Basements, Attics and Crawl Spaces - rim joist insulation

I am removing ancient fiberglass insulation covering the rim joists. On top of the joist is John's Manville strongboard (like a fiberboard) and in front of that, closest to the inside, in some places, is some fiberboard. I plan to seal cracks, of which there are plenty,with Great Stuff and then put in unfaced fiberglass which I will cover with plywood scraps or sheetrock so the fiberglass is not exposed and shedding particles into the basement. There is a low budget available for this project. Are there any problems with this idea?

Hi Nora, your proposal sounds fine. Emphasis on air sealing as you stated. One of the issues you are addressing is air leaking out from the upper floors, it has to be replaced and results in air being drawn in on the lower floors.

Issues to be aware of are any moisture in the basement, leaks, dirt floors, or others. Once you seal up the fresh (cold) air source, you don't want mold to become an issue. The other is combustion air for your furnace/boiler. In some cases it is necessary to pipe in a supply of air for that system to burn. Lacking an adequate supply the system can draw CO back into the house from the chimney.

While you are in the basement with the great stuff, all electrical and plumbing penetrations can be sealed as well. Fire rated foam should be used when sealing wall access. Sheet metal or sheetrock works well for larger openings like around chimneys, bathtubs, or showers. You are preventing warm moist air from getting into your wall cavities and or ultimately into the attic.

stay warm
Bud

For some of us in this country, covering the rim joist conceals termite traffic, which is not a good thing. If you do block off those spaces, have an annual termite inspection, if you are in an area where they persist.

Only if affordable: http://www.rd.com/57548/article57548.html
Be safe, Gary