Density of blown-in insulation
I was in an attic with blown-in cellulose insulation that was installed in 1987. The insulation is generally uniform (though with some areas lower than others) and is installed at 12″ high, or about R-40 – not bad for 1987, but not to current standards in Northern Ontario. The installer’s form was available from back in 1987 showing a density of 2.35 lbs/ft3 – about 45% higher than the manufacturer’s website recommends. Will this negatively affect the actual R-value performance?
Also, it doesn’t look like proper air sealing was done at tops of walls, around lights, etc… It is a bit hard to justify ripping all this insulation out to do air sealing, but it also seems that adding an additional R-20 won’t help as much as it should w/o air sealing.
FInally, there is an old air exchanger in the attic that hasn’t been used for years. It has two large un-insulated ducts connected through the ceiling space. Seems to me this unit should be removed as it is likely decreasing the effective overall R-value in the attic quite significantly. Thoughts?
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