Flanged windows that are integrated with continuous exterior insulation - rigid foam - typically get installed on a "bump out." In fact AAMA (American Architectural Manufacturer’s Association) and the WDMA (Window and Door Manufacturer’s Association ) say the "extension to the structural wall framing at the rough opening perimeter" is needed. It's easily flashed and the flashing membranes typically integrated with the "water control layer." This is all good. "Excellent, in fact," says Joe Lstiburek. "So what is my problem? It is just that the wood 'bump-out' is a thermal bridge."

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