QuietRock vs Double Drywall: Which Is Better for Soundproofing?

Are you like me and trying to choose between QuietRock vs double drywall to soundproof walls and ceiling in your media, games or bedroom? Determining which will give the best results for the price can be difficult.

Which Is Better for Sound Reduction? QuietRock or Double Drywall? QuietRock can improve the soundproofing by 15 to 20 points on the STC scale, while it will take up to four sheets of drywall to have the same effect. If you’re doing both sides of a partition wall, that’s 2 sheets of QuietRock for 8 of the gypsum.

 In this article, I’ll take a look at QuietRock and compare its installation and soundproofing with regular drywall. I’ll also look at the similarities and differences of soundproof with QuietRock vs. double drywall.

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Quietrock vs Double Drywall

What is QuietRock Sheetrock?

QuietRock is a sound damping product that has a viscoelastic material sandwiched between two gypsum layers. The gypsum has the mass to block soundwaves, and the viscoelastic material damps the wave vibrations. Combined the sheet will reduce the transmission of sound in or out of a room by between 15 and 20 STC points when compared to standard drywall sheets.

The sheets are available in thicknesses of 1/2″, 5/8”, and 1-3/8”, with dimensions of 4’x8’, 9’, or 10-feet. The lengths are tapered for taping and mudding, plus it can be scored and snapped the same as regular sheets. The 5/8” 4×8 sheet weighs 83.2-pounds (2.6 lbs/ft²). Prices of building materials like drywall and QuietRock fluctuate, so check with suppliers for current prices.

Types of QuietRock Panels

EZ-SNAP ($60-$65)

5/8” thick 4×8’, 9, or 10’’ sheets that score and snap easily, and can be used the same as standard drywall, but with better soundproofing performance. The panels attach directly to the studs or joists, so takes up less space than other standard drywall attenuation techniques. A 4×8 sheet weighs 83.2-pounds and has an STC value between 48 and 60 depending on wall construction.

EZ-SNAP Mold Resistant

Similar to EZ-SNAP but with mold-resistant paper and soundproofing core material. A 4×8 sheet weighs 83.2-pounds and is ideal for damp locations or bathrooms. Depending on wall assembly, it has an STC rating between 48 and 60.

QuietRock 510 ($55-$60)

A less expensive option, the 1/2″ thick 4×8’, 9, 10’ and 12’ gypsum panels also have a sound damping core. They can be installed directly over existing drywall to improve STC rates to between 47 and 52.

QuietRock 530 ($105-$110)

A denser 5/8” panel available in 4×8’, 9’, 10’ and 12’ sizes, and the 4×8 weighs 105.6-pounds (3.3 lbs/ft²). It is shear rated for almost 500-pounds and has an STC 52 and 74 depending on the construction methods used.

QuietRock 530 RF

The 530 RF is the same as the 530, but with added shielding against radio frequency penetration to provide high security for information-sensitive locations. Installation requires different preparation to ensure the radio frequencies are blocked, and a skill saw to cut or trim. It is impact resistant and can be used on walls, ceilings, and floors for full protection and STC rankings between 52 and 74.

QuietRock 545

An 11 layered high-performance drywall panel that is recommended for home or commercial studios, sound rooms, or theaters. The 1-3/8” thick 4×8’ sheets are a hefty 200-pounds (6.25 lbs/ft²). They have tapered edges and are STC rated between 60 and 80 depending on wall construction. 545 works well even on low-frequency noise too.

Benefits

The benefits of using QuietRock over other drywall products are many. Layer to layer it provides better sound attenuation, which reduces the need for additional layers, resilient or hat channels, and viscoelastic material. Time and budget constraints are additional savings as a wall can be finished in one pass, instead of multiple passes for different layers of material.

A single layer of QuietRock also means you don’t give up floor-space to additional layers too. The panels finish the same as regular drywall, have an equivalent fire and smoke rating, but reduce noise transmission better.

STC ratings

The sound transmission class (STC) is third party verified, so it isn’t skewed like some big companies do. The STC ratings are based on wall construction, not individual panels. That means to achieve comparable values; wall construction needs to be similar. The Product Datasheet for each QuietRock product provides images of the wall assemblies and the STC. It is also recommended that soundproof caulking be used to seal the 1/4″ gap left where the wall meets the ceiling, floor, and other walls or openings.

