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  • 1. IsoDamp Soundproofing System ARCHITECTURAL GUIDEASC ACOUSTIC S CIENCES CORPORATION4275 West 5th Avenue • Eugene, Oregon 97402Phone: 541-343-9727 • Fax: 541-343-9245www.acousticsciences.com © 2005 Acoustic Sciences Corp
  • 2. What is ASC’s IsoDamp System? Unlike other soundproofing systems, The key is separation of each layer of IsoDamp is based on the principle of wall sheathing from the wall framing IsoDamp Features Summary stopping sound transmission by ab- by WallDamp, an acoustic dampen- ☞ Absorbs sound and vibration sorption of sonic energy. Just like the ing material. Installation is easy and ☞ Very easy to install shock absorber in a car, IsoDamp is requires no special tools or skills. We ☞ Uses standard building materials designed to quiet by absorbing excess ship you a kit with everything you ☞ Versatile applications and uses sound. Many soundproofing systems need including complete instructions. available today seek to contain sound ☞ Superior to barrier systems instead of absorbing. While they work Basic Soundproofing ☞ Lightweight, 1 lb. per sq. ft. quite well containing, the excess sound is simply bounced around in Sound spends most of it’s time “flying” the room. It’s like driving around town through the air but sound in a room Most builders know to add interior with no shock absorbers, a pretty keeps on running into the surfaces of wall fiberglass insulation in order to rough ride in our opinion. the room. Each time sound impacts a add soundproofing. The insulation wall, floor or ceiling of a room, most reduces the build up of sound within All of our IsoDamp products use a of the energy is re- the air cavity of the walls. The less product we call WallDamp. This flected. But, not all noise there is in the air cavity, the less extraordinary material was first of it reflects, some noise is transmitted through the wall developed for use as a vibration of the energy is into the next room. Adding fiberglass damping material for multipurpose trans- to the wall cavity is usually done dur- industrial and automotive applica- ing construction. Basic batt insulation tions. Acoustic Sciences Corpora- or blown insulation is a good way to tion has been designing and testing retrofit a wall for some sound absorb- the use of this damping material in ing properties. modern frame wall construction as a noise and vibration damping in- Once the air cavity inside the wall is terface between building materials quieted down, adding more insulation for sound control projects. Wall- does not help make things more quiet. Damp has proven to be extremely This is because the sound you now effective for controlling unwanted hear is being conducted mainly from noise in structures where sound trans- mitted directly into the wallboard. the wallboard of one room through the mission is critical to the function of The wallboard is teeming with sound stud and into the wallboard of the next the building space. which can easily be heard by using a room. Adding WallDamp to the face mechanic’s stethoscope. Part of this of the framing, between the wallboard Besides it’s remarkable characteristics, sound, trapped in the wallboard leaks and the framing creates a sound attenu- it is easy to install by any commercial out of the wallboard and excites the air ating gap in the conduction path. What contractor or “do-it-yourselfer”. The inside the wall cavity. The remainder of fiberglass does for the air in the wall product comes with adhesive coating the sound is conducted into the wood cavity, WallDamp does for the wood on both sides and a paper backing stud to which the wallboard is nailed or or metal in wall framing. material to prevent contamination. screwed. In either case, the wallboard Application is purely a matter of “peel on the far side of the wall becomes ener- IsoDamp Soundproofing and stick”. gized and fills with sound as well. This When WallDamp is placed between excited wallboard then stimulates the the stud face and the wallboard, the Three Levels of IsoDamp air near the wall on the other side of the sound conducting path between the wall, transmitting the original sound into IsoDamp Ultra for walls and ceilings is two sides of the wall is disconnected, the new space. Sound “leaks” through our most comprehensive soundproof- interrupted by the thin layer of sound the wall two ways, by air borne conduc- ing treatment. This system uses resilient damping material. Like adding fiberglass tion and by structure borne conduction. channel plus felt perimeter gasket and to the wall cavity, adding WallDamp multiple layers of sheetrock. IsoDamp Standard uses multiple layers of sheet- rock separated by WallDamp. IsoDamp Economy will work with any standard stud framing system made of wood or steel. Apply WallDamp to all framing prior to sheathing. In each case, the goal is to improve acoustic qualities while reducing sound transmission. WallDamp blocks the sounding board effect, the conduction of sound right through the studs and wall cavity2
