If you don't want to loose ceiling height, you will need to remove the celing covering to gain access to the floor joist cavities.
A product we've had great sucess with is Roxul (http://www.roxul.com ... read more
Roof to wall intersections and pipe collars are probably the two most common locations. What is the height and pitch of the roof? I don't suggest hitting the roof with a bunch of water unless you kn ... read more