New Construction Help

[Teela Lane Maple Syrup]

I bought a homemade evaporator last year and boiled outside. This year to be a little more efficient, I am building a 12x12 building. Just curious if my chimney should exit thru the roof with a straight shot or if i could put a couple of 90degree elbows and have it exit thru the wall and extend beyond the roof line. Not sure of where to find the thru the roof designs or parts if I need to go that route. Any help would be great.


Teela Lane Maple Syrup
Newbie- First Year-2011
2x6 Homemade Evaporator with preheat pan
30 Trees Tapped 2011, hoping for 100 tapped in 2012
6 Gallons Yeilded 2011

[KenWP]

The extra corners will slow down the draft some what is the biggest problem plus it gets hotter then blazes when you go sideways with it. Also it has to have a bend on the outside to go straight up or you run into problems with wind blowing in the stack and slowing your draft even more.

[Haynes Forest Products]

Holes in the walls or in the roof whats the differance. Up and away is best. If you go out the side you still need to deal with the heat twice thru the wall and then past the eve.

[maple flats]

What size stack? Through the roof is far better. You must protect the wood within 36" of the stack. I will post later and give you some options.

[red maples]

Through the roof is better and since you are making a new a new sugar house why not do it right the first time..ff you are putting a metal roof check with the manufacturer they usually have some sorta chimney adaprt that will fit with the style of metal....that being said you can go through the wall too. you won't have a draft problem but I do recommend a stainless stack especially through that flat spot it will turn a red stack for sure. The stainless will take the heat better but expect it to be a nice copper color by the end of the season!!!

Mine goes straight up and out and is copper colored now, but I had someone visit the sugar house and said boy you must have a paid alot of money for that copper stack.........;)

Depending on your stack size mine is 8" so it was pretty easy to find insulated pipe to go through the roof section. but you can build a box around the stack area sorta like you would do with a sky light and wrap ceramic blanket around the stack and around the roof joists too just be safe.

[Ausable]

Have done it both ways - The double elbow and straight up. I agree with everyone else - straight up is far better. A better draft and hotter fire with straight up.

[maple flats]

For clearances from the stack to wood, you either need to insulate or install layers of metal spaced 1". If you go with the metal, every layer spaced 1" reduces the clearance needed in half (This is by code, I was in the woodstove business back in the 90's) bare single wall stack=36", 1 layer spaced 1"=18", 2 layers spaced 1"=9" and 3 layers spaced 1"=4.5". For insulated, you'll need to get specs on the insulation used. Ceramic might be best choice but vermiculite might be an option. I would not hesitate to make an insulated pipe by building a section with a double wall and a 3" space filled with vermiculite. Then just leave a 1" clearance.
The problem with clearances to close is that the heat from the stack drives out wood gases from the wood. After the wood has completely off gassed you have charcoal and the combustion temp of charcoal is very low and the stack will be at 600-1200 or more. My stack before over fire air (OFA) ran between 750-1100 with some spikes even higher, now with OFA it runs from 500-750 with rare spikes to 850 or so. You have a lot of heat and this heat is hot for long periods of time. Be sure to be safe with your design.

[Flat47]

My rig uses standard 8" pipe and the Metalbestos brand roof jack for their double wall 6" pipe worked perfectly. I got it at the local hardware store. I think there are two to choose from depending on your roof pitch. Fairly inexpensive (around $65) when compared to the big maple dealers.