  • 3. to the framing faces dampens sound fundamental structural mode of vibra- A) Visco comes from the word viscos-transmission. This occurs in the higher tion. The entire wall shudders and the ity meaning how easily a liquid pours.frequency ranges of sound, the treble sound of the shudder is as loud in one For example, water is not viscous andrange. But there is more to the convey- room as the other. Adding WallDamp pours easily, but honey is a viscousing of sound through a wall than the air to the wallboard facing sides of the liquid and pours very slowly. A vis-and structure borne sound paths. Walls framing members causes damping of cous material absorbs energy whenvibrate. Whenever a wall vibrates as a this major mode wall vibration and it is forced to change shape. It takeswhole or in parts, sound energy rides improves it’s soundproof quality. work to deform a viscous material.the vibration right through the wall. Although it may be interesting that A lump of clay has much viscosity.WallDamp also controls the free vibra- the soundproof quality of a wall, it’s It takes work to change its shape andtion of the wall and puts a damper on resistance to being knocked on or then it holds that shape.these sounds vibrating through the wall. thumped is improved with the addi- B) Elastic means that something can beA wall is basically a sheet of thin wall- tion of WallDamp, such is not the deformed and it returns to its originalboard tacked to studs. The studs are usual reason for adding WallDamp. shape. A rubber ball is elastic becausetypically 16” apart. If the wallboard is It isn’t someone’s hand that is usually it returns to its original shape, even exciting the wall into a vibration, it is after bouncing off the floor. It takes work to deform an elastic material but the material is like a spring, and stores the energy. This is why a ball bounces back. A) + B) = C) Viscoelastic means it takes work to deform the object and BEFORE AFTER also that the object returns to its origi- nal shape. But, it just doesn’t springWallDamp quiets wallboard twang--the plate vibration of wallboard stretched across studs back like a rubber ball.tapped with the finger or rapped with sound itself that does it. For example, Example:the knuckle somewhere between the sound generated by the powerful If we have three balls, one of eachstuds, it twangs. The free vibration of loudspeakers found in today’s home type; visco, elastic and viscoelastic,that one section transfers across the theater, media and audio rooms. The and then we throw them one at a timestud to the next section and soon it subwoofer provides ample thumping on the ground, each behaves differ-is vibrating. Then the next section of energy and the regular speakers setup ently. The visco ball of clay hits thewall between the studs picks up the right next to the walls in today’s home ground and flattens out like a pan-motion and soon, the entire wall is theater systems provide plenty of cake. The elastic ball hits the groundquivering with the vibration. And the knuckle tapping energy. and bounces right back up off thevibration is conducted through the WallDamp Defined ground, as round as ever. The visco-stud and the air cavity to the wall- elastic ball however takes the middleboard on the other side which also WallDamp is a viscoelastic material. It road, it hits the ground and doesn’tvibrates freely at this same frequency. is not foam or vinyl, nor is it bitumi- bounce up but it also doesn’t flattenOne good rap and the entire wall nous sheet material. The concept of out, just sits there on the ground, stillbecomes engulfed in a twanging a viscoelastic material can be broken a completely round ball.condition. Certain tones are easily down into two parts:conducted from one side of the wallto the other side by this mechanism.Adding WallDamp to the wallboardfacing sides of the framing memberscalms down the wall twang, the platevibration effect, and improves thesoundproof quality of the wall.The wall as a whole is attached tothe upper and lower plates which arerigidly affixed to the other and moreheavy framing members. The midsection of the assembled wall how-ever is free to vibrate out and in. A BEFORE AFTERsolid thump with the tight heel of thefist will send most any wall into it’s WallDamp eliminates wall shudder--the structural vibration of the whole wall pinned between plates 3
