Insulation Considerations - Batts or Blown in??

Help Support House Repair Talk:

fastsvo

Active Member
Joined
Jun 6, 2018
Messages
25
Reaction score
1
I have a 1969 built home in Southern California that has existing blown in insulation (fiberglass?) from what seems like back when the home was built.

As you can see in the pictures, it's well below the joist levels and is dirty (will be vacuumed completely). I currently do not use it for storage because of it's semi low pitch (4.5ft standing height inside at the ridge).

So going forward, I am stuck deciding between R38 batts or blown in cellulose or maybe a combo of batts+cellulose blown over the top?? The plans is to air seal everything possible including where the roof meets the eaves (no soffits vents) which is really tight and difficult to reach. I have plently of canned lights (mix of old and new) everywhere and some are NON-IC rated, but I think with the LED conversions it's ok now to have the insulation contact these cans. Though, that one white can in the photo most likely will be replaced because its really leaky (I can see inside). Another option is to invest in those organic "hats" to cover all the cans.

The attic is well vented with fans. Another consideration, would be to add radiant barrier against the roof rafters. I have a couple of knee walls facing the exterior (with gable vents) - would adding batts here be a good idea?

One guy I spoke to wants to use unfaced batts, but for the small difference in cost, wouldn't it be better to have them faced? I think over the years it will look/stay cleaner, but I don't think the vapor barrier is needed in an attic like mine? He also mentioned that they can pull a sheet of clear plastic over the fiberglass to keep it cleaner in the attic. Won't that trap moisture?

Anyways, how would you do it?

Thanks!
 

Attachments

Snoonyb

Supporting Member
Supporting Member
Joined
Sep 30, 2006
Messages
4,446
Reaction score
944
Who ever did that, "just throw the romex where ever" needs to be shot. Attic wiring need to follow rules, in place, which prevent the possibility for damage.

Clear the Insul. from around the cans, because you don't know what lamps future occupants may install.

The vent 90, needs to terminate through the roof, in a roof jack.

I'd, and I've done this several times, lay R-13 unfaced in the joist bays to fill, then lay R-30, unfaced, on top, perpendicular to the joists.
 

fastsvo

Active Member
Joined
Jun 6, 2018
Messages
25
Reaction score
1
I'd, and I've done this several times, lay R-13 unfaced in the joist bays to fill, then lay R-30, unfaced, on top, perpendicular to the joists.
I am assuming this is to cover the top of the joists where insulation batts would normally miss it? (I see this as one advantage to spray cellulose).

The 90* vent is an old A/C vent that is no longer used (closed up with drywall from the inside) but it should be plugged at least.
 

Snoonyb

Supporting Member
Supporting Member
Joined
Sep 30, 2006
Messages
4,446
Reaction score
944
The R-13 is to fill the joist bay, and the perpendicular R-30 covers.
 

Latest posts

Top