Webinar Q&A

Acoustically enhanced gypsum board

Attendee questions

Acoustically Enhanced Gypsum Board Designed for High STC Wall Partitions webinar on November 12, 2020

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What is the difference between SoundBreak XP Wall® Board and SoundBreak XP Retrofit® Board?

SoundBreak XP Wall® Board consists of two layers of 5/16" high-density gypsum board bonded together with viscoelastic polymer between the layers and encased in heavy, abrasion and mold-, mildew, and moisture-resistant paper. SoundBreak XP Retrofit® Board is one layer of 5/16" high-density gypsum board with viscoelastic polymer on the back side covered by an additional layer of heavy mold-, mildew, and moisture-resistant paper. This provides the damped panel effect once applied over existing interior gypsum board walls where sound transmission has become a concern in a remodel application.

It was mentioned that less framing is better for achieving higher STC values. Is that also the case with staggered stud framing to further reduce sound transmission?

Staggered stud assembly STC values will not vary based on stud spacing. This is consistent between wood and steel staggered stud assemblies. There are examples of each in the SoundBook® 2.0..

What is your recommended method to attach wall cabinets to RC channels?

It is not recommended to attach wall cabinets to an acoustical wall that is constructed with RC channels because this installation will compromise the STC rating. And RC channels will not support wall cabinets. The sound of cabinet doors closing also introduces unwanted Impact Insulation Class (IIC) sound into the assembly.

Are all SoundBreak® XP® products fire rated?

Gold Bond® SoundBreak XP Wall® Board 5/8" is a Type X core product and Gold Bond® SoundBreak XP Ceiling® Board is a Type C (enhanced Type X) core product. Gold Bond® SoundBreak XP Wall® Board 1/2" is a not a Type X product but will provide enhanced sound protection in non-rated wall assemblies. Gold Bond® SoundBreak XP Retrofit® Board is a 5/16” thick board and it is not a Type X product. Products are not fire rated; assemblies can be tested for a fire rating. Refer to the Fire and Safety Information on our website for a more complete explanation of fire resistance ratings.

Where is the technical book of fire rated details for commercial construction located on your website?

The PURPLE Book® II is a resource for architects, contractors and inspectors for assembly details pertaining to Gold Bond® product applications in fire-rated construction. The book can be downloaded from the NGC Design & Resource Center.

Are comparable STC values available for wood framed partitions, most of which are load-bearing?

The SoundBook® 2.0 has many wood-framed partitions listed with STC values, including framing at 16” o.c. and 24” o.c. Sound tests are never tested under load.

Is 5/8” SoundBreak XP Wall® Board fire rated to achieve a 1 HR fire resistance rating?

An assembly is tested for fire rating - not a product. 5/8" SoundBreak XP Wall® Board is a Type X product and has been tested in multiple assemblies and can be used in many tested systems where 5/8” Type X are noted. SoundBreak XP Wall® Board is also abuse-resistant and is ideal for assemblies that require both sound and abuse-resistant attributes.

What is dimension between the two studs in the UL Design V488 with four layers of gypsum board?

The minimum dimension for this test is 1”. The minimum depth of UL Design V488 is 10 3/4”.

Which side is the sound transmission source?

Sound is measured as an assembly. The STC rating is the same regardless of which side of the partition the sound comes from.

Can the SoundBreak® XP® gypsum board be painted just like other gypsum board?

Yes, SoundBreak XP Wall® Board is a paper-faced gypsum board and can be finished and painted like other paper-faced gypsum board products.

Are wood studs typically better than metal studs for STC?

Light gauge steel studs (25-gauge metal) provides the best sound protection. Wood studs are more rigid and transfer sound more easily. Our SoundBook® 2.0 lists many examples of steel and wood partition assemblies with stud spacing at 24" o.c. and 16" o.c.

With staggered stud wall construction, separation of electrical boxes into different cavities is not feasible and putty wrap on the boxes becomes more important. Does the staggered wall configuration without putty on boxes still outperform single stud wall configuration?

Sound walls are tested without penetrations. The lab testing for a single wood stud wall 16" o.c. with 5/8" Type X on both sides is a 35 STC. A staggered stud assembly using the same materials achieves a 45 STC. Adding a layer of SoundBreak XP Wall® Board to one side of the staggered wall assembly tests to a 53 STC. Unless the staggered wall assembly had an unusual number of electrical boxes or other penetrations, it will outperform a single stud assembly using the same materials.

Does the SoundBook® 2.0 list assemblies with 16” o.c. framing?

The SoundBook® 2.0 sections are organized by 16" o.c. and 24" o.c. steel and wood, floor-ceiling assembles, chase walls, shaftwall partitions, area separation walls and roof-ceiling assemblies. Steel stud assemblies also list gauge of stud.

Are there designs with acoustical drywall on both sides of the partition?

Yes, there are tested assemblies using damped panels on both sides of the wall. Damped panel technology is very effective when used on one side of a wall assembly. Using it on both sides of an assembly is less effective at reducing sound transmission.

Please clarify the difference between "lab tested" STC and "field tested" STC.

The Sound Transmission Class (STC) is a single number rating of the effectiveness of a material or construction assembly to attenuate the transmission of airborne sound. The STC provides an indication of how loud transmitted sound is perceived to be by the listener. STC values are measurements that indicate a laboratory tested assembly. Field Sound Transmission Class (FSTC) references the same measurement of assemblies but they are tested on site in the installed location. The field-tested values are normally lower due to building movement and different installation methods.

Does it matter where SoundBreak® XP® is installed in a multiple layered gypsum board assembly?

An acoustically enhanced damped gypsum panel will provide the same sound protection regardless of where it is installed in the assembly. SoundBreak XP Wall® Board is encased in abuse-resistant paper and can be used on the outer layer of the assembly for abuse resistance.

What is the difference between acoustic sealant and regular sealant?

Acoustical sealant, or a non-hardening sealant, remains more flexible over time which is important to help reduce the vibration between spaces. Some sealants harden and could compromise the STC value by allowing for more sound vibration to transfer between spaces.

Can a damped gypsum panel be used on both sides of a partition to increase the STC rating? None of the presentation examples showed this.

Yes, but generally the benefit from installing the SoundBreak XP Wall® Board on both sides of the partition does not increase the STC value enough to warrant the additional cost. Our SoundBook®2.0 shows many designs to help guide your decision.

What is the difference between OITC and STC ratings?

Sound Transmission Class (STC) is the measure of sound that happens between interior spaces. Outdoor/Indoor Sound Transmission (OITC) is the measure of low and mid-frequency noises through exterior walls.