Insulating rim joist- old construction

[jbos333]

Hi all

I'm sure this has been covered somewhere on here before, but I couldn't find it....

My existing house has no insulation on the rim joist in the basement. I was hoping to insulate it with fiberglass insulation I already have- R-19 Kraft faced rolls.

Is it worth the effort? I've looked on some related websites, some say foam is the way to go, but I'd like to make use of what I've got already. If I do this, which way would the kraft paper face? The basement is semi-heated with either woodburner or hot air furnace, but not "living" space.

[glenn kangiser]

The vapor barrier goes toward the heated space (inside).   If it's what you have, use it.  Insulation is insulation if it is usable in your situation.  Seal any air movement cracks first could also help.  Where are you located?  You can edit your signature in your profile to show your location and it will help others to provide pertinent suggestions.

[jbos333]

Thanks for the reply, Glenn

I have updated my profile to show I am in Western NY so it gets kinda cold and snowy around this time of year, although it was near 70 deg. yesterday its in the 40's today.

[glenn kangiser]

If you also add it to the line in your profile information that says "Personal Text".  It will appear under your name on each post.  A bit confusing but that's the way the software is.

I have a few relatives in NY, but it is way too cold for me.  I can see why you would consider adding insulation to the exposed foundation areas.

[MountainDon]

Back when we lived in Western Canada we faced the same problem. In really cold weather (-30 or so) the rim joist in the basement would actually frost up. I insulated it with sheet foam cut to fit and then sealed the edges where foam butted against wood.

Fiberglass will work; just not the same R per inch. As Glenn mentioned sealing the warm side of the insulation is important. You want to keep the warm air from being able to infiltrate and contact the cold. That could lead to condensation behind the insulation. Also go around the rim and seal any point where cold air from the outside might enter.

Do you have enough fiberglass on hand to do the whole job? If not you might consider a first layer of foam sealed to the cold rim with fiberglass added.