  • 4. How WallDamp Works temperatures found in the walls, floors The Result and ceilings of places where people A wall, floor or ceiling is constructed You can get walls & ceilings that live and work and play. using a complex set of objects, each reduce sound transmission by 20dB or touching the other in some fashion. WallDamp may look simple but what greater compared to standard interior When any one piece moves, it pushes it does is complex and well suited to walls. That is more than quadruple the on the adjoining pieces and so on. its application in damping out the free perceived sound volume reduction, The reason WallDamp works is that vibration of walls, floor and ceilings. which is what makes our wall system it is located between all the pieces WallDamp is setting the new standard the highest available using standard so that every time one piece pushes in frame construction. And, once you single-stud construction. against another, WallDamp is there hear the difference, you’ll know what absorbing energy out of the push. you’ve been missing. Vibration Damping Undamped Vibrations - Vibrational energy is stored for a long period WallDamp Facts of time and can be retransmitted release paper • WallDamp is 1/16” thick. through other mechanisms. Example: an undamped room wall can vibrate • WallDamp has high strength adhesive perceptibly for more than one sec- • Strips are 1.5” wide x 48” long. ond when excited by sudden sonic • Squares are 4” x 4” impacts. This vibration then becomes WallDamp • Sheets are 24” x 48” release paper a secondary source of sound emitted back into the room, creating a source Actually, Walldamp does not absorb The Root of the Problem much energy when one piece pushes or pulls squarely on another piece. When a noise produces powerful It does absorb a lot of energy when low-frequency acoustic energy, that VIBRATIONAL ENERGY one piece tries to slide past the other. wave front travels through the room Fortunately when an object pushes and then collides with the wall, floor on another object, there is a strong & ceiling surfaces. Upon collision, tendency for the two to slip or slide a much of the kinetic energy of the bit at their contact point. This is where wave front is converted into mechani- Standard Construction WallDamp extracts the energy - from cal (vibrational) energy, which sets the the shifting surfaces. thin, flexible wall surface into vibra- tion. This vibration is easily conducted 0 1 2 The second thing about WallDamp is through solid surfaces it is in contact SECONDS that it has been made to extract energy with—such as the studs, joists and of unwanted lingering noise. This is from microscopic movements. That’s flooring. The vibration travels up and highly contrary to the desired acous- good because very small movements through the framing of the house—vi- tics of a well-developed sound room. are involved in the making of sound, brating the walls, floors and ceilings especially when it comes to surfaces as it passes them. What you get is a Damped Vibrations - Vibrational as big as walls, floors and ceilings. quaking house full of noise. This is energy is removed quickly, usually There are many kinds of viscoelastic what is known as Structure-borne through frictional losses, and is no materials. The most familiar is the Sound Transmission. The fact of the longer available to be transmitted. soft type that is put into the heels of matter is, conventional wall & ceiling This means that there is no secondary runner’s shoes to absorb the shock of construction methods easily conduct radiation of unwanted noise and is the the footfall. The deformation of this low-frequency sound, and are poor at desirable situation for preferred sound soft material is measured in fractions blocking them out. room acoustics. of an inch. WallDamp is relatively hard, but that is because the deforma- The Solution tion it has to process is measured in We have identified three ways to keep thousandths of an inch or less. The sound from traveling through a structure: VIBRATIONAL ENERGY hardness corresponds to the force and 1. Block the sound by increasing the the deformation involved. WallDamp mass (thickness & density) of the walls. is made for structural damping. 2. Minimize the transmission paths for Some viscoelastic materials soften and vibrations and sound to travel through. Standard Construction lose their energy absorbing power if 3. Absorb & Dampen vibrational energy. with WallDamp Added they get too hot. Similarly, if they get too cold, they harden up and lose Only Acoustic Sciences proprietary 0 1 2 their energy absorbing power. Wall- WallDamp incorporates all three of SECONDS Damp is specifically made for the these methods.4
