I am planning to add more insulation to my attic but I am not sure what type of insulation to use. There is about 5 inches of blown in insulation (no vapor barrier underneath) so I definitely need to add a lot more. I was thinking to add fiberglass blankets on top of the existing insulation but I am not sure if it is a good idea since the blown in insulation is not even everywhere. It ranges from 4-5 inches deep in some places and does not reach the top of joists, so there might be a small gap between the two if I decide to use blankets which would be installed on top of joists. Should I use blown in instead of blankets? Also, as I mentioned before there is no vapor barrier underneath the loose fill insulation. If I will add more of the loose insulation or will decide on blankets, is there going to be an issue with moisture and air penetrating the insulation and eventually getting through the ceiling?