on wood

[Fred Henderson]

I caught my rafter on fire my first year with 8 inches of clearence and I was using a 10 " stack back then. We threw sap on it to get it out. I then kept a pressure garden sparyer there for the rest of the season. wetting it down every hour that we boiled. After that season was over I did some roof remodeling and now have 24 " of free air all around.

[johnallin]

Fred,
Thanks for your input.
I have now have ceramic blanket and board to work with along with some stainless sheet metal to cover the ceramic. I will cover the rafters with this set up down until I am a good 12" or more away from the stack.

The roof was cut out between the rafters - 22" spacing and down 15" each side. From inside all you can see there is the bottom of the roof jack. The stack goes right through the ridge and fits into a stainless 12/12 pitch roof jack from Leader. As the new sugar house is timber frame, I have no ridge beam to contend with and rafters are 4X6 hemlock. Yea I know 2x4 or 4x6 it's all wood and wood burns, but per the folks at Leader this is the way the roof jack is designed to be installed. I just want to cover all the bases here.