  • 5. Everyday Use for keeping sound from getting out, but it’s bad for the person left in theStandard wall construction methods have room, the listener. If sound can’t getbeen providing some measure of sound Non-Damped out of a room it has to stay in the roomisolation for nearly 50 years. However, and reverberate. Carpet, draperies andpowerful low frequency sound genera- furnishings may provide some acoustic Noise Leveltors, the subwoofers found in today’s friction inside the room to attenuateHi-Fi and home theater systems, are sounds in the treble range but they sup-becoming much more popular. The rise ply little to no absorption for sounds inin at-home businesses has also increased Damped the bass range. That is why concretethe need for a quieter work environ- rooms are very ‘’boomy’’ sounding.ment, one which is hard to achieve withmodern building density as it is. Musi- When sounds or vibrations try to passcians, artists and the like, have, more 125 Hz 250 Hz 500 Hz 1 KHz 2 KHz 4 KHz through the walls, floor or ceiling of afrequently, begun to practice and record Frequency room, it causes those surfaces and theat smaller project studios located in structure behind each of them to move.their homes or other urban areas. Sound it works just as well in reverse. Loud When a wall, floor or ceiling vibrates,control issues generated in these circum- sounds from home theater and stereo it changes shape. The IsoDamp systemstances need to be addressed thoroughly systems, music practice rooms, or uses WallDamp to separate each ofto achieve their desired results and not workshops stays inside the house and the parts that make up the wall, floor out of your neighbor’s ears. Sound or ceiling. Any movement at all by the and vibrational energy within the wall, floor or ceiling causes a distortion house are also reduced. Wind can of the WallDamp. This distortion in the blow the front door closed without WallDamp absorbs the sound energy shaking the entire house. The sound and any vibration is quieted. power from the stereo or home the- ater stays in the room and doesn’t Broadband Soundproofing shudder the whole house. Kids can The addition of fiberglass to the wall play downstairs and the adults up- cavity only improves it’s soundproofing stairs hear almost nothing. Probably, performance in the upper frequency the best thing that IsoDamp con- range (tweeter range). Fiberglass has no tributes to today’s living experience effect on midrange or low frequency is the increased sense of peace and soundproofing. Despite it’s reputation quiet at a time when, day-by-day, in the construction trades for sound-interfere with their neighbors. IsoDamp more noise seems to be the only option. proofing, fiberglass in the wall cavityis not limited to only home-based noise provides but a fraction of the improve-control applications. It has become a Vibration Control ment available from the IsoDamp Sys-necessary addition to the construction of What is remarkable about IsoDamp tem. However, fiberglass in the wallprofessional and commercial spaces as construction is that it not only keeps cavity with WallDamp on the framingwell. sound and vibration from passing faces (IsoDamp Economy) is a one-two through the surfaces of the room but combination punch that is almost tooIsoDamp system construction is more that it actually absorbs it. By compari- simple to do, almost too easy to workresistant to the intrusion of external noise son, a concrete room is well known with and so very hard to beat.than standard building techniques, and IsoDamp Ultra IsoDamp Standard IsoDamp Economy Resilient Channel Felt Perimeter Gasket Standard Standard Greenboard Sheetrock Sheetrock WallDamp Greenboard Standard Sheetrock StripsBasic components of the three levels of IsoDamp Standard 5
  • 6. Vibration Control framing faces. This product can be In addition, STC is only a measure used for walls and ceilings, and is of how much vocal sound can be During testing, the inherent sound ab- great for improving the acoustic prop- stopped by a wall. But that’s not the sorbing properties of WallDamp with- erties of any room. end, it’s just the beginning of the in a standard framing system become story. The sound energy that gets evident. The graphic representations IsoDamp Economy is basically the stopped by a wall, doesn’t go through below show the paths and intensity of use of WallDamp strips to separate the wall, and that means it ends up sound transmission through framing staying inside the room. Now there is members in sur- too much sound lingering inside the face contact when Example of Wood Frame Sound Transmission Levels room, the lingering energy from one a source sound Before and After Applying IsoDamp System sonic event ends up covering over the was applied to the perception of the next sonic event. Sound Transmission Level (dB) test samples. 70 Ever heard of sound masking? 