I want to insulate the interior walls of an unvented 3-foot high crawl space (with a cement floor) with R-19 insulation (NJ)--but I'm seeking advice on the type of insulation. What type is best? If I use batts, does it have to be faced or unfaced? Any fire code concerns? It doesn't matter what it looks like, asthetically speaking.

Also, I've seen that Owens and Johns Mansville sell a "basement blanket" type of insulation. It's nice b/c it comes in 4 or 6' widths for easier install. It's fully encapsulated, but not sure if it's overkill b/c it costs more than I wanted to spend--but it may save labor time/hassle.

Any advice welcome!