What Can You Put on Existing Walls to Block Noise?

Soundproofing Methods

• Add an extra layer of drywall to walls to increase mass and padding against loud noise. Hang heavy tapestries and other thick wall fabrics for not only decoration, but also for sound absorption. For hallways and nearby rooms, put down carpeting on hardwood or laminate floors to reduce the amount of sound traveling from one room to another. In commercial settings, concrete slabs, solid masonry and custom-made steel are often used in soundproofing applications.

STC Ratings

• Research STC ratings and their relation to sound transmission levels to distinguish between insulation materials and to ensure you get the results you want. For example, the Minnesota Sustainable Housing Initiative at the University of Minnesota states that wall assemblies with STC ratings between 25 and 35 fail at blocking normal to loud levels of speech. Walls with an STC rating between 40 and 42 provide some noise blocking capabilities, but loud voices in nearby rooms may still be audible at a low murmur. Sound insulation products with STC ratings from 45 to 60 significantly reduce sound from loud conversations, stereos and musical instruments. At an STC rating of 50, noise can only be faintly heard through the walls. Wall insulation rated 60 and above produces superior soundproofing and blocks virtually all sound from entering the room.

Expert Insight

• Soundproofing materials are most effective when they are installed in walls during construction. However, isolating the source of weak links in existing structures can help you improve sound control if your existing walls contain poor insulation. These weak links or flanking paths -- areas where air gaps are present -- exist primarily around windows and doors. Nationally syndicated news columnist and Ask the Builder writer Tim Carpenter suggests installing a solid wood or solid core door in rooms with problematic flanking. Using high-performing weatherstripping around interior doors also prevents air penetration and leakage.

Considerations

• Determine where the noise is coming from before you devise an installation plan for soundproofing your walls. If you are starting from scratch or remodeling an existing room, hire an acoustical engineer who can help you choose wiring, piping, heaters and air conditioners that will produce minimal noise. You can also conduct a sound study before moving into an existing residence. Listen for loud noises in nearby apartments or on the street during different times of the day. Flagging sound insulation issues before signing a rental contract or purchasing agreement will avoid frustration and additional building costs in the long run.