[Greenbuilding] most permeable air barrier

[Ross Elliott]

You're absolutely right, John, there will be a great big open cupola on top, plus plenty of ventilation coming in the bottom through open doors, etc., I should have been more clear - the problem is the steel roof becomes a condensing surface, and rains down on the syrup and syrup makers, so I was thinking a permeable air barrier would let the water vapour through to the steel, but stop the drips on the return trip. Maybe I'm over-thinking this like a typical energy nerd, the old-timers just said to lay full wood sheathing on the roof deck (since some have learned from experience about putting the steel on strapping). 

Thanks,

Ross

From: "John Salmen" <terrain at shaw.ca>
To: "'Green Building'" <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] Most permeable air barrier
Message-ID: <02a901d0e418$3d0db180$b7291480$@ca>
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I would think the major design goal for a sugar shack would be ventilation ? and aren?t the evaporators hooded these days ? stainless steel vent hood kind of thing either mechanical or with a large chimney ? old ones I was in as a child had big open cupolas