Do I need to insulate a shared wall in the attic of my condo?
I’m in central Mississippi (Zone 3). I have an unconditioned attic.
I have finished air sealing my attic. I cleaned out the ridge/soffit vents then placed preformed channels so that the ventilation in my attic is appropriate. I have also repaired, sealed and insulated the HVAC ducts in my unconditioned attic (yes I know). I am getting prepared to bring the insulation up to its proper level with loose fill blown in. Currently I have 4 inches of rock wool (put in back in 1973).
THE ISSUE: I have shared walls in the attic on two sides. The material appears to be some sort of board material. It says “Georgia Pacific intermediate sheathing.” This is all I could make out. It looks like a solid black board. This is all that separates my attic from my neighbor’s attics. I have sealed around the edges of the board material, etc.
1. Will this dividing wall be enough to keep my neighbors’ hot attic air out of my attic?” If not, then what do you recommend I do? Insulate on my side of this board material? Something else?
2. I know I need a firewall. Could I do a firewall and cover my insulation concerns as well?
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