Should You Use HushFrame Rafts To Soundproof?
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A member of our soundproofing community recently asked me about a product called HushFrame Rafts. I had never heard of them before so I did some research. In this article I am going over the benefit of using HushFrame Rafts, the cost comparison to other similar products and what they are.
1) What Are HushFrame Rafts
I am usually very skeptical about soundproofing products. These Hushframe rafts are interesting though. They are a wood isolator used to decouple drywall from walls and ceilings using hat channels or wood channels.
One of the biggest benefits to Hushfram rafts is that you can use wood as a furring channel not just metal, and you can save some space when using the Hushframe Rafts.
According to their website, HushFrame rafts use Vi-Bridge Technology to reduce noise transfer through the clip into your drywall. Now that sounds like some fancy naming for a patented technology. That is okay as long as it works.
According to their website they can achieve 80% noise reduction, and an STC of 66. However, we don't know what 80% noise reduction really means, especially for bass frequencies and we don't know how the wall was built to achieve an STC of 66.
All this said, I would trust that these clips do in fact decouple drywall when installed correctly. So next let's look at another comparable product.
2) How Do HushFrame Rafts Compare To Other Iso-Clips
Now the biggest difference in HushFrame Clips versus the IB-1 Iso Clips I used in my studio are price and the total depth of the clip. First, let's take a look at price.
HushFrame Rafts are available at the ISOSTORE online for $4.95/clip.
The iso-clips I recommend I found for $1.79 at Buildcorpdirect.com.
The first important factor is to look at price. The A237 Resilimount Clip is $3.16 cheaper than the HushFrame Rafts. This could add up depending on how many clips you need. Most studios will need dozens of clips, so cost could be a factor.
Second we want to look at the amount of space each clip adds to the wall assembly. The Hushframe Raft as you can see below uses up to 1" of space if using 3/4" wood furring or 1 1/8" if using 7/8" furring channel.
Source Image: HushFrame Website
Now if you are using the IB-1 or A237 Clip (they are the same with different names) then you will have a 7/8" furring channel sitting in the clip with a few 16ths of an inch below the furring channel. I am not 100% certain on that exact height but it should be around 1" to maybe 1" 1/8". Either way, I believe the space saved using the HushFrame Raft is pretty minimal.
Below is a diagram of the A237 Clip:
Now let's look at a diagram from the Soundproofing Company Website that shows different STC ratings using the IB-1 iso clips and 7/8" furring channel.
You can see that if you use Green Glue between the layers and two layers of drywall with Green Glue on the backside you get an STC of 71. With one layer of drywall on one side and the hat channel system on the other side with Green Glue you get an STC of 67. If you use two layers of drywall without Green Glue you get an STC of 58. Those are all better than the HushFrame Rafts accept the STC of 58. However, remember we really don't know what wall system they were referring to. If you added another layer of drywall to the outside of the wall it would increase the STC regardless of your iso clip.
3) Conclusion
Would I use the HushFrame Rafts in a soundproof studio build? Probably not because I can get the same STC rating using a cheaper clip and the space saved is pretty negligible.
The only time I might recommend the use of Hushframe Rafts is to create a decoupled vent through your wall. I could see how using the rafts to build a custom ventilation system could be useful, but other than that I would stick with the cheaper clips and put your money on more drywall and Green Glue.