Fire Rating

QuietRock is fire rated similar to regular drywall compositions; one-hour rating for 5/8” sheets, the 1/2″ thick 510 panels have not been tested for a fire rating. I also couldn’t find a rating for the 1-3/8” thick QuietRock 545. However, I presume it would be equal or better than the 5/8” rating. When gypsum is heated to high combustible temperatures, it will produce steam as trapped moisture evaporates.

QuietRock on Ceilings

Quiet rock can be used on ceilings to block airborne sound. Like most other drywall material, it doesn’t handle impact noise isolation. QuietRock can be attached directly over existing drywall that is attached to the joists, not to resilient channels. It also should be screwed through the existing gypsum layer and into the joists. QuietRock does not recommend the 510 product for use on ceilings due to the possibility it may sag.

Where to Buy QuietRock

The QuietRock website has a dealer locator for a location near you. The dealers may have some products in stock but not the whole product line. You will most likely need to order in depending on product, dimensions, and the number required.

QuietRock Installation

The installation of QuietRock is similar to that of regular drywall in standard applications. It should be fastened directly to the studs or to existing drywall with appropriate screws. Leave a 1/4″ between the panels and the ceiling, floor, and adjacent wall to be filled with acoustic calking.

QuietRock has a viscoelastic material inside it which damps vibration. For partition walls with 3.5-inches of insulation and wood studs every 24-inches, an STC rate of 51 can be achieved using EZ-SNAP, and an STC of 52 with QuietRock 530. Using the same insulation but with 3-5/8” steel studs at 24” centers instead, and the STC climbs to 55 and 56 respectively.

QuietRock 545 on a single stud wall has an STC rating of 56. Decoupling the wall with a double-thick stud wall and 545 takes the value to 75. Doubling up the 545 on that type of wall construction produces a quiet value of 80. However, you’re also losing 2-3/4” off the perimeter of the room.

Pros 

  • One 5/8” layer provides sound stopping results
  • Saves on labor and material costs
  • Heavier, so more sound stopping mass
  • Better STC values than regular drywall on similar wall construction.

Cons

  • Expensive
  • Difficult to use for ceilings
  • Not good for decoupling and blocking mechanical or impact noise

Types of Drywall

Drywall is sheets of gypsum wrapped in paper and commonly has tapered edges on the long sides for tape and mudding. It is known by different names and brands, such as wallboard, gypsum, gypsum board, plasterboard, and Sheetrock – which is a brand name. Different thicknesses are available for specific uses and products. The thicker materials are denser and offer more mass, which helps decrease sound transfer.

Regular or White Board drywall panels are available in 1/4” to 1” thicknesses, and 4×8’, 9’, 10’ and 12’ dimensions. Longer sheets can be special ordered. The paper on the room side is whitish, and the back, or wall side, is brownish.

Green Board is a moisture-resistant gypsum sheet. The green covering is more impervious to moisture. It isn’t waterproof but is frequently used as a backer for tiles in bathrooms, kitchens, and laundry rooms.

Blue Board is more water and mold resistant than Green Board, and is often used for plaster finishes. It has special absorption properties for use with plaster finishes; the paper isn’t made for taping, mud, or paint.

Paperless Gypsum is covered with fiberglass instead of paper and resists moisture, mold, and mildew much better. The fiberglass covering isn’t smooth, so a slick coat of joint compound is required for a smooth paint finish. The boards are also more durable than the paper coated gypsum.

Purple covered gypsum panels are similar to regular sheeting but have better moisture and mold resistance. It is ideal for basements or bathrooms where water contact is likely.

Type X is made with non-combustible material and is referred to as fire-resistant. To be fire-rated a 1/2″ thickness must achieve 3/4-hours of fire resistance, and a 5/8” thickness an hour. Required by building codes for specific locations, it commonly is used in apartments, schools, meeting rooms, and garages.

Soundproof drywall sheets have a layer of sound stopping material sandwiched between two layers of gypsum. It is denser than comparable thicknesses and blocks more sound movement. Frequently used in media rooms, or rooms requiring less noise intrusion or disruption.

