As a continuation of our Sound Control Roundtable feature, we asked a panel of manufacturers what installers and contractors should take into account before working with adhesive and underlayment sound control systems.

Panelists are Mike Micalizzi, Custom Building Products senior director, technical services; J. Alex Keene, Dependable division manager, floor preparation; David Jackson, DriTac field technical services manager; Arthur Mintie, Laticrete senior technical services director; Jeff Johnson, MAPEI business manager, floor covering installation systems; Beth Lee, Maxxon senior development and project manager; Deanna Summers, MP Global Products marketing coordinator; John Serraino, QEP vice president of product management; Sean Gerolimatos, Schluter Systems technical director; Blair Roberts, Schönox HPS North America marketing coordinator; Wayne Williams, Stauf director of training and technical/sales support; Mark Lamanno, Titebond/Franklin International technical market manager, flooring; and Brett Fleury, USG product marketing manager, tile and flooring solutions.

Fleury: Sound travels through an assembly like water. If there are any holes in the system, the sound will find them. This ‘short-circuiting’ of the sound attenuation system will effectively negate the performance of the entire assembly. In some cases, a short circuit of the system will reduce the STC and IIC ratings by up to 10 points.

This is when attention to detail is critical. Special efforts to prepare the system include filling holes and gaps with an acoustical sealant, installing a perimeter isolation strip, and taping all perimeters of the sound mat so self-leveling underlayment can’t leak under the mat are just a few of the special procedures required to ensure the sound system performs as designed.

Micalizzi: All sound membranes must be stored and installed in reasonable temperatures as they may not lay flat when frozen. They also require primers and mortars to cure or dry. Low temperatures can adversely affect these materials.

Substrates must be clean, dry and free of contaminants in order to bond and stay bonded. They must also be smooth to prevent voids under the membrane and tile assembly. Leveling or sloping should be done before placing the membrane. Limit final mortar thickness to 3/8” or less.

Some natural stone such as limestone and travertines, cement terrazzo and agglomerate tiles can have a tendency to warp due to the extended timeframe exposed to moisture in mortars between the membrane and underside. Permanent warpage can occur early or take around 20 days to become visible. Using excess mortar will increase this risk.

Lee: The primary considerations a flooring installer should verify prior to using a sound reduction mat or adhesive are performance and compatibility of the mat with the finished flooring. If the flooring installer recommends a specific sound reduction product, they are assuming the role of acoustical consultant for a project. If the mat fails to meet performance criteria, it is the installer that will be held accountable.

The same goes for compatibility. Not all adhesives or mats are compatible with all flooring materials. For example, the use of rubber sound control mats with LVT products may produce plasticizer migration, which can result in discoloration of the flooring or create an odor that is noticeable to occupants. If the flooring requires a glue-down installation, it is also important to confirm that the flooring manufacturer’s recommended adhesive is compatible with the sound mat.

Williams: First, care should be taken to ensure that there is a flat (3/16” in 10’) and stable substrate to install on. Second, ensure there is 100% coverage of adhesive to ensure no hollow spots are left to cause issues. Finally, confirm that the underlayment and adhesive are compatible. Some adhesives will not bond to certain types of underlayment.

Mintie: Before working with sound control products, installers should carefully consider the building code requirements for the project’s jurisdiction to ensure that the appropriate sound reduction performance properties are achieved. Installers should then examine the physical characteristics of the sound control product that is being considered for the application. Proper surface preparation and perimeter isolation joint treatments that ensure high-quality sound reduction are always a good idea.

Gerolimatos: To best answer this question, it is important for the installer to identify the floor assembly’s required performance. Whether it is exceeding code requirements for sound control or other functions such as waterproofing or load support, each underlayment offers its own contributions to an assembly and must be chosen accordingly.

It is also critical to check that a particular material will support the tile covering once the floor is opened to traffic. Review Robinson floor test results that most closely match your application to validate that a given product is suitable. If that information is not available in the product literature, contact the manufacturer to request it.

Lamanno: Considerations when using one of our three-in-one adhesives for sound reduction include: the flatness of substrate to allow the adhesive to form a continuous film, not letting the adhesive cure before you roll the adhesive to create the continuous film, ensuring you are using the correct trowel for a three-in-one application, and realizing that adhesive clean-up can be difficult.

Considerations when using an underlayment include: the flatness of the substrate, how the end-user will feel about a slight hollow sound, ensuring the flooring selected by the end user can be floated over an underlayment, the ability to double stick the underlayment, and taking into account other existing floorcovering that is problematic to remove.

Serraino: It’s important that installers always make sure they are using approved adhesives. They should always check with the underlay and flooring manufacturers to make sure the adhesives are compatible with their products and have been tested. Additionally, they should always follow the latest revision of the installation instructions or this could result in issues which will not be covered by warranty. 

Keene: Dependable recommends checking the tested systems prior to using any acoustical underlayment or adhesive. It is important to ensure the product’s tested systems match the system you plan to install it.  If they do not match, consult the product’s manufacturer for guidelines.

Johnson: In every situation installers need to take a moment to read the technical data sheet and installation bulletins for any product they install. This is important because the manufacturer of the sound control solution has done the hard work to determine and measure the sound reduction provided by the system. It is extremely important to install it per instructions to ensure the end user gets the sound control they purchased.

Jackson: One of the major keys to any successful flooring installation will always be proper subfloor preparation. As a general guideline, ensuring that the subfloor is clean, flat and dry is a critical element to achieving successful results, regardless of the preferred sound control method.

Roberts: Considerations include the building code, product specification, product coverage, amount of product required, prep and application time, and the manufacturer’s instructions for proper mixing and application.

Summers: Always read and follow the manufacturer’s installation instructions.