Can’t find UNFACED insulation for attic in San Diego- Can I use faced insulation instead?
20 years ago, everyone in San Diego used Kraft faced fiberglass insulation, with paper side facing in. Now, science seems to say the paper facing isn’t really beneficial and was usually installed poorly anyways.
I’m replacing the insulation in a 1950s, very leaky home, in the attic. I will be using fiberglass rolls (please don’t suggest blow in or spray foam) on this project. Instead of waiting a month for unfaced rolls, is it really a big deal if I just use the faced rolls, with the paper face inwards towards the house?
This is a retro job so will be installing from attic. The flanges of the paper will not be sealed or stapled as plaster is already in place (ie: leaky leaky as far a “vapor barrier” goes.
Will it make much (any) difference if I just leave the paper on and stuff it in the ceiling joist cavities? I’d rather not peel it off as it makes a heck of a mess and is just more work, but certainly will if there is good reason to do so.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Paper face or not, you should at least try to seal up the bigger air leaks into the attic. Especially now that you have some access. I'd wager that those leaks are going to make a bigger difference in comfort and energy bills than whether you have paper facing or not.
You want the ceiling to be an as close to perfect air barrier and vapor barrier as you can get it. Having paper facing pointed toward the living area will help but may not be enough. The biggest thing is to remorselessly seal every penetration in the drywall while you have the insulation out.
DC,
" remorselessly seal "
I'm stealing that description.
This.
Just do this.
Thanks for the reply!
1. All penetrations are sealed already. Is there any benefit to spray foaming where ceiling plaster and wall plaster meet (IE: top of top plate from attic side)?
2. So the paper face won't do any harm in this situation, right?
Paper face does no harm and may be beneficial.
Without looking at the house I can't tell how well sealed it is. I'll just say there's sealing and then there's sealing.