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Luke Kujacznski Posted: Feb 19, 2008 12:31 PM	Car Wash Mason, I have a client who is building a car wash. HE took the project over half way through. Here is what he has: The cieling will have Extratek(sp) panels on it fastened to OSB. We were supposed to spray 3 inches of closed cell foam on top of the OSB but the Extratek people are concerned with creating a moisture sandwich with the center being the OSB. So the were leaning twards using Tyvek between the Extratek panels and the OSB and then putting R-40 fiberglass in the attic. I need to know if I am asking for problems by sandwiching OSB between foam and a vapor proof panel and if I need to put plastic or tyvek on the underside of the the OSB or what? Any Thoughts Luke
mason Posted: Feb 19, 2008 02:23 PM	Sprayfoam would work tons better than the fiberglass in separating the outside temperature and environment from the inside temperature and environment. Which direction is the vapor drive? Normally it would be from the car wash to the ceiling, but when the car wash is not operating, outside air could go right through the fiberglass and condense on the OSB. If they are concerned about the panels leaking air (and moisture) to the OSB, they could spray the underside of the OSB with a vapor retarder coating such as asphalt mastic, polyurea, etc. Have them perform a moisture study on the proposed design, Get your supplier involved

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Comments

Luke Kujacznski

Posted: Feb 19, 2008 12:31 PM

Car Wash

Mason,

I have a client who is building a car wash. HE took the project over half way through. Here is what he has: The cieling will have Extratek(sp) panels on it fastened to OSB. We were supposed to spray 3 inches of closed cell foam on top of the OSB but the Extratek people are concerned with creating a moisture sandwich with the center being the OSB. So the were leaning twards using Tyvek between the Extratek panels and the OSB and then putting R-40 fiberglass in the attic. I need to know if I am asking for problems by sandwiching OSB between foam and a vapor proof panel and if I need to put plastic or tyvek on the underside of the the OSB or what?

Any Thoughts

Luke

mason

Posted: Feb 19, 2008 02:23 PM

Sprayfoam would work tons better than the fiberglass in separating the outside temperature and environment from the inside temperature and environment.

Which direction is the vapor drive? Normally it would be from the car wash to the ceiling, but when the car wash is not operating, outside air could go right through the fiberglass and condense on the OSB. If they are concerned about the panels leaking air (and moisture) to the OSB, they could spray the underside of the OSB with a vapor retarder coating such as asphalt mastic, polyurea, etc.

Have them perform a moisture study on the proposed design, Get your supplier involved

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