Depending on where you’re building, you might actually be better off without insulation. Tropical and sub-tropical climates where it doesn’t get very cold in the winter are good candidates so long as you’re using reflective roofing to deflect the sun’s heat. What’s wrong with insulation? In a moist environment such as a coastal location, several types of insulation can hold moisture and possibly harbor mold and mildew. And looking at the roof structure like in this unit can be much more interesting than looking at a drywall ceiling, don’t you think?