Sound-Conditioned Rooms

Dampening techniques depend on the use of dense construction materials and/or the designed placement of gaps and vibration cushioning between adjacent construction materials. Additionally, the further that sound conditioned spaces can be placed from noise sources, the better; however, there are obviously practical limits to the extent this can be achieved. A sound conditioned room project must address all room elements, including windows, utilities, walls, ceilings, and floors. Much like the flow of electricity, sound waves will seek (vibration) conductors, and any unbroken pathway can transmit noise and compromise sound reduction effectiveness.

Sound waves that survive dampening attempts can be further reduced by installing sound absorbing materials. The simplest of these include carpeted floors and acoustic ceiling tiles hung from a suspended ceiling. There are numerous and diverse sound absorbing material products available for walls, ceilings, doors, windows and floors. For example, mass-loaded vinyl (about 1 pound per square foot) is a common underlayment for carpets and can even be used between layers of drywall in wall systems. Door soundproofing usually involves the use of heavy materials, good gap seals and weather-stripping.

When installed in a wall, windows are typically the “weak link” that allows sound wave transmission. The most effective window soundproofing methods involve the installation of a second window system in each wall opening. This can be installed as a retrofit or specifically designed as a dual window project during new construction. Two separate windows and sills, with their panes placed at different angles and a void space between, provide the greatest noise reduction potential. Window sill construction and window frame mounting techniques that reduce sound wave propagation are important. One common framing technique is to construct non-contiguous framing, including split sills and headers. Using window plugs and covering window openings with layers of drywall are common, but less effective, retro-fit techniques.

Walls made of thick, dense materials offer the best soundproofing because they restrict sound wave propagation. However, this is often not a practical noise reduction solution for most buildings, considering space utilization and cost concerns. The soundproofing characteristics of traditional building materials can be enhanced by adding additional layers and reducing vibrations across wall elements. An example of this approach is the construction of a sheetrock (drywall) wall with multiple layers, where each layer is separated by blocks of  padding (neoprene, vinyl or other) or caulk. Additionally, the stud support edges can be fitted with a cushioning layer of caulk before the sheetrock is attached to the studs. The sheetrock can be connected to alternating studs on either side of the wall interior to further break the pathways for sound wave transmission.

Electrical services, plumbing, ventilation ducts, and anything else that will create a penetration through walls are another facet of soundproofing that must be considered. As with other room components (walls, windows, doors), the concepts of sound dampening and sound absorption apply to utility services. Vibration reducing mounts and sound insulating foam wraps for pipes and ducts are frequently used examples.