Although most homes have insulation in exterior walls, most probably do not have insulation in interior walls. Insulating interior walls is often viewed as an unnecessary expense. However, if you have a teenager who likes loud music, or a playroom where children squeal and shriek, you might find yourself wishing there was something to block the sound from passing so easily through the walls and ceilings. One way to decrease sound penetration of walls is to install another layer of drywall. A better alternative, especially when remodeling, is to simply install fiberglass insulation in the interior walls and in the ceiling of first-floor rooms. This is a relatively inexpensive solution that can be handled by the do-it-yourselfer.

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Add sound board on interior/bathroom walls