STC ratings

For comparison with the QuietRock, the wall assemblies are the same. A wood stud wall with regular 5/8” drywall and 3-1/2” of insulation has an STC of 46, with steel studs that will improve that to 49. Doubling the drywall on steel studs brings the STC to 58, plus it doubles the fire rating to 2 hours. Doubling the drywall on wooden studs with insulation has an acoustic performance of 52 and two hours of fire rating.

Drywall with Green Glue Assemblies

Using Green Glue to damp sound requires two layers of drywall. The first layer of gypsum is attached to the studs. A coating of Green Glue is applied to the second sheet of drywall before it is attached to the first. Offset the seams of the second layer from those of the first, and to screw to the drywall, not the studs. The “glue” is compressed between the two layers and forms a spongy layer that absorbs sound vibrations.

Double Drywall benefits

The benefit of a double thickness of drywall with Green Glue sandwiched between is less noise penetration. The drywall adds mass, which prevents sound wave penetration, especially lower frequency, and the Glue absorbs sound vibration-damping sound vibration movement. 

QuietRock vs Double Drywall Comparison

When soundproofing a room or space, remember that the aim is to decrease the transmission of sound into or out of a room. It won’t be soundproof; it will hopefully be quieter. Whether renovating or building, the cost is always a factor, as is time – which is also money. Adding QuietRock over an existing layer of drywall will add to the mass and reduce sound transmission. It will improve the STC value by about 5 points. Drywall addresses the mass requirement, and works best for airborne sound, not impact or flanking noise.

The cost of 5/8” QuietRock EZ-SNAP is $60 to &65 for a 4×8 sheet, and 530 is $105 to $110.

The cost of 5/8” regular (non-light) drywall in my area is $12.57, so 2 sheets will cost $25.14.

A 5-gallon pail of Green Glue is about $260 and will do 365 square feet, or just over eleven 4×8 sheets, so about $23.60 a double panel.

The math works as follows: $25.14+$23.60=$48.74 for a 4×8 section of wall using double drywall vs. $60 to $110 for a layer of QuietRock. The sound transmission class ratings are compared in the table.

For a 10ft by 10ft room, the costs for doubled 5/8” regular drywall and Green Glue would be $487.40. The same room in one layer of either EZ-SNAP or QuietRock 530 is between $600.00 and $1,100.00.

 

Assembly STC
2×4 Wood Stud Partition Wall (24” spacing) With 3-1/2” Fiberglass Installed
1/2-inch layer drywall on each side (1.6 psf) 42
1/2-inch QuietRock 510 panel installed vertically on each side (2.1 psf) 52
1/2-inch double layer (1” thickness) drywall on each side (3.2 psf) 46
5/8-inch layer drywall on each side (2.3 psf) 48
5/8-inch layer drywall on each side with resilient channel 51
5/8-inch EZ-SNAP QuietRock panel installed on each side (2.6 psf) 51
5/8-inch QuietRock 530 panel installed vertically on each side (4.1 psf) 52
5/8-inch double layer (1-1/4” thickness) drywall on each side (4.6 psf) 54
5/8-inch double layer (1-1/4” thickness) drywall on each side with Green Glue 59

How to Improve Acoustic Performance

Making a room quieter means addressing the four elements of soundproofing – absorption, damping, decoupling, and adding mass. Drywall with Green Glue and QuietRock add mass and damping and address airborne sound. They don’t address mechanical (impact) or flanking noise. Check out How to Soundproof a Ceiling, and How to Soundproof Walls for further information.

Outlets, switch boxes, light fixtures, and vents are possible ways for sound to by-pass your drywall soundproofing efforts. Frequency vibrations can bounce from room to room unless they are damped too. Putty pads are a viscoelastic material that can be used to wrap electrical boxes and vents to quiet noise transfer.

Acoustic caulking is another way to damp vibration movement. There should be a gap between the drywall and the floor, ceiling, and adjacent walls. Filling the gaps with the caulking helps prevent sound movement.

Resilient clips and channels are an effective way to decrease vibrational sound waves by decoupling the wall layers. Use of resilient clips and channels can improve the STC by between 12 and 15 points.

