here's my problem - circa 1900's house with single hung origional windows - in excellent shape. inside casing is wide painted pine (6"). if i remove it's gonna split so it not an option. i know there is a cavity around 4 sides of the window around 4" wide. anyone know what to do around insulating this - one idea was to drill holes in framing and blow the stuff in then plug it. is this the correct choice?
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