Message Board Thread - "Cold air penetrating insulation"

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Cold air penetrating insulation JNTOOLS 3/9/2005
A large area designed for a built-in wall unit in my home, has a back wall that half of it is common with the out-side, the other half is common with the interior (please note that when I say half the wall, I do not mean front to back, I mean side to side) in other words the wall is 15 feet long and approximately 7 1/2 feet of it are common with the outside. The entire room is above a completely insulated garage. A few weeks ago when the temperatures outside were around 15° Fahrenheit, I noticed what appeared to be condensation on and around one of the power outlet cover plates, part of the surrounding sheetrock and along part of one corner strip. I used a Protometer moisture detector and it showed no moisture beneath the surface, so I assume it was condensation because it was just on the surface. After feeling the wall I discovered there must be a 40° Fahrenheit temperature difference between the half of the wall that is common with the interior and the other half that is common with the exterior.

It just so happens, that I was planning to take a course at ITC.

A few weeks later I had the local FLIR representative at my house demonstrating a E65, so I decided to have them take a look at the wall. This was just a quick demonstration, so there was not a lot of time or thought put into it and no emissivity changes were made to the camera. It seems that the camera was detecting some severely cold spots on that part of the wall. Temperature outside was approximately 35°F.

Using a small fiber scope I decided to look inside the wall where the camera showed a cold spot, entering the corner of one of the outlets to see if there was a lack of insulation. The finding was, that there was insulation inside the wall.

This brings me to my question (finally) is it possible that the 7 & 1/2 feet of the wall that is common with the outside was never wrapped with Tyvek and that strong cold wind is penetrating the brick outside and cooling down parts of the insulation, and if this is the case, does anyone know a way to detect if the Tyvek was ever installed in this area, without pulling off the brick facing?

Re:Cold air penetrating insulation IRJay 3/9/2005
My experience in the construction field and I a currently having a house built is that even when tyvek is installed it is almost always installed wrong. The taping and securing of the edges is mostly left undone and incomplete ... in that the stapling is the only attachment. It is supposed to be taped and sealed at the edges. In your case it appears that with no insulation in the walls or inadequate insulation these would not be greatly affected one way or the other with an improper tyvek job. You need to reinsulate the walls with material that is resistance to airflow such as expanding foam which can seal the wall effectively from air flow. I also recommend the new ceramic matrix reflective paint that will insulate and provide a reflective barrier on the wall. This prevents radiant heat transfer at the walls. Good luck.
Re:Cold air penetrating insulation JKEngineer 3/11/2005
If the problem is a cold wall that is causing condensation of room air moisture, then putting reflective or low e paint on it will make the situation worse. The room will be warmer and more energy efficient, but the wall will be colder with the low e paint. That will increase not decrease condensation on the wall.
Jack M. Kleinfeld, P.E.
Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

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Bronx, NY 10463

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