HushFrame Raft

HushFrame Basics

What is a HushFrame Raft?

The HushFrame Raft is a wood based decoupling device for ceilings, walls, and floors used to increase isolation of airborne and footfall noise transfer. Each Raft consists of 3 parts, the base (fastens to the framing), the silicone Vi-Bridge (connects the base to the block), and the block (furring fastens to the block).

What are the dimensions, weight, and quantity per package?

Each Raft is 4-7/8" long x 1-7/8" wide x 2-1/4" tall and weighs 4 ounces. The Rafts are packaged in bags with 225 Rafts per bag.

Is this product safe? Will the wood delaminate?

We hear this question for all of our clip products, but perhaps more often with the HushFrame Raft because of the unusual design. First, this product is fully tested for structural integrity and UL fire assembly. The structural integrity of the Raft and Raft assembly (Raft attached to wood furring or metal furring) is rated the same as any other traditional resilient clip system (generally metal clip with or without rubber and attached to metal furring). Second, the UL fire assembly ratings of the HushFrame Raft actually exceed performance of the other traditional resilient clip systems. The UL assemblies of traditional resilient clip systems are more complicated than implied and rarely installed per the actual UL assembly requirements. The UL assemblies for Rafts are quite simple and easy to achieve with standard installation.

Regarding delamination, the wood used in the Raft is not the standard plywood you will find at a local hardware store. It's imported wood that is several times stronger than standard plywood. In addition, a staple is driven through the top to add to the strength of the laminated pieces. If you find any delamination of Rafts, then please contact us so we can replace the Rafts before installation is complete.

Is this silicone that connects the base to the furring mount going to break?

Not under normal circumstances.

The silicone used will last well over 100 years without any change to the integrity of the silicone. The only consideration with this type of connection is that the furring mount should not rotate from the base. This is accomplished by following industry standard installation practices with the HushFrame Rafts installed on an even plane

If your joists or studs are significantly uneven and you simply follow the waviness of your framing with no consideration to the stress this puts on each Raft and the furring that attaches to the Rafts, then you will create rotational pressure on the Raft block which could lead to failure of the silicone connection.

 

Is the HushFrame Raft UL rated?

Yes, here are the current listings:

UL- M565 floor/ceiling with wood furring

UL- M548 floor/ceiling with metal hat channel

UL- U311 single wood-stud wall

UL- U340 staggered wood-stud bearing wall

UL- U344 single wood-stud shear wall

UL- W307 single-stud bearing exterior wall

UL- W473 metal-stud interior wall

Comparing to Other Decoupling Clips

Does the Raft perform as well as other decoupling clips?

In short, yes, and then some.

Not all clips perform the same and not all testing is equal. Generally manufacturers will test their own product as well as the products from their competitors. Advertised STC and IIC ratings from these tests only really hold true to that lab on that day within that year. Debates over which STC or IIC rating is better are had and customers are left not really sure what data can be replicated in their project and what data is simply marketing fluff.

To put it simply for the Raft, the STC and IIC performance of the HushFrame Rafts either meets or exceeds any testing available from any other resilient sound clip manufacturer when tested head to head in the same lab. HushFrame Rafts reached and usually far exceeded the industry standard of 50 STC and 50 IIC (STC - airborne, IIC - footfall) without any additional materials aiding the performance of the overall assembly.

This is especially rare in ceiling assemblies where solutions from competitors generally require lightweight gypsum concrete, some type of underlayment (rubber, foam, etc), specialty insulation, and/or multiple layers of sub-floor or drywall to add extra mass.

There is no rubber, how can these work?

Rubber used in clips, especially knock-offs that have become more commonplace lately, is most often not even a rubber that is ideal for vibration reduction. The Shore A durometer (rubber hardness) is an important measure of that rubber's ability to dampen vibrations.

A popular all rubber clip with metal ends requires a high Shore A durometer to maintain structure and to allow for consistent rubber extrusion. This higher Shore A requirement reduces performance signficantly, especially in the lower end where much of the footfall impact noise is experienced. Other clips have Shore A ratings in the 40's and 50's for similar reasons. Some red 'rubber' clips are more plastic based, which is very firm in comparison to low Shore A rubber. Performance achieved is still positive, but the softness of the rubber will ultimately limit performance. The harder the rubber, the worst the performance.

HushFrame Raft has a Shore A durometer of 25. This would not be possible within a typical resilient sound clip. This extra soft connection between the base and the block is what makes the HushFrame Raft achieve such impressive results. So ultimately, it's the lack of rubber that makes Rafts work as well as they do.