65 Before IsoDamp Three levels of Sound masking is usually associated 60 After IsoDamp system IsoDamp with a steady background noise be- are available, all 55 ing introduced so that people can’t of which feature 50 hear conversations across the room. WallDamp and Here, the masking energy is due to the the isolation- 0 0 50 90 0 0 0 0 0 80 25 16 lingering storage of high density, rapid 20 10 12 15 18 25 damping benefits Frequency (Hz) fire audio tracks. The audio, much associated with more than voice, tends to become it. The IsoDamp Ultra System is the framing from sheathing. This product self masking, and the higher the STC most comprehensive. To achieve is an acoustic enhansement that can becomes, the stronger the self masking maximum STC values, walls and be applied to one room, or the whole effect becomes. ceilings are suspended using damped house. With it’s “peel and stick” ease resilient channel. These are flexible of use, even a child can install it. It works the same way in high STC metal strips with added WallDamp, IsoDamp Economy can be used for rooms, where less sound is let out of which are attached to framing faces. walls, floors and ceilings, anywhere the room than is being delivered to At the floor, the drywall is floating on framing faces meet sheathing such as the room. A human voice can deliver bearing felt, and around the perimeter sheetrock or plywood. about 50 dB of continuous sound power. A movie sound track can de- Sound Transmission Without IsoDamp System Sound Transmission With IsoDamp System liver easily 80 to 90 dB of continuous sound power. That’s about 5000 times more energy than the human voice. If W allDamp wood this energy is held in the room by high framing STC walls, the sound quality inside nois e nois e s ourc e the room starts to become garbled. s ourc e In high performance audio systems, two things usually matter: Keeping sound from bothering the neighbors and getting clear sound inside the room. As you can see, the better the of the walls or ceilings, a gasket is STC, NRC and IIC STC rating, the worse the quality of used to help restrict even more sound sound inside the room becomes. What transmission. The pressure fluctua- Real world acoustics goes way beyond standardized lab test data. In particu- to do? NRC is the answer. tions from low frequency sound can still move the walls ever so slightly but lar, STC (Sound Transmission Class) What is NRC? now, when the walls move, they no can be very misleading, particularly in the area of high power audio ap- NRC (Noise Reduction Coefficient) is longer directly push the studs or joists. plications. To begin with, STC only the measure of the sound absorption Since movement of the wall doesn’t measures the the amount of vocal in side the room. STC measures how push the studs, it cannot transfer sonic range sound that is stopped by a wall. much sound is kept inside the room pressure pulses into the structure of Note that the VOCAL RANGE is a and NRC measures how much sound the house. fraction of the full bandwidth AUDIO is absorbed inside the room. A low RANGE played by most modern sound STC room leaks a lot of sound and to IsoDamp Standard is quicker and systems. STC does not really apply to maintain good sound quality inside easier to install, using WallDamp to today’s audio system. the room, to keep things from get- separate two layers of sheetrock from ting garbled, not much, a low NRC is6
  • 7. needed inside the room. But, like STC, high power loudspeakers. Our interior and the sheetrock and again between NRC is also measured in the voice wall does not store energy. A stan- the first and second layer of sheetrock. ranges. STC and NRC are both voice dard wall thunders when thumped. A range measurements, used for general standard “soundproof “ wall thunders IsoDamp FAQ architectural acoustics. They occupy even more when thumped. In high Q: Can I use different types and thick- the middle 6 octaves in the bandwidth performance audio rooms, thundering ness of wallboard than those listed in of human sensitivity to sound. Today’s walls are not acceptable. the instruction booklet? high power audio systems cover the full bandwidth range, 2 octaves lower Our interior wall is interlaced with A: Yes, but be sure to use different and 2 octaves higher than the vocal constrained damping materials, which types and/or thicknesses for each bandwidth. absorb structural vibration energy. of the two layers so that you don’t Our interior wall is light double-up on any natural resonances ASC IsoWall Gives Great Acoustics & STC enough to let some associated with a particular wallboard. deep bass pass right 70 Mass Loaded through it. But to do Q: I’ve heard you’re not supposed to 60 Bomb Vinyl so means the interior put moisture resistant wallboard on Steel