Conclusion

Reducing the sound disruption in your home or business is a matter of controlling the four elements of sound – adding mass, damping, absorption, and decoupling. Adding fiberglass or rock wool between the studs adds absorption, and double-drywall with Green Glue or QuietRock add mass and damping.

QuietRock will take up 5/8” of floor space while double-drywall uses 1-1/4”, so if space is a factor and cost isn’t, then I’d recommend the QuietRock. However, the STC improvement between a single layer of regular 5/8” gypsum and the EZ-Snap is only 3 points, which in the world of noise, isn’t much. If you are serious about stopping the sound, doubling the drywall and adding a viscoelastic material like Green Glue, bump it 8 to 11 STC marks. Now that is sound stopping!

Hope you found this article of value. If you know someone who might benefit from it, pass it on. Your comments and suggestions are always appreciated.


Eugene Sokol

Hi, I’m Eugene. I work with noise all day, so I enjoy any peace and quiet I can find. I began looking at ways to improve the sound quality of my home and to make a soundproof office for myself. As a DIY enthusiast, I looked for solutions I could do. I created this blog to share what I learned and to make it easier for you to improve your quiet space too.


38 thoughts on “QuietRock vs Double Drywall: Which Is Better for Soundproofing?”

  1. I really appreciate your research and valuable information! I am still not sure the best solution to dampening/eliminating the droning, vibrating sound coming through my walls on one side of my condo. The building has the air condition units mounted to the roof which sends the vibrations through my walls whenever other units run their air or heat. Maybe a combination of methods?

    Reply
    • Hi Laurie,

      Adding 5/8″ drywall with Green Glue sandwiched between will certainly help because of the mass. You may also want to give some consideration to decoupling because of the vibration. Resilient channel or isolation clips and hat channel applied to the existing drywall, then covered with 5/8″ drywall. this will give you the mass for dampening and the decoupling to cut down vibration. (The resilient channel will add about 1″ to the wall. Clips and hat channel will add over 2″.) Whichever method you choose, you will have to extend plug, switch and light boxes. While doing that, make sure you close off the gaps between box and drywall with insulation, spray foam, or caulking. Noise loves gaps and holes.

      Hope that gives you another option,

      Terry

      Reply
    • Hi Steven,

      Your biggest problems with old lath and plaster are: 1) You probably have cobwebs for insulation and 2) The plaster is the consistency of concrete that might have to be drilled before you can screw into it. So just hanging drywall of any type can be a challenge. And tearing it down is usually a horror show. I might give some consideration to putting up Mass Loaded Vinyl, then strapping the walls with 1 x 3, installing 2″ Roxul, then any kind of drywall finish you prefer. If you need great soundproofing, building a room-within-a-room is the answer. I have an article coming out in a couple of days on the subject. You might want to check it out.

      Hope that helps,

      Terry

      Reply
  2. Hi Terry-

    Thank you for your post-it was very helpful! I’m building an indoor basketball court (50 X 26 ft with 18 ft ceiling) that shares an existing exterior wall with the rest of our home and is on the basement and ground floor level. I’m concerned about reducing the echo and noise inside as well as soundproofing the existing wall shared with our home so that we don’t hear bouncing balls and voices. I am going to use your recommendations of drywall, green glue, and isolation clips to help with noise traveling from the court, but would like your opinion on reducing noise within the court. We will be using a high-impact polypropylene copolymer tile with acoustical underlying on the floor. Any ideas for us? Thank you!

    Reply
    • Hi Marilyn,

      You could try a combination of sound absorbing blankets and acoustic foam panels. USCargoControl makes an 80″ wide x 96″ high heavy blanket with grommets for hanging. Use them on the bottom of the wall from floor to 8′ high. Then I would spot position Little Lucky 2″ acoustic foam panels on the upper portion. You can always add acoustic panels as required, but I think covering about 30% of the wall will diffuse and absorb enough sound to make it acceptable. If you want to get really creative, hang a few sound diffusers on the upper wall also. You may want to look at our article ‘How to Sound Treat a Room‘ for more information.

      Hope that helps,

      Terry

      Reply
  3. Hi,
    Good article laying out the differences. I would be interested as to your source for your STC ratings in the chart.

