I'm wanting to add insulation to the exterior walls of my house, one company told me that blown insulation told me that they couldn't blow in any insulation unless I took off all my drywall, because the new insulation wouldn't go around the oldAnother company told me that they could do this without taking down the wallsMy question is who's right, if I hire somebody to do this I want to make sure that my new insulation is installed wellThanks in advance.
