Soundproofing wasn’t a typical concern when most older houses were built. The building codes were mainly concerned with the structural integrity of the house, not how quiet it was. Soundproofing is more of a design consideration in newer houses. Unfortunately, the quality of the construction and attention to detail are often more important than the soundproofing materials themselves.
It’s obviously easier to design a new house to be soundproof than it is to make an existing house quieter. Having said this, it’s still possible to make many soundproofing improvements to an existing house. Keep your goals reasonable by trying to create only a couple of quiet areas instead of doing the entire house.
In order to evaluate the proper soundproofing improvement options, it’s helpful to understand how sound transmission occurs in a house. Most of the noise, both indoor- and outdoor-generated, is transmitted through solid surfaces such as walls and floors. Noise can also travel by air leakage between areas. Third, loose vibrating materials both transmit and create noise.
When a noisy car drives past your house, it emits sound waves into the air outdoors. These sound waves hit the walls and windows, making them move. They, in turn, create the same sound waves inside your house, and you hear the noise. Some of the vibrating air also leaks indoors through doors, windows, and gaps without having to first make the wall or window vibrate. A loose window can also start to vibrate, significantly increasing the noise level.
You probably want to minimize the expense for your soundproofing improvements because you’re planning to move into your new house sometime soon. Installing new windows with argon or krypton gas in the gap between the panes will block much noise. Install these in your new house, but this is likely too expensive for an existing house. Instead, caulk any gaps and replace the weatherstripping to reduce the outdoor noise from air leakage.
To reduce indoor-generated noise, seal off interior doors with weatherstripping just like an entrance door. Installing heavy, solid wood interior doors can reduce sound transmission through the door material itself.
There often are hidden air passages between rooms in a house. Check where heating duct registers come into a room and the adjacent room. If you remove the register covers, you may see a gap straight through into the other room. Seal off those gaps. You may find the same situation with wall electrical outlets and switches.
For your new house, use double layers of drywall to block sound transmission. You may even stagger the studs inside the walls. Seal all the gaps between rooms, and run separate heating ducts to each room. Use high-mass floor underlayment for the second floor. Install the best windows and solid doors throughout.
