[Greenbuilding] most permeable air barrier

jfstraube at gmail.com jfstraube at gmail.com
Tue Sep 1 16:24:42 CDT 2015


I have seen what you describe work by accident in pig barns. Vapor moved up to metal roof, condensed and the drained down to exit long underside of steel and top of permeable membrane. 
A modest amount of air and vapor tight insulation ‎would help keep the interior surface above the dewpoint too....

Sent from my BlackBerry 10 smartphone on the Bell network.
  Original Message  
From: Ross Elliott
Sent: Tuesday, September 1, 2015 14:32
To: greenbuilding at lists.bioenergylists.org
Reply To: Green Building
Subject: Re: [Greenbuilding] most permeable air barrier

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>
Content-Type: text/plain; charset="utf-8"

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 



_______________________________________________
Greenbuilding mailing list
to Send a Message to the list, use the email address
Greenbuilding at bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org




More information about the Greenbuilding mailing list