    Regards
    Gary

    Reply
    • Hi Gary

      For STC ratings go to quietrock.com/products/quietrock-530 Click on Product Data Sheet. For double drywall go to STCratings.com/assemblies.html

      Terry

      Reply
  4. The cost calculation for using green glue is notably lower than it should be as your price for a 5 gallon bucket is over $100 less than any GG provider that I can find. It is priced at ~$360 delivered at best. Plus you need an applicator gun which is another ~$75+, something that you need multiple buckets to justify.
    So your price of “$250” is actually closer to $425 for a single 5 gallon bucket of GG.
    If you happen to have an amazingly cheap supplier please let us know so we can order from them!

    Reply
    • Hi Curtis,

      I did a quick check and the best price I could find was $314.00 plus the gun at $75.00. Not sure if we made a typo or found a sale that day. But you are correct. Price is closer to $400 than $250.

      Sorry for the confusion.

      Terry

      Reply
      • Hello Terry,
        We will be adding drywall to existing walls in a bedroom. We will also be adding Endow window inserts to the windows (storm windows). By doing both we are hoping to get a 10 decibel reduction in sound. My question, is there any benefit to adding QuietRock drywall over the pre-existing drywall Versus standard dry wall? We do feel very slight vibrations in the room. Thank you and my apologies if you already this question. Teresa

        Reply
        • Hi Teresa,

          Standard 5/8″ drywall with Green Glue sandwiched between the layers will do a good job of adding mass and damping sound. QuietRock is better, specially with Green Glue, but it is three to four times more expensive. I am not sure that the storm windows will do what you want unless they are laminated glass. You could also consider Shut-Eye shutters which reduce noise by 25 – 50 decibels or AcousticCurtain which reduce noise by 21 – 25 decibels, for the windows.

          Hope that helps,

          Terry

          Reply
  5. Hi,
    We are in duplex and single connect wall with tenant, we wanna make this existing wall sound proof. will you describe the best option for us? and do we need any expert to do this project?

    Reply
    • Hi Khush,

      The best way to make the wall soundproof is to build another wall. Please see our article How to Build a Room Within a Room. That will get you as close to totally soundproof as possible. If you want to quiet it down, you can hang sound absorbing blankets or Nicetown soundproof curtains on the wall using self-adhesive hooks instead of curtain rods. Another option is Mass Loaded Vinyl which can be painted. (All of these are available on Amazon.) None of them will make it totally soundproof but will certainly dampen the noise quite a bit. As for needing an expert, it depends on your abilities. If you are fairly handy, you can do most of this yourself–including building a wall. If not, you might want to talk to a contractor or three who have done some soundproofing work.

      Hope this helps,

      Terry

      Reply
  6. Hi,
    Your article was very insightful and in the last paragraph you state the following:

    ” If you are serious about stopping the sound, doubling the drywall and adding a viscoelastic material like Green Glue, bump it 8 to 11 STC marks. Now that is sound stopping!’

    Before I invest in the drywall, please confirm that two layers of regular drywall sandwiched with green glue is just as effective as the expensive Quietrock?

    Also I can’t seem to find the Certain Silent FX drywall anywhere not even Lowes who the manufacturer claims carries it.
    Thanks

    Reply
    • Hi Everett,

      Double 5/8″ drywall with Green Glue sandwiched between should be just as effective as one layer of QuietRock. The manufacturer of Silent FX is Certainteed not Certain.

      Hope that helps,

      Terry

      Reply
  7. Having read your blog and the comments, my question is whats the best solution for me to soundproof my bedroom ceiling, the green glue and drywall? My ceilings are 9 foot so it would be doable. My neighbors living space is directly above my bedroom!

    Reply
    • Hi Cindy,

      If your ceiling is textured in any way, Green Glue will not work without scraping it down to smooth drywall. The glue has to be in contact with both surfaces to dampen noise. For extra soundproofing you can decouple the new drywall from the existing using either Isolation clips and hat channel, or Resilient channel. If you decouple the ceiling, then install either QuietRock or double 5/8″ dry wall with Green Glue sandwiched between, you should have a more peaceful environment.

