I am in the process of installing R25 Johns Manville Comfort Therm fiberglass batts in the joists above my basement. I won't be able to finish the ceiling for a couple of years, but how can I keep the batts in place? They seem to stay in place by friction, but are there straps (etc) to keep them from falling out of the joist space?
You can buy stiff wires made for that purpose. They come in different lengths for different spacing of joists. A box of 100 is very inexpensive - I don't remember for sure, but it seems like around 3 dollars. They are a little longer than the space between the joists, and just stay in by spring tension.