Insulation or air barrier missing?

[Matthew Barnicle]

Two story house with floor trusses and attached garage, room above garage.
A portion of the house is one story only. I am not sure if there should be blocking/air barrier and insulation in the area of the photo. The photo was taken from a scuttle opening in the single story portion of the home and the two story portion of the home is directly adjacent to that scuttle opening (the direction the photo was taken).
The garage ceiling is below the floor truss system, 2nd floor subfloor above.
The garage ceiling has insulation
There is no insulation/air barrier between the attic crawlspace the photo was taken from and the floor truss cavity.
My question is: Is there anything missing here? Should there be insulation and air barrier between the floor truss area and the attic space I was in?
Seems like the 2nd floor room above will be hot because of the hot attic air infiltrating the floor truss area.

[Jerry Peck]

My question is: Is there anything missing here? Should there be insulation and air barrier between the floor truss area and the attic space I was in?

First, a presumption: That the OSB wall shown for the second floor is insulated.

Now, what is missing is insulation extending from that second floor OSB wall down to the ceiling insulation in your photo.

I found that *all the time* and wrote it up *all the time*.

Just insulation installers *not thinking* ... wait ... no trade *thinks* anymore, do they? :(

The other way to have done it would have been to have installed the insulation on the garage ceiling at the floor of the second floor above ... but that takes "planning" and more "work".

[Matthew Barnicle]

Right, because otherwise there is hot air constantly infiltrating the space between floor and ceiling, right? Also, all insulation needs an air barrier, right? Otherwise it just becomes an air filter instead of insulation. So, the space would need blocking/plywood/drywall or some other material, correct?

In regards to the presumption that the OSB wall had insulation, its not visible, it would be behind the OSB, so I don't know.

What about the exterior walls within the truss space between floors. I am assuming that needs insulation also, correct?

[Jerry Peck]

Right, because otherwise there is hot air constantly infiltrating the space between floor and ceiling, right? Also, all insulation needs an air barrier, right?

Not an "air barrier", think of blown in (loose fill) insulation, it has no "air barrier", however, it should have a "vapor retarder" facing (the paper of foil on batts), otherwise, yes, the air will move through the insulation. Loose fill insulation is always placed "on" something, such as gypsum board, which serves as a vapor retarder itself, and certainly serves as a "air barrier" to some extent also, thus, gypsum board on the walls serves that same purpose. Not a "barrier", but a "retarder" in that is allows air and vapor to pass through it, albeit at a reduced rate.

So, yes, "something" (such as gypsum board) would need to be installed after the faced batt insulation was installed (not only to serve as a retarder, but to protect and cover the facing on the insulation, which is not allowed to be left exposed).


What about the exterior walls within the truss space between floors. I am assuming that needs insulation also, correct?

Correct. And, if not already insulated, that will be a job.

[brian schmitt]

matthew,
it is a requirement in our state that the insulation be installed with paper facing the floor sheeting and installed right up against the subfloor. you are losing heat from the conditioned space in that area between the insulation and the subfloor above. it may be different in your area?