Considering replacing current blown cellulose with open-cell spray foam on attic floor. Is this crazy?
My wood frame and stucco home with cedar shingle roof is almost 100 years old. We live near Chicago (Zone 5). We have blown cellulose on the attic floor, ~r45. A furnace with duct work is in the attic (there was no other place to add a needed zoned furnace), in a small room with some rigid foam board. The duct work was sealed as carefully as possible and is covered in some cellulose.
About 5 years ago, there was too much moisture in the attic. After cleaning, we applied mildew resistant paint, and we added several vents with a fan on a timer and on a temperature switch. No issues since then.
Our house gets dusty (either that or my cleanliness standards are too high). I suspect some comes from the blown cellulose in the attic or the dense pack in the walls. Most probably comes from the outdoors.
I am considering having the r45 blown cellulose on the attic floor removed and replaced with r30 open cell spray foam (ocSF). Is this crazy? A recommended technician says that we will be better off with the foam due to its air sealing properties. Plus he can better insulate the ducts and small furnace room with the ocSF.
Would replacing the blown cellulose with ocSF reduce dust in the house?
Would it make moisture problems more or less likely in the future?
Would it reduce or increase our energy costs?
Are there other concerns I am not considering?
Thank you so much!
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