Upper floor insulation

[Saintbacon]

Hi there.

I have a wooden 2nd floor above my steel garage that I'm planning to use for storage for now, but hopefully build the major components to one day support an occupant. I'm looking to insulate the walls. I'm in Rhode Island so I'm hoping to achieve an R value of around 20.

the 2nd floor is built as a loft. basically a platform built inside the garage but not particularly touching it. There's about a foot of space between the wood and the outside wall of the garage. I can see the ceiling of the garage around the edges of the 2nd floor.

The 2nd floor walls were built flat, so the larger side of the 2x4s are facing outward instead of towards the wall (See picture). (Note the R38 is for the ceiling)

My question is this:

Can I get an r21 insulation designed for a 2x6 wall and staple it onto my 2x4 flat studs? I'm guessing the issue is that the insulation will come apart and fall down to the first floor below.

Any thoughts around how I can modify the current situation to achieve this? I was thinking about using some strapping or wood lathe to hold it in place.

Thanks!

 

[billconner]

A real stumper. I know that fiberglass like you have much performs better when it's in a box - like studs, plates, sheathing, and wall board - with no surfaces exposed to wind washing.

If you didn't have the fiberglass, I strongly recommend rigid foam continuous on the back of the flat studs.

Sorry, no good ideas. I may come back if I think of something.

 

[Montauket]

You could fur out the the wall on the inside with another 2x on the flat and spray foam 3 inches for r21 . Air seal the window box and wrap it.

 

[thammel]

First, I don't think the fiberglass will fall after stapling. Not sure what your concern is except for the aforementioned wind washing. Since you have so much room, why not use R38 thicker stuff on the walls too? I believe this is 12" thick.

 

[billconner]

why not use R38 thicker stuff on the walls too? I believe this is 12" thick

A good idea but already bought other. Maybe could return. Still, where's it attached or fit? Maybe 8 or 12" batt's could be set horizontally behind flat studs. I did that between 2x4 walls - double framed on a 12" off wall - and worked great. No sag or mis-shaping at all. Almost like stacking blocks. Surprised me a little on just how "solid" it was.