Some but not a lot of basement ceiling insulation

[shetc]

Hi All - I decided to upgrade the insulation on my basement's rim joist by replacing old fiberglass batts with solid foam board. For some reason, there is a small section of the ceiling that also has fiberglass batts, but not the whole ceiling. It's sorta located below where the kitchen dining area is. Any idea why the previous owner would have done that? Cold feet while eating dinner?

 

[Bobby_M]

I can't imagine a purpose unless the basement is particularly cold.

 

[Deadalus]

If the basement is unheated space you would insulate the floor above. The vapor barrier would be against the kitchen floor. The owner maybe had a roll left from another project, I think there are 5 batts to a package So maybe started to work on the basement but didn't finish it. Or somebody else had an extra package and gave it to the owner.

 

[day_trippr]

Is there some noisy laundry equipment below the insulated area?

 

[shetc]

I can't imagine a purpose unless the basement is particularly cold.

It averages around 55 to 65 F through the year. Lagers in the winter

 

[shetc]

Is there some noisy laundry equipment below the insulated area?

No. That's the strange thing - it is placed near where our kitchen table sits, which is next to a kitchen counter.

 

[shetc]

If the basement is unheated space you would insulate the floor above. The vapor barrier would be against the kitchen floor. The owner maybe had a roll left from another project, I think there are 5 batts to a package So maybe started to work on the basement but didn't finish it. Or somebody else had an extra package and gave it to the owner.

From my Interwebz research, it seems that getting the rim joist insulated properly is the main concern for a basement. There does seem to be some disagreement about insulating the ceiling. But perhaps I misunderstood.

 

[FloppyKnockers]

+1 on unfinished task.

 

[Deadalus]

From my Interwebz research, it seems that getting the rim joist insulated properly is the main concern for a basement. There does seem to be some disagreement about insulating the ceiling. But perhaps I misunderstood.

Rim joist is good to insulate, it made a world of difference in my garage. If the basement space is unconditioned and little used/unfinished you would want to keep the heat in the living space above it. Or you could do the basement walls if it is heated. Or if unheated you could do the parts of the block wall that are above ground. Cinder blocks have very low R-value 1.9-2.5 which if they are above ground makes them another place for heat to get out.
https://www.energy.gov/energysaver/where-insulate-home
Been about a decade since I had to buy insulation but it looks like a common number of batts is 8 or 11. I kind of remembered it wasn't a lot as the batts are only 48", so 4-5 wall bays. Anyway, the owner likely had extra and had a place to put it. You might find the same R-value and brand in the attic perhaps. Or a buddy gave it to them, it's a pain to store once you cut the package open. I had a few extra batts bagged up without a good place to really keep them for a while.

What I am wondering is why the previous owner skipped that bay. Is it not 16" on center?

 

[shetc]

Rim joist is good to insulate, it made a world of difference in my garage. If the basement space is unconditioned and little used/unfinished you would want to keep the heat in the living space above it. Or you could do the basement walls if it is heated. Or if unheated you could do the parts of the block wall that are above ground. Cinder blocks have very low R-value 1.9-2.5 which if they are above ground makes them another place for heat to get out.
https://www.energy.gov/energysaver/where-insulate-home
Been about a decade since I had to buy insulation but it looks like a common number of batts is 8 or 11. I kind of remembered it wasn't a lot as the batts are only 48", so 4-5 wall bays. Anyway, the owner likely had extra and had a place to put it. You might find the same R-value and brand in the attic perhaps. Or a buddy gave it to them, it's a pain to store once you cut the package open. I had a few extra batts bagged up without a good place to really keep them for a while.

What I am wondering is why the previous owner skipped that bay. Is it not 16" on center?

It's all 16", and yeah, it's odd

 

[SanPancho]

that

Hi All - I decided to upgrade the insulation on my basement's rim joist by replacing old fiberglass batts with solid foam board. For some reason, there is a small section of the ceiling that also has fiberglass batts, but not the whole ceiling. It's sorta located below where the kitchen dining area is. Any idea why the previous owner would have done that? Cold feet while eating dinner?

look at the R of the batts, see if it matches the joist depth. cant see from the photo. if its 13/15 then its left over from insulating walls somewhere. if it matches your attic insulation then that's obviously where it came from as leftovers.

unless you've got something specific there to insulate like plumbing lines/ fresh air duct/heat ducts, etc there's no reason for it. they just must have figured why not?

as for your area at the end of joist bays, you can put foam next to rim joist, but honestly you could just slice up the batts and stuff them over against the rim joist. cut them to length ( the joist depth) and stuff it sideways. since they're not really doing anything under the kitchen you might as well get some use out of them.

if you've got the time, it couldnt hurt to put vapor barrier on those joists, especially if there's poor ventilation and you're brewing down there. the barrier is cheap, so are the staples.