Do I really need a cupola?

[heus]

I am boiling in one 12x16 room of a 2 story barn. Evaporator will be a 2x6 Phaneuf raised flue. There will be an approximate 2x8 hole cut into the ceiling.Above the room is an entire hay loft 36x24 with 4x5 doors on either end. There is no hay or anything else for that matter in the loft. If I opened one or both of the doors, would that be sufficient to let the steam escape? My gravity tank will be in the loft and I will pump sap into it from the gathering tank mounted on my tractor. I can pull right into the barn and pump into the top tank. If I don't have to build a cupola that would be great.

[BC Birch Tapper]

As the steam rises it needs somewhere to go. You may wish to consider a slightly wider hole unless you plan on funneling it somehow. Definately open up one or both doors to give the steam somewhere to go. Could even put a big fan up there to assist.
How is the roof of you barn constructed? Is there venting between the rafters? If so that would be best.
I would recommend building some sort of railing to avoid falling thru the hole at some later date. ouch!

Sounds like it may work.
good luck

[Jerome]

That would be an awful lot of moisture you would be putting into the old wood i would be worried about splitting and twisting in the timbers.

[maple sapper]

I dont have a sugar house myself. But, it would make sense to me if you had a coupula and opened the doors it would make like a chimney effect to get the steam out quicker rather than letting it build up and getting the entire underside of the building wet. especially on cold days.