General Questions

What is HushFrame?

A brand of sound isolating Raft connectors for noise reduction. The term "HushFrame" is a proprietary trademark.

What is a Raft Connector?

Simple wood and silicone soundproofing decoupling devices that are installed inside walls & floor/ceiling assemblies of buildings to attenuate the noise that can pass through the assemblies.

Why are they called "Raft" connectors?

They're called Raft connectors because just like a wooden raft floats on water, these Raft connectors float the wall, ceiling, or floor finish on the assembly superstructure. The term "Raft" is a proprietary trademark.

What does "Vi-Bridge" sound control technology mean?

The term "Vi-Bridge" is a proprietary trademark and it represents the patented design, configuration, and performance of the silicone core of the Raft connectors.

How do you define noise?

We define noise as any unwanted sound.

How do Raft Connectors attenuate sound?

Our Raft Connectors route the structure-borne sound vibration through the Raft connectors, where the sound waves travel into the silicone core, get bogged down, and their energy dissipates as a small measure of heat.

Why have Raft connectors been developed?

To fill the need for an inexpensive and simple sound absorbing solution for builders to obtain code mandated STC and IIC ratings for lightly framed building assemblies in multi-unit construction.

What are Raft Connector products made from?

Two plywood components, a structure mount and a finish mount, separated and securely held by a core of silicone rubber.

Why are HushFrame Raft connectors made of wood when I see many types of sound clips made of metal available on the market?

In response to industry demands for a noise control solution that is wood-system friendly ... and HushFrame Raft connectors are exactly that. They can be installed with nails, screws or adhesives, they can be cut, trimmed or modified, and most importantly, they don't require the use of metal hat channel.

How effective are HushFrame Raft connectors as a sound absorbing product?

In a word, very. A typical installation will result in a 50% to 80% reduction of noise moving through a given assembly. To see a video of how Raft Connectors were tested to secure this claim click here.

Are HushFrame Raft connectors expensive? How do they compare with metal clips?

HushFrame Raft connectors are less expensive than metal clips and when you factor in the simplicity of installation, there's significant labor savings as well. Arguably the lowest cost noise isolation technology per installed decibel of reduction.

Application Questions

Where can I see full installation instructions for soundproofing?

Check out HushFrame’s full Use and Instruction Guide for Raft Connectors.

How are Raft connectors used?

Raft connectors can be installed on the face of studs, rafters and joists or they can be installed inside the stud or joist bay. They are also mounted on concrete walls and slabs, on top of wood sheathed floor decks, as well as utilized in the vibration isolation of pipes and mechanical equipment.

How are Raft connectors attached?

Typically, they are installed utilizing screws, but nails and a limited number of adhesives are also possible. Check out the installation guide for ease of soundproofing guidance.

Can I use metal hat channels with Raft connectors?

Yes, while raft connectors were specifically developed for the wood-based stud-frame industry, nothing precludes attaching metal hat channel to the Raft connectors in place of wood furring, and the Raft connectors perform just as well when they are attached to metal studs and joists.

Can HushFrame Raft connectors be modified?

Yes, to a degree, trimming the structure mounts to fit tight spaces for example, but care must be taken to avoid 'short circuiting' as is outlined in the Installation Guide.

How much living space is lost when I install Raft connectors?

Very little. Depending on the soundproofing decoupling device and application chosen, you can effectively eliminate your noise problem with as small an increase in assembly depth as 1/4" but 1" would be typical.

How long will HushFrame Raft connectors last?

They should last the life of the building. HushFrame Raft connectors utilize pure silicone rubber for the core which is unaffected by chemical or atmospheric assault. The silicone manufacturer offers 50 years as a minimum.

Can I install with wood, metal or concrete assemblies?

HushFrame Raft connectors are compatible with wood, metal, and concrete assemblies, with unrestricted finish on top of subfloor sheathing, and minimal incremental square footage cost of construction.

Testing Data

What are UL, STC and IIC? What is required?

Building components, i.e. walls and floor/ceiling assemblies, that separate dwelling units from each other and from common and service areas of buildings are required to meet minimum standards of fire resistance and control of noise transmission. UL LLC, formerly Underwriters Laboratories, performs fire chamber testing and certifies assembly designs and products that achieve the required fire resistance. STC and IIC values relate directly and inversely to decibel levels of sound. Therefore, the higher the STC or IIC rating of a particular wall or floor/ ceiling assembly, the lower the decibel level of sound that will be heard emanating from it. Current building codes mandate a one-hour fire rating for both these assemblies and also man- date a minimum STC 50 for the walls and an STC 50 and IIC 50 for the floor/ceiling assemblies. HushFrame Raft connectors are patented, acoustic lab tested, certified to provide superior STC/IIC ratings, and have passed UL floor/ceiling fire testing.

Are HushFrame Raft connectors fire rated?

Yes, our high-quality raft connectors have a Class 'B' fire rating, the same rating as the framing lumber they attach to. They offer a layer of security in that the temperatures where wood framed assemblies combust are normal operating temperatures for the silicone core, meaning the HushFrame Raft connectors will be that last component to fail.

Have HushFrame Raft connectors been acoustically tested?

Yes, by Riverbank Acoustical Laboratories. Extensive certified acoustical laboratory testing shows that HushFrame Raft connector sound attenuation performance matches or exceeds that of the most effective alternative technologies currently available.

How strong are they? Have HushFrame Raft connectors undergone structural testing?

Surprisingly strong, the raft connectors can actually withstand a multiple of the rated loading. While the silicone core is flexible, it is also very strong and tenacious. Production of HushFrame Raft connectors are tested routinely for tension, shear, and compression loading utilizing a Test Resources 140Q dual column test system.


What does 'STC' stand for?

It stands for Sound Transmission Class and it is an integer rating of how well a building partition attenuates airborne sound. In the USA, it is widely used to rate walls, floor/ceiling assemblies, doors, windows, and exterior wall configurations (see ASTM International Classification E413 and E90).

What does 'IIC' stand for?

It stands for Impact Insulation Class and it is an integer-number rating of how well a building floor assembly attenuates impact sounds, such as footsteps. A larger number means more attenuation. The scale, like the decibel scale for sound, is logarithmic. The IIC is derived from ASTM method E989, which in turn uses a tapping machine specified in ASTM method E492.

What does the building code require?

The IBC and State codes require a minimum STC and IIC rating of 50 for wall, and floor/ceiling assemblies separating dwelling units and between the units and the common, and service areas of buildings.

What does 'short circuiting' mean?

An example of short circuiting is when the fasteners securing the furring to the finish mount of the connector, are too long or over-driven so the fastener traverses the silicone core and makes contact with the structure mount. This allows the sound vibrations to travel directly across the fastener to the opposite mount unimpeded, bypassing the sound attenuating effects of the silicone core.

What does 'flanking' mean?

Flanking occurs when sound vibration finds an unprotected path around the sound attenuating assembly construction, either around the perimeter or through improperly protected penetrations such as light fixtures, switch boxes, ducts, or pipes.

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