Insulation, Radiant and Vapor Barriers - Large metal "tabs" in openings cut in bi-level rim joist... insulate?

Doityourself.com community forum was created to provide answers to all questions related to home improvement and home repair. Doityourself community can help you find information about how-to topics on small fixes to large remodeling projects. With comprehensive how-to content and expertly moderated community forums DoItYourself.com makes it easy to tackle even the most complex home improvement projects.



PDA
nutlog
11-06-09, 01:31 AM
While replacing the drop ceiling in my bi-level, I noticed openings cut into the rim joist... I see rounded metal "tabs" sticking through, what appears to be the back of our aluminum siding, and can feel lots of cold air around them. Pictures below.

The rim joists currently have no insulation. And our basement gets damn cold in the winter; could these openings be the main culprit? Should I 1) insulate fully, using thick, rigid foam blocks around the whole basement ceiling? 2) Regardless of that, at least fill in these openings with spray foam?

Of note is that we do have a gas furnace, dryer, and water heater all downstairs (utility room is one room away from the family room where I see these rim joist openings)... I read that if we seal "too" well it could cause airflow/combustion issues. Any concern there?

I just don't know enough about construction to know exactly what these openings and metal tabs are for, and I'm sure one of you can look at the pics and know immediately what I'm talking about. :) Any advice would be much appreciated. Thanks!

http://www.nsmband.com/waz/stuff/RimJoist2.jpg

http://www.nsmband.com/waz/stuff/RimJoist3.jpg

http://www.nsmband.com/waz/stuff/RimJoist5.jpg

http://www.nsmband.com/waz/stuff/RimJoist6.jpg

http://www.nsmband.com/waz/stuff/RimJoist7.jpg