Shelter Laminated wall is moved. And the ceilings. Is this true? 50 Sheetrock structural damping com-STC Rating IsoWall 40 pound takes over and Stud A: You can use MR board (green 30 Wall absorbs the energy right board) on ceilings as long as the fram- 20 Mobile out of the wall move- ing members are sufficiently close Home 10 ment. to one another. In the case of the IsoDamp system, the framing mem- 0 1 2 3 4 5 6 7 8 9 Final Thoughts bers for the wallboard are the resil- Bad Good One more thing about ient channels. If you are using 1/2” Interior Room Acoustic Quality high STC walls, they are moisture resistant board as currently very heavy. This means recommended in our instruction book- they don’t move. Rigid walls create let, then placing the resilient channels However, if the room has a high STC, strong and very frequency selective no more than 12” apart, as stated too much sound is kept inside the room modes. Our wall is “soft” and it in the ceiling instructions, is suffi- room and the room has to be “treated” does move. It is technical a membrane ciently close according to the 2000 so it has a high NRC, to get rid of the bass trap. Because it moves under bass USG Construction Handbook. If you stored sound so that the sound inside pressure it does not create a rigid walled are planning on using 5/8” moisture the room isn’t too garbled. room and the modes are not sharp and resistant board on the ceiling, then strong. When room mode testing is you will need to adjust your system to An extremely high STC room, an done in our high performance walled place the resilient channels no more underground concrete bomb shelter room, the “soft” walls act to diffuse than 16” apart to be sufficiently close. has a very high STC, over 100 dB. the modes, the room no longer has an Since the sound has nowhere to go, it acoustically fixed dimension. The room Q: The installation instructions require stays inside the room, lingering for 10 supports sound that has much longer that I attach the ceiling Perimeter to 15 seconds. Generally, a room has wavelengths that the physical dimension Gasket to the nailer plate above the to have an NRC of at least 15% to be of the room. This effect is very powerful top plates on the wall, but what if my acceptable for conversation. For high and makes for excellent listening. walls don’t have a nailer plate above power audio, the required NRC goes the top plates? up to about 40%. IIC (Impact Isolation Class)is the mea- sure of the resistance of a wall or floor A: In this case, you will need to place ASC’s Happy Medium Concept to conduct tapping or light hammering blocking between the ceiling joists at At ASC, we have developed the com- noise through the wall. Our structur- the perimeters of the ceiling. This will plete solution to high power audio ally damped wall are mechanically give you a continuous framed perim- room acoustics. The interior surface semi-dead, and they absorb tapping eter for attaching the ceiling Perimeter of the room is constructed with a me- energy. Next, our damped interior Gasket. dium STC surface, the type that best wall is connected to adjoining studs supports high power audio playback. by metal clips set on damping pads Q: Your instructions state that I should On the other side of this low STC wall which together act to greatly resist use insulation blanket with no paper surface, we apply a high STC rated conducting tapping sound, they have or foil backing. Why is that? wall surface to achieve the necessary a high STC to the conduction of tap- overall STC for the wall. Furthermore, ping sounds. And finally what little A: Two reasons. First, it is best to our interior wall is very unique. It is gets through and into the stud, if fur- avoid the possibility of the paper or “non-tympanic” in that it does not ther blocked by the structural damping foil surface ever coming in contact twang when excited, or hammered by sheets that interlace between the stud with the resilient channel. This could 7
  • 8. create a situation where there may still use your IsoDamp system? propriate adjustments to the resilient be a slapping sound heard from the channel spacing can be made to avoid vibration of the channel against the A: Yes, and, in fact, we can even help interfering with any junction boxes. thin membrane. Second, we want to make your cable pass-through better Built-in lighting on the ceiling can be keep the air-flow chamber as large as suited for use in combination with the addressed in a similar fashion. possible directly behind the wall. This IsoDamp system. allows deeper breathing ability and, Q: How can I further enhance my hence, greater overall effectiveness. Q: Can I use cement board or limp IsoDamp system? mass barriers with the IsoDamp system? Q: