Don't use anything that will create dust.....i.e., saw. That stuff is carcinogenic. Best insulation on the market, but cut it with a pocket knife or skill knife or butter knife if you can tolerate the tearing. By design, and few do, that insulation is supposed to be covered due to the carcinogenesis. (Offgassing chemicals) On exterior of hive fine, interior and you best put a layer of thin ply to provide a barrier to the bees.