Why Headers Appear Cool
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Why Headers Appear Cool
Tip written by: Infraspection Institute
In business, it is frequently said that cooler heads prevail. When performing infrared inspections of building interiors, window and door headers are often more prevalent.
Headers are a common construction detail found within building walls that utilize frame construction. Headers are horizontal framing members that are typically located at the top of window and/or door openings. In load bearing walls, headers are typically constructed of framing members that are stronger than vertical framing members.
When fabricating headers in wood frame construction, it is common to utilize framing members that are wider than vertical members. These are then often doubled in thickness and placed at the top of the window or door opening. Because headers are typically wider and/or double thickness, there is usually less cavity space for insulation to be installed wherever headers are present. In these circumstances, it is normal to see greater energy loss wherever headers are present when compared to a properly insulated wall cavity.
When performing an infrared inspection of framed walls from the interior of a building with cold outdoor temperatures, headers will typically appear cooler than insulated wall cavities. Observed thermal patterns will reverse should the same inspection scenario exist with warm outdoor temperatures.
For best results, a minimum inside/outside temperature differential of 10ºC is recommended when inspecting buildings with framed wall construction. Proper conduct of infrared inspections is addressed in the Standard for Infrared Inspection of Building Envelopes. Copies of the standard are available through the Infraspection Institute Online Store.
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