FAQs

Lay out the cement board to span seams and run perpendicular to the long dB4 Max or dB 3 seams. Fastening along the cement board perimeter are recommended the secure the movement of the cement board. Screws provide permanent securement. The dB4 Max should be placed with the barrier side up against the cement board. Remember the more screws used more sound is transmitted.

Carpets installed using pressure sensitive or viscoelastic adhesives can usually be removed without damaging the dB underlayment. Adhesives that dry rock hard such as premium vinyl floor adhesives create a permanent bond with the dB material preventing the carpet from being removed.

For concrete floor installations dB4 Max is to be installed with the fiber side down against the concrete. A visco elastic adhesive is to be used to secure the dB4 Max to the concrete. dB3 is installed with either side down using the same adhesive as used with the dB4 Max. See technical data for adhesive recommendations.

Carpet or tiles with peal and stick adhesive may be attached to either product. Clean the dB material surface with spray cleaner an let it dry before installing the tiles or carpet. The dB material may scuff during transit exposing calcium particles. Cleaning will remove any dust.

For Radiant floor heat installation, we recommend they use dB3-1lb material with electric radiant heat. The design temperature of the heat strips should not be greater than 120 degrees F. We do not recommend using dB materials with hot water radiant systems as water temperatures can reach 180 degrees. dB materials begin to soften at temperatures above 150 degrees. The radiant heat strip material should be installed over 1/4 ” Hardie or similar cement backer board. The in-floor heating can then be placed on the backer board. The backerboard can be adhered to the dB3 material with 3M High Strength 90 spray adhesive. The same adhesive can be used to secure the dB3 to the subfloor on top of the dB3.

dB3 is mostly limestone and is rated as a Class C Flame Spread.

dB4 Max is not recommended under gypcrete or thin layer concrete. The dB4 flexes which can contribute to concrete cracking.

Sound damped drywall (QuietRock, Sound Break) performance will vary slightly depending on the manufacturer and the specific product.  For a general rule of thumb damped drywall STC test information indicates that it will perform about 1-2 STC better than MLV in typical wall assemblies for both wood and metal framing. Keep in mind that 1-2 STC difference cannot be discerned by human hearing, it has to be measured electronically.

Examples: 

• 2×4 wall at 16″ oc with insulation and 5/8″ gypsum has a STC of 32-34
• 2×4 wall at 16″ oc with insulation 1lb MLV on one side and 5/8″ gypsum on both sides has a STC of 38-40
• 2×4 wall at 16″ oc with insulation damped drywall on one side and 5/8″ gypsum on the other has a STC of 40-42

The performance depends on the framing spacing, the framing material, and construction quality. Light gauge metal framing will be approximately 8-10 points greater in performance for both damped drywall and MLV.

Damped drywall must be installed carefully as making repairs to holes or broken corners will reduce its performance.

Damped drywall is square edged and not tapered to receive joint compound

Damped drywall should be cut with a saw it is not designed to be snapped. QuietRock makes an easy snap product, but I do not know how well it works.

 If the design uses several sound control materials on the same wall assembly, the STC improvements when adding additional acoustic materials decrease for each additional material as materials are added.

I suggest if you want to use all of the materials in combination do it with one room only. 

I am not aware of testing that has been done on a light metal framed walls using all of the materials you suggest in a single wall assembly. The issue is the first material added to an assembly gives the best improvement. The 2^nd material is about ½ as effective as it would be if it was the only material used. If it is the 3^rd material, it usually ¼ as effective as would be if it was the only acoustic material unless it dramatically improves isolation damping or mass.

Example: MLV in a basic assembly can add up to 6 STC points-as a 2^nd material in an assembly it will add less than 3 points-as a 3^rd material it will add less than 1.5 points.

It would be good to compare the effectiveness of the individual materials in different wall assemblies.

