It's tough to give a good recommendation w/o seeing. If there is an enclosed cavity, blowing it full would be ok. Of course, if there is some insulation already there, it is more difficult to do a good job as the existing insulation interferes w/ the blowing. A basic truth is to maintain a continuous insulation envelope around the entire living space. If insulation is missing, replace it. If it's a space that's being used for storage, you may need to cover it so it doesn't get messed up (Perhaps w/ foam board). Also be sure all spaces outside the insulation envelope are ventilated.