      Hope that helps,

      Terry

      Reply
  8. Dear All,

    I plan to knock out the existing drywall that will be replaced by QuietRock wall (530) to block the elevator noise. Could you please tell me what are the right procedures to get the best sound reduction?

    Many thanks,
    Senqui

    Reply
    • Hi Senqi,

      Take off the existing drywall, use acoustic caulking to seal any holes and gaps (including the sill plate to the floor, insulate the stud cavities with Roxul 80 rockwool, hang Mass Loaded Vinyl on the bare studs, then install the QuietRock. Should quiet things down quite a bit.

      Terry

      Reply
  9. Wow, amazing post. Covers so many unanswered questions I have had from trying to understand how different elements of soundproofing works together.

    Would love to get your opinion: with the goal of just dampening adjacent room loud conversation and reasonable TV/music sound, and if we don’t have the ability due to cost/space to do resilient channel, hat clips and such, will doubling up on 5/8” drywall on one side only on the shared wall (but not the other 2 interior walls that open to an open hallway space and other open space) make an appreciable difference?

    Or would not doing the non-shared walls negate any benefits of the double drywall? This is steel stud construction which I understand will already offer some improvement over wood studs.

    Reply
    • Hi Steve,

      Drywalling one side will be helpful. Adding Green Glue sandwiched between the layers will be even better. Put the new drywall on the noisy side to keep sound inside. You could also consider foam acoustic panels and diffusers in that room to keep the sound in.

      Terry

      Reply
  10. Terry,
    After a few days of research, I feel less confident that I can solve my sound/vibration issue without trial and error which isn’t cost effective or a good use of time. I have mechanical equipment (wall mounted on-demand boiler, circ pumps, valves, and enough copper to circle the globe) in the garage with a bedroom on the other side of that common wall. The wall has 5/8 Type-X on the garage side, 2×6 studs, R19 batt, and 1/2” rock on the bedroom side of the wall. In the bedroom, the humming/vibration, and sound is mind numbing when the system is running. I would prefer to leave the existing wall alone as the garage side has most of the equipment mounted to the wall. With that said, I would greatly appreciate your thoughts on how to best tackle this issue. I live in Alaska, where we don’t have companies that specialize in sound proofing. I have in-floor radiant heat buried in 1-1/2” gypcrete floors so nailing into the floor is not advisable (for adding a second wall). A second wall seems to be the best choice but how do I secure it to the ceiling and side walls without the possibility of transferring sound/vibrations? If I use MLV, along with green glue, acoustical caulking, and another layer of 5/8” make enough difference? I believe I can purchase quietrock locally but I will need to verify that next week. Anyway; thanks for any help you can provide. Travis

    Reply
    • Hi Travis,

      The second wall is probably your best bet. Here is how I would build it:

      Snap a chalk line about 5″ inside the existing wall. This is inside of your new framing. Glue BXI Anti-Vibration Pads @ 16″ on center on the floor (Liquid Nails) and ceiling. Use 3″ drywall screws to hold the ceiling pads in place until glue sets, then remove them. Glue a 2 x 4 sill plate onto the floor pads. Apply glue to the ceiling pads and wedge your top plate in place. When everything is dry install your studs–preferably at each pad location. Cut them about 1/8″ long and tap into place. (Even 1/8″ might be a little long. The pads do not compress very much. Use 3″ deck screws to attach studs. Hammer and nails or a spiker tends to loosen things up.

      Insulate with Roxul 80 Soundproofing Rockwool, drywall and finish. Do NOT attach new wall to existing wall in any way. You might want to check out our article How to Build a Soundproof Room Within a Room for a few more ideas.

      Hope that helps,

      Terry

      Reply
  11. Hi. As everyone else has stated, thank you so much for all the wonderful information. I have the same problem as the last comment above. However, I cannot double drywall the noisy side. Therefore, is the double drywall with the green glue in between still going to do the job on the side where the noise is not coming from.

    Reply
    • Hi Janelle,

      Yes, it will help quite a bit because of the extra mass and sound dissipation quality of the Green Glue. Noisy side is always better, if possible. But if not, you will still notice a big difference by working on your side of the wall. You can also give some consideration to either Resilient Channel or Isolation Clips and Hat Channel before the new drywall is installed, to decouple the walls. It will add an extra 3/4″ – 2″ to wall thickness.