1. An assembly with all of the materials
2. An assembly with isolation only materials (isolation clips) Isolation is the most effective single product.
3. An assembly with isolation clips and a (damping material) mass loaded vinyl on the opposite side of the wall from the isolation clips
4. Wall #3 with MLV replaced by double drywall on the opposite side with Green Glue between the drywall layers. This wall has isolation, damping and increased mass.

I would be surprised if the additional mass and damping of the MLV in assembly #1 would add enough acoustic material to increase the STC 1 point more than assembly #4.

It would be interesting to see the difference the performance between assembly 3 and 4; dB3 and Green Glue sandwiched between 2 layers of drywall are both combined damping and mass materials serving the same purpose.

To achieve STC numbers much over 60 usually requires double wall construction.

dB is impermeable. It will trap moisture. It must be placed to the warm side of the exterior wall so as not to trap moisture in the exterior wall. If it is placed on the exterior under the siding it will trap moisture in the space between the insulation vaper barrier and the dB material. Excessive trapped moisture will allow mold and mildew to develop in the exterior wall cavity.

If used on an exterior wall it should be in the drywall side of the wall.

dB3 can be painted with a primer and latex paint but I do not recommend it for 3 reasons:

1. It is class C fire rated so it will burn if exposed directly to flame.
2. Adding it on top of drywall does very little to improve sound reduction. The homeowner will get better performance adding another layer of gypsum. dB works best when installed inside of a wall where it can vibrate when exposed to sound.
3. Finish wall coverings must meet federal spec CCC-W-408 for flammability. dB3 does not meet the requirement for a finished wall covering for residential or commercial purposes. It must be covered by minimum 3/8″ gypsum or other fire rated finish wall coverings.

dB3, dB3 Max, and dB4 Max are UL listed for installation in all U300, U400 and V400 assemblies.

The UL certificate number is R-38761. See technical data for a copy of the listing.

The UL listing is for the United Stats only.

dB3 can be installed directly under ceramic tile for residential applications only. This will provide limited acoustic improvement

The dB3 must be glued to the subfloor. A rigid bond is required between the subfloor and the db3 is required. Premium vinyl flooring adhesive works well to create a rigid bond. Examples Armstrong S235, Stick-N-Stay-Lowes, Henry 695-Hardware Stores. 

Install tiles per tile manufacturer’s instructions.  Allow mortar to dry 48 hours before grouting. This is important for mortar curing; Grouted floors are to have no foot traffic for the first 24 after grouting and only light foot traffic for the next 48 hours. Grout cracking may occur if these instructions are not followed.  Mortar and grout continue to cure for up to 30 days.

IMPORTANT NOTE: Mortar or grout used MUST be polymer fortified; Recommended mortars are Mapei Ultra-flex 2 or Mapei Porcelain Tile Mortar. 

Mapei Flex Color CQ grout is recommended due to its high polymer content for crack resistance. Laticrete polymer modified mortars and grouts are acceptable. Custom Building Products, Flexbond Mortar and grout are not acceptable. 

The foil should face up to the ceiling cavity. The foil makes it a Class A fire rated material. Ceiling plenums in many commercial buildings require fire rated materials.

dB3 is designed for walls but it can be used on the subfloor under finished floor material. dB3 should be fully attached to the subfloor. 3M High Strength 90 creates a permanent Flexible bond. 3M HS 90 adhesive is available online and at big box stores.

In some cases, plasticizers in rubber and latex can react with the coating on vinyl floors in ways that discolor the flooring. PVC MLVs have plasticizers added to make it flexible. They can migrate out of the material over time and can cause discoloration of attached materials. dB3 is not PVC; it is made from POE (polyolefin elastomer), a naturally flexible material that does not require plasticizers. It does not contain plasticizers. 

dB3 has not been tested for compression resistance but its density is greater than rubber which is a common underlayment. dB3 is approximately 70% calcium carbonate (Crushed Limestone).

