Are there any major disadvantages to insulating interior walls including ceilings/floors of a split level ranch house witha walkout finished basement? My reasons for insulating would be for sound deadening purposes. I dont mean every wall in the house, but probably the downstairs den (walls and ceiling) and 2 bathrooms and possibly the master bedroom. I thought I remember reading somewhere that it is not a good idea for airflow or something but I cant remember exactly.
You shouldn't have/want airflow through a wall, under, or over it anywhere, any wall. Roxul works well and rigid, split polystyrene on the plumbing stack/vent/drains. I always insulate under the stairs as well.
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