Is there more than one type of cavity wall insulation?
There are half a dozen options in insulation and they all have plus or minus depending on the particular job. The cheapest and easiest is plain old fiberglass batting, but it won’t seal cracks and holes very well. If you need an airtight seal you can get spray/squirt in foam but it’s expensive and does not handle fire very well plus it can make future repairs pretty aggravating. Then there’s foam board, dead air, radiation reflective, vacuum sealing, gas charging, and a handful of “space age” thingys I won’t even go into. But if you’re doing it yourself stick with the old standby fiberglass, at four “R’s” per inch it’s about as good as most applications will ever need.
