We have a brick house built in 1914. There is no insulation in the attic. There is a floor in the attic but no ceiling. The attic is vented in the soffits and in the roof. There is an air conditioning unit in the attic with duct work going to the rooms on the top floor of the house. There is one dormer facing south. We do not want to blow in insulation under the floor but would not have a problem with laying insulation on top of the floor. What would be the best way to insulate this attic and with what type of product ?