Would standard wood furring perform the same as the Raft?

Adding wood furring to existing framing before installing drywall does not improve isolation performance at all. Sound will transfer through the drywall, to the furring, and into the framing as if the furring was simply an extension of the framing.

Decoupling with the HushFrame Rafts is drastically different. The base of the Raft fastens directly to the framing, the furring fastens directly to the Raft block, and the drywall/wood panel fastens to the furring.

The only connection between the Raft base and the Raft block is the silicone bridge. It's the most decoupled connection of any clip solution that exists.

HushFrame Raft Installation

What kind of furring should I use with the HushFrame Raft?

You can use both wood and metal furring. Wood furring is recommended because it is easier to source and maintains a lower overall profile compared to metal.

Wood Furring: 1x2 or 1x3 wood furring strip. Readily available from any hardware store. Actual dimensions are generally 3/4" x 1-1/2" for 1x2 and 3/4" x 2-1/2" for 1x3.

Metal Furring: 25 gauge or 20 gauge furring hat channel, 7/8" tall. Splice channel by

What is the layout for installation? How many Rafts per square foot?

The standard layout for supporting 1 or 2 layers of drywall is 24" x 48". Meaning rows that are located on each end (for a wall, top of the wall and bottom of the wall) and a max of every 24" in between. Rafts within those rows on each end of the furring run and a max of every 48" in between.

This works out to about 1 Raft for every 4.5 square feet of surface space.

If you include mass loaded vinyl, Green Glue Compound, or any other material that will increase the overall weight of the assembly, then include this in your estimate. Increase the weight capacity of the Raft system by reducing the space between each Raft. Reduce the Raft spacing from a max of 48" to 32" and the spacing of each row from a max of 24" to 16", depending on the amount of weight supported.

If you are adding weight to the assembly in specific areas (TV mount, cabinet, projector, projection screen, acoustic products, etc), then increase the quantity of Rafts in and around those specific areas to avoid over loading the Raft system. Do not add up the overall weight of these items and then average out the overall weight of the entire assembly. The increased weight is specific to that location and the Raft spacing should be adjusted in those areas specifically.

Which screws are needed for installation?

Fasten the Raft to framing: Use 1-5/8" coarse-thread framing screws to attach the Raft base to the side of your joist or stud. Fasten one screw on each side of the Raft block, roughly centered.

Fasten Furring to the Raft: Use the same 1-5/8" coarse-thread framing screws to attach the furring to the Raft block.

Fasten Drywall/Plywood to the Furring: Use standard drywall screws to attach the drywall or plywood panels to the furring, generally around 1-1/4" for the first layer and longer screws for each subsequent layer.

How do I connect sections of furring?

If using wood furring, the simplest is to install the furring with pieces butting against each other. Before installation of drywall, add a roughly 6" piece of furring to the back of where these furring butt together and fasten through the furring into the backing piece. This will bind the furring pieces together and give the connection strength to support the drywall.

If using metal furring, you can use continuous runs of furring that are spliced together with a 6" overlap using a standard 1/2" steel stud screw to connect the two channels together.

 

Can I install the HushFrame Raft over existing drywall?

Technically yes, but not in good practice. Ideally, each isolation assembly would have one air gap between two leafs. Creating a second air gap over an existing rigid panel with any method (standard furring, resilient channel, resilient clips, HushFrame Rafts) will increase resonance issues in the structure and reduce performance significantly compared to a standard install.

If this is unavoidable in your project, then the Raft must install with the base fastened directly to the face of the framing (stud or joist) so the furring can attach to the top of the block instead of the standard attachment to the side of the block. This will increase the overall depth added to the assembly to around 3" for just the Raft and furring added to the Raft (assuming standard 1x furring).

The air space created between the existing surface and what will fasten to the Raft/furring should be insulated with a 2" to 3" insulation to help reduce resonance issues. There will still be resonance issues, so the best practice is still to install the Rafts directly to the framing.

Can I use the HushFrame Raft to level my ceiling or wall?

All Rafts must be installed in a flat plane. If your joists or studs are uneven, then this must be taken into consideration when placing the Rafts. Rafts can be very slightly recessed, if needed, and can extend up to 3/4" beyond the framing, if needed.

If your ceiling or wall is more than 3/4" out of plane, then you should consider leveling the framing using shims or by planing the joists/studs, as needed.

The furring attached to the Raft block should ultimately be level, or near level, to ensure a safe install.