For high level soundproofing you need to employ some method of decoupling the framing from the drywall. This can be done by modifying the wall or ceiling framing, but decoupling is often accomplished through the use of furring channel with resilient sound clips.
Resilient isolation systems that utilize resilient clips require a quality Hat Channel to function. There are several manufacturers of these products and the specifications for them are defined by the Steel Stud Manufacturers Association http://www.ssma.com.
Technically, the Hat Channel is known as a 7/8” Drywall Furring Channel. For our purposes, we want:
- Gauge: 25 Gauge
- Height: 7/8”
- Acceptable width: 2 ½”, 2 9/16” and 2 5/8”
- Unacceptable width: 2 3/4” +
It is important to review how a resilient sound clip system operates. Because the clips are spaced 24” and 48” apart, there are far fewer contact points between the drywall and the steel or wood framing. This mechanical isolation helps to limit the direct conduction of vibration from the drywall to the studs.
The second important feature of the resilient clip and channel array is the introduction of resilience. Because the channel is attached every 48” by a resilient clip, the 48” span is allowed to flex slightly. This flex is very important to the systems overall performance.
This is why it is important to use a quality 25 gauge Furring Channel. 20 gauge material is commonly available, but is stiffer than we would prefer. 20 Gauge Furring Channel is not flexible enough.
Do not use Resilient Channel with Sound Isolation Clips
Resilient Channel, also known as RC-1
This is considered a “1 legged” material that is often used by itself to try and isolate sound. This is NOT a material specified by the SSMA and therefore there are dozens of questionable designs available in the marketplace. We discuss the serious limitations of Resilient Channel in another article, but for now, clearly this isn’t a product that can be used with Resilient Clips.
RC-2 Channel is also commonly referred to as resilient channel. Hat track, hat channel and furring channel are not appropriate names for this material.
This is a “2 legged” resilient channel that is also unspecified by the SSMA, and absolutely unsuitable for use with resilient sound clips.
History of Resilient Channel:
Resilient Channel was originally brought to the mass market decades ago by USG (United States Gypsum). The product was trademarked as RC-1, and tested extensively at Riverbank Acoustic Laboratories. Today many installers, architects and material retailers refer to any channel with one “leg” as RC-1. It’s important to note that USG hasn’t dealt with the original resilient channel design for years and years. Since then, many manufacturers have made a “resilient channel” and informally referred to previous USG test data for acoustic performance. This is entirely misleading and quite unfortunate. Resilient channel available today has many profiles, mil thicknesses and performance characteristics, so it really not possible to simply predict how any given piece of “resilient channel” will perform. Additionally any 1 or 2 legged resilient channel is not specified by the Steel Stud Manufacturers Association (SSMA). So there are no standards for its construction or use.
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