Cupola Question

[optionguru]

In the process of building my 14x16 sugar shack and I'm planning on putting my evaporator a little off center and towards the back of the shack to give more socializing space. My cupola will still be along the top ridge of the roof but should it favor the back of the shack? Also should it be oversized since the steam will not be going straight up to it?

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Also, the walls are going to be about 10' does this effect anything?

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[PerryW]

Yes, I would try to center the cupola over the pan as much as possible.

re 10 foot walls: I was told that if the walls are too tall, you may get more condensation before the steam makes it out of the cupola. Especially with metal roofing.

[wnybassman]

Steam will definitely find its way out, but I did find with mine (I am off-set about a foot and a half from center) that I will get drips off my cupola framing if the conditions are right. Of course those drips tend to hit my syrup pan.

[Birddog]

I didn't align my cupola with the evaporator and I get a lot of condensation where the steam his the roof. If I had it to do over I would align the two.


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[RC Maple]

I agree with wnybassman, the steam will get out. The less surface is has to come in contact with before that the better though. My pan isn't exactly under the center of the cupola and my "rain events" are few and minor.

[optionguru]

Thanks for the comments and experience. I think I'm going to make the cupola a little wider than normal but still centered, that way the pan is under it a little more but it doesn't throw off the "look".

[maple flats]

my cupola was centered under my 2x6, but now the 3x8 has the same size cupola and it favors the flue pan. My walls are also 10' high. I have steel roofing too. The first year on the 2x6 I had rain from the condensation. The next year I had made a hood and the rain stopped. Inside the hood, under the steam stacks I made a catch inverted funnel that drained to the hood gutter and out, it worked perfectly. Now on my 3x8 with factory hoods, they also came with inverted funnels to catch condensation running down the inside of the steam stacks. With this I even have the stack from the syrup pan hood, offset using 2 30 degree elbows before it goes up into the cupola. This works very well. If you want the cupola centered in the building and not over the epans you need a hood system. I made my own hoods on my 2x3, my 2x6 and my first 3x8. They all worked well. Then I was going to make my own hoods for the new 3x8 but when I went to pick up the evaporator pans from Thor Equipment, they had a demo hood marked less than half price because it had 2 small dents. I had a hard time finding the dents, so I bought that hood and now I still have a hard time finding the dents. The only way I can see them is with bright lights on the hood at an angle and I am looking at the opposite angle. The quote I had gotten to have a set of hoods made when I ordered the custom pans was $1975.00, The dents brought the price down to $800, and that included the 2 stacks each at 5" and one has a locking damper to hold position better for the flue pan hood. Later I did have to buy the 8" offset for the syrup stack, but even then they only hit me $150 and they even delivered it right to me. I have the offset so the stack vents into the cupola and I didn't need to cut ceiling joists and re-frame it.

[optionguru]

One more question, my shack is very close to a river and it gets a bit windy. The wind will hit the shack and cupola broadside, is there anything special I need to do because of this or will it just help the air flow through the cupola?

[wnybassman]

One more question, my shack is very close to a river and it gets a bit windy. The wind will hit the shack and cupola broadside, is there anything special I need to do because of this or will it just help the air flow through the cupola?

I would have the cupola doors work independently from one another so one can be wide open while the other is cracked to get a little cross breeze.

[PerryW]

One more question, my shack is very close to a river and it gets a bit windy. The wind will hit the shack and cupola broadside, is there anything special I need to do because of this or will it just help the air flow through the cupola?

I just open the downwind cupola door. of course, the upwind door has quite a few gaps in it so even when closed, it lets air in.

[PerryW]

Pete, looking at your plan, I would recommend centering the evaporator under the ridge so the stack goes straight through the peak. There's less problems with rain and snowmelt dripping through the stack opening. I would also recommend not installing ceiling joists directly over the pan to reduce the drips from condensation. The building will still be plenty strong enough.

[Mark-NH]

I have 10' walls with a centered cupola and offset evaporator. These are my personal observations and preferences:

I choose not to run any steam hood(s) on my 3x8 as I like the atmosphere and heat the steam produces. Without a steam hood you will definitely need some type of sheathing on the back side of your metal roofing or it will rain like the Amazon in there. I ran with just metal roofing over strapping for about 10 years and you almost needed foul weather gear to hang out. I since pulled up the metal roofing and decked with plywood and then reapplied the metal. Adding this layer made all the difference in condensation.

Because my evaporator is offset I also put a pine ceiling at the 10' level but left an opening over the evaporator. This helps to direct the steam straight up to the rafters and out the cupola.

Have fun

[optionguru]

Another thought, what do you all think about sprayfoam insulating the metal roof. We've done it other places on the property and it's worked well, I wonder if it would fix the condensation problem?

[maple flats]

Are you speaking of sprayed urethane insulation? If that's it, it will prevent the condensation BUT I'd wonder about the possibility of either a small piece of the foam falling into the syrup or since the surface when installed is so rough, it invites all sorts of bugs to make a home. Then they might contaminate the syrup. I guess either a hood mentioned earlier or a ceiling would address all those issues.