I would ask if the construction in and around this window has been analyzed carefully in relation to the local climate and sun angles before proposing a barrier between the conditioned interior and the window. As with mass walls that are modified with added interior thermal barriers, the existing construction will lose much of the benefit of the high heat transfer and vapor diffusion rates that may have allowed the construction to last so long.
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Drake A. Wauters, AIA
TDBP Advisory Group
Architectural Technical Director
Arlington, Virginia
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