It can be, but the problem is building codes require wall finish materials to be tested for fire resistance if greater than 9mm or .036″ thick. This thickness allows the use of non-fire-resistant wallpaper.

The POE barrier side of dB4 and dB3 Max are Class C. Building codes require Class A. dB Lag is Class A; if the foil side faces out it can be left exposed.

In the application described Green Glue will improve the STC rating by about 3 points. dB3 will add 1-2 points. dB3 Max will add 3-4 STC points per our laboratory tests.

dB-4 Max does not support mold or mildew. If the laminate floor is installed correctly moisture should not be an issue. I recommend the dB4 Max be installed with the barrier side facing up and the seams and perimeter be taped withT-rex tape to inhibit water intrusion. T-rex is available at Walmart. Attach the dB4 Max to the cement board with 3M High Strength 90 to prevent the db4 Max from shifting under the laminate.

This is about the worst wall condition. It takes a combination of materials to reach an STC  50 wall using wood studs at 16″ on center.

Solution 1-gypsum-dB3-stud-insulation-resilient channel-gypsum

Solution 2-double layer gypsum-dB3-stud-insulation-double layer gypsum

Solution 3-gypsum-dB3-stud-insulation/-solation clips-gypsum

Building codes in high moisture locations may require a class 1 or class 2 vapor   retarder on the inside of exterior walls. dB3 is a class 1 vapor retarder. The dB3 acts as a very low perm vapor retarder. It is only recommended to be used on the inside side of exterior walls directly under the inside finish coverage for cold climates. If vapor barrier insulation is used the barrier side of the insulation should be placed directly against the dB3. In warm climates such as in areas near the Gulf of Mexico vapor barriers go on the outside of the wall to keep the moisture out of the wall cavity. MLV would go on the outside of an exterior wall in this case. The customer should check with the local building authority if they are unsure of which side the vapor should be placed on. On interior walls dB3 should be placed on the side closest to the noise to be blocked.

Unless LED lights are used the 2’ rule applies to all light fixtures. 

LED lights do generate less heat, but LED lights can reach 150 degrees F. We recommend they use double wall can lights for recessed spotlights. For all LED ceiling light fixtures lay 3 in fiberglass insulation over the fixture if recessed and install the dB3 over the insulation. The problem is not so much fire as temperatures around 150 degrees soften the dB3 causing it to sag. The insulation allows ventilation between the fixture and the dB3. Thereby reducing the temperature.

Acoustic or fire rated putty pads should be installed on the back of metal or plastic boxes installed in walls to prevent flanking noise going around or through the boxes. It is to be installed on the back and sides of the boxes. Putty pads have an STC rating of 40-46 which is much greater than the gypsum it is protecting. Covering the front of outlets will not improve the STC of the assembly unless putty pads are not installed on the back of the boxes.

For acoustic reasons it is not recommended to have electrical boxes on both sides of a wall in a single stud space. Electrical boxes, even when protected, may have openings around the wires which will allow noise into and out of the wall cavity. It is not unusual to hear noise or speech coming from an outlet or switch when boxes are installed on both sides of a wall in a single stud space.

dB3 and dB4 Max acoustic performance is similar. dB3 is designed as a sound blocker and dB4 Max is a combination blocker and isolator for low frequency floor impact noise.

dB3 Max is a combination of a heavy weight blocker with an isolation layer for low frequency sounds. dB3 Max is good for wall applications in theater rooms and industrial applications.

Yes, dB3 2 lb is recommended for utilization on a subfloor and covered with a layer of plywood. We recommend that the dB3 2lb be conditioned prior to final installation. Because the material is a thermoplastic a heat gun will help heat the material to facilitate proper fitment.

The final seams should be tight, and the underlayment should be glued to the subfloor.

The domestic content requirement of BABAA rises from 65% in2024 to 75% in 2029. The domestic POE and calcium carbonate content of dB3, dB3 Lite, dB3 Max, dB4 Max and dB Lag substantially exceed the 2029 content requirement.