Attic insulation question

[gregs]

My house is a split level two story. The main single story part intersects the two story part a little below midway. The stairs are in the two story side with a flight up to the main level and another flight up to the second story. I was in the attic/crawl space of the single story side this weekend checking some things and worked my way over to the intersection point. I found an opening which is basically the ceiling of the upper stairs and it goes to the attic/crawl space of the two story side. I could carefully climb on the ceiling framing and go to the second story attic. It looks like they originally had the opening filled with a insulation batt stapled in place, but it fell down at some point. The wind out side was blowing and I could feel a good draft going up thru this area. I am wondering if this should be sealed and keep the two attics separated? They both have ventilated soffits and ridge vents in place. I am thinking if they need to be separated I could use a piece of rigid insulation to fit in the opening.

 

[Firebrick43]

It wouldn’t hurt to have a separation just for slowing a fire for improved egress times.

Could you place a osb door on hinges and latch to maintain access and glue some polyiso foam to the face of it?

 

[gregs]

Its tight on space up there. I would have to make it in a couple of smaller pieces to get it up there. I was thinking a rigid insulation "plug" would be sufficient. I thought about doing something like that because the scuttle hole in the second story is a pain to get to. This would be way easier access.

 

[Firebrick43]

The issue is many foams are not a good fire block. Polyiso is better than eps or xps in that department but not as good as osb or the even better x rated drywall.

 

[gregs]

Understood. I could do something with some OSB and make it removable. I dont think there is room to make it swing like a door.