      Terry

      Reply
  12. Great info. Question: I have an office space that has a shared wall. We are looking to convert it to a recording studio. I had an engineer tell me about adding drywall to the existing wall with a gap in between then adding an additional drywall. So not doubled together but doubled with about a 2-3 inch gap in between. Would that significantly decrease sound transmission?

    Reply
    • Hi Herndon,

      Sounds like he is recommending decoupling the wall, which is one of the best ways to quiet a room. Hopefully he is using resilient channel or isolation clips and hat channel. (Both available at Amazon.) If he uses either product, then double 5/8″ drywall with Green Glue sandwiched between them, it should be awful quiet.

      Terry

      Reply
  13. Hi Terry,

    Thanks for such an incredible post. I have a basement suite that I will be renting out, and our baby room and main bedroom are directly above the main room and living room downstairs. I want to try and remove as much airborne noise as possible as voices can be heard pretty clearly between floors.

    We have central air, so there’s definitely noise transfer through the vents, as well.

    I’ve spoken to several contractors and I’ve been given a few recommendations.

    1) cut incisions into the existing ceiling and use spray in foam – I’m hesitant about doing so cause I feel like a lot of gaps could be missed.

    2) install carpet upstairs over the hardwood. + Spray in or additional layer of drywall

    3) gut the ceiling entirely, lay two layers of roxul, and add 2 layers of 5/8. This is a fair bit out of range for me budget-wise.

    4) block off the vents with roxul in conjunction with one of the other methods. We will be installing baseboards anyway, but it’d be preferable to keep the shared heating.

    What do you recommend would be the best way to significantly dampen the baby noise without going broke, haha.

    Also, do you have any recommendations on how we could reduce noise between the vents without blocking them off entirely or replacing them?

    Thanks so much.

    Reply
    • Hi Datis,

      1) Do NOT use spray foam. It is great for insulating but not very good at soundproofing. If you can find a contractor to blow loose cellulose insulation in the cavities, you are way better off. All it takes is a small (2″ x 2″) hole in the drywall, a long hose, and someone who knows how to turn the air down and patiently fill the cavity. You can do it yourself by buying the product from Home Depot or Lowes, and renting a machine from them.
      2) Installing heavy wool carpet will help a lot. For extra soundproofing install QuietWalk Plus (Amazon) first. See our article Best Soundproof Underlayment.
      3) If you add the carpet upstairs, you should be able to just add one layer of 5/8″ drywall with Green Glue sandwiched between the old and the new. (Existing drywall needs to be smooth–not textured for Green Glue to work properly.)
      4) Blocking off vents is NEVER a good idea. It can overload your heating system, shorten its lifespan, and possibly cause a fire. If you can position heavy furniture or book cases over, or in front of the upstairs vents and still allow air movement, that will absorb and deflect some of the sound.

      Hope that is helpful,

      Terry

      Reply
  14. Thank you for the informative article. I learned a lot.
    I read on the Quietrock website their suggestion to add their version of Greenglue (Quietglue Pro) between the Quietrock and an existing drywall for an additional 3 STC. Does that make sense to you? If so, would using Greenglue compound be more effective than Quietglue Pro.
    Thank you.
    Patrick

    Reply
    • Hi Patrick,

      Sorry, I do not know anything about Quietglue Pro. If I were to guess, it is probably much the same as Green Glue, otherwise they would not advertise it. Green Glue has been the most used product for years–because it works as claimed.

      Terry

      Reply
  15. Thanks for the great article.

    I have a first floor “home office” space that I would like to better sound deaden. Currently the “noise” comes from the ceiling above from family members walking on the hard wood floors that do have rugs (my house is 3 stories with the office located on the first level) and the second place where the sound comes through is one wall. The existing ceiling does have a light texture on it as well as two hfac vents, one ceiling fan and two recessed light fixtures. The wall that also has a light texture on the drywall.

    Would you suggest sanding the drywall and adding an additional layer of drywall to the ceiling with green glue in between the drywall? The same with the wall?

    Thanks very much

    Reply
    • Hi Brian,

      I assume it is not popcorn texture that just scrapes off. Sanding a ceiling is not much fun. You might want to