To remove, or not to remove (80 year old mineral wool)?
1940 farmhouse in Zone 3B with 2×4 ceiling joists in a vented attic. New metal roof going on soon is bringing the opportunity to upgrade the existing four inches of pre-war mineral wool insulation. This upgrade is all about keeping the house cool in extreme hot/dry summers which costs us far more than keeping it warm during short mild winters.
Is it worth removing the mineral wool “batts” in order to provide decent access to performing air sealing before blowing in loose fill? Admittedly the idea of also removing nearly a century of rodent droppings and a fair amount of cedar shingle shards is fairly attractive.
The only practical alternative seems to leave the mineral wool (which I don’t care for sending to a landfill) and just peel it back to perform air sealing less successfully.
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