Insulating a Metal Building with High Humidity
Im needing to insulate/seal a Steel I-beam Building that will be used for Poultry Processing. Location is in Zone 2 (southern Florida) There is a lot of inside moisture/humidity caused by the meat processing. The interior will be air Conditioned. The current (empty) wall & Ceiling envelope is corrugated metal siding on the exterior and a Metal Liner Panel on the interior, both attached to metal purlins & guilts that are 8.25” My concern is moisture caused by humidity or condensation forming inside the double sided metal wall&ceiling envelope. With the possibility of moisture entering from both sides I’m not sure where my vapor barrier should go. Under the siding, over the liner panels or somewhere in the middle? Although I know it’s a good choice I’d like to stay away from closed cel spray foam sprayed directly to the metal siding, iv been in some barns that make noise all day long from the metal expanding and contracting. Does anyone have experience with a similar build in a similar location? & or What are your thoughts?
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You want the vapor barrier to the outside, vapor open to the inside so it dries to the interior and the air conditioning removes the moisture.
What's going to be tough is that I imagine for sanitary reasons you're going to want walls and ceilings that can be washed. It's tricky to make them vapor open. On the BuildingScience.com website Joe Lstiburek has pictures of what happens when you have a vapor barrier on the interior in a hot humid climate, it's not pretty.
https://buildingscience.com/documents/insights/bsi-055-in-the-deep-end This might be a good read
Good stuff. Thank you.
These are always done with metal insulated panels (rigid insulation between two metal skins), these work in any climate and have no issues with indoor or outdoor humidity and can also be pressure washed. Not sure you want to use anything else. The cavity space in the rest of the structure can be left empty.
Depending on how cold the inside is and what the panel R value is, you can blow some loose fill over it in the roof area. You have to watch that the surface temperature of the panel's outside skin doesn't drop bellow outside air dewpoint in the summer.
I don’t believe something like that is within my budget. That would solve all my issues though.
Add this to your reading list: Insulating a Metal Building by Martin Holladay.