Apparatus for unrolling rolls of building insulation in vertical strips from the roof eave down, and adapted to be carried by an aerial work platform that in turn is carried by an elevator, has a pair of spars as well as an arbor and a tensioning control mechanism. The spars are spaced apart and are mounted to as well as project away from the aerial work platform. The arbor is carried between the spaced spars for inserting through the core of a role of insulation and allowing the insulation to be unrolled from the roll in the form of strips to be hung on the building. The tensioning control mechanism is provided for controlling the unrolling of the roll.