What if I need to have foil or paper A: Optional additional steps you can backing on my insulation or use a A: Yes, you can use more massive take are to: separate type of membrane as a vapor wallboard or additional layers of extra barrier? mass with the IsoDamp system. Be 1. Apply an optional IsoDamp appli- sure to place the resilient channel cation to the opposite side of the wall A: If you need to have a vapor barrier, more closely together to provide the (interior walls only) you have several options. First, if you extra weight support needed, if you do 2. Add ASC Stud Stabilizers to the can use insulation blanket with foil this. It is important to note, however, framework or stabilize the framework or paper backing, place the backing that the individual sound blocking by attaching it to concrete walls or away from the interior of the room abilities of different materials do not foundation (see the FAQ immediately above) for simply add to one another. For exam- 3. Use larger studs and joists and fill which the IsoDamp system is being ple, a layer of mass-loaded vinyl may the cavities with thicker insulation applied. If you must place the backing have an independent STC rating of (e.g. use 2x6 with 5” insulation fill vs toward the interior of the room, use 30dB and your existing wall may also 2x4 with 3” insulation fill) wire insulation supports to hold the have an independent STC rating of 4. Place your layers of wallboard backing at least 1 inch away from the 30dB, but when put together you will perpendicular to one another (i.e. put resilient channel. Second, if you need NOT achieve an STC of 60dB. Dou- one layer on vertically and the other to use a sheet of visquine or other ma- bling the mass of a wall will typically horizontally) terial to cover the entire wall, place it increase the soundblocking power by 5. Use a staggered stud or double stud on the opposite side of the frame from 2 to 4dB. So, for the previous example frame design. the side for which you are applying the resulting STC would most likely 6. Use ASC Wall Wool Batts in place the Iso-Wall system. If you must place fall between 32 and 34dB. of standard fiberglass insulation. the material on the interior side of the frame, place it separately over each Q: How do I build light switches and Q: Can I put the IsoDamp system on stud cavity, tucking the edges into the electrical outlets into the IsoDamp the floor? interior of the cavity and attaching it system? to the sides of the studs . This leaves A: Yes, IsoDamp Economy can be the stud faces exposed for placement A: Every room has its own unique used on floor joists. To further im- of the Iso-Wall system. Be sure to tuck configuration and we defer the exact prove sound blocking power through the material far enough into the cav- solution to the expertise of the on-site the floor, you should apply the Iso- ity so that it is no closer than 1 inch builder/contractor. Electrical outlets Damp Ultra system to the ceiling in away from the resilient channel at any usually occur around 10” off the floor. the space below. If you wish to add point (see FAQ immediately above). This places them between the bottom a floating floor or riser to the room, If you are applying a vapor barrier to and the second resilient channel up contact us for more information. conform to building code, you may from the floor. You should offset junc- be able to get the IsoDamp system tion boxes to take into account the ad- Q: Can I use a layer of Plywood in the itself to be considered an acceptable ditional thickness of the resilient chan- walls with the IsoDamp system? vapor barrier by your building inspec- nel and 2 layers of drywall, as well tor. If you are using the 2 layers of as the small thickness added by the A: It is OK to use plywood as the first wallboard, including moisture resis- layers of WallDamp material, making IsoDamp layer. Apply WallDamp tant board, 1/2” gasket, and acoustic the total wall thickness in the range as usual. We normally prefer using sealant as directed in the installation of 1-3/4 inches. It is recommended sheetrock because it is heavier than instructions, you have built an air/ that you leave a 1/4” gap between the plywood of the same thickness which moisture-tight seal on that surface. edge of the box and the wallboard that allows the possibility for greater mass This is what is required for an accept- should be sealed with acoustic caulk, in a smaller space. able vapor barrier. identical to the edges of the wall. Face plates can be screwed tightly to the Q: I have a recording studio and I boxes once the caulking has had suf- want to have a cable pass-through ficient time to dry. For light switches, built into the wall. Can I do this and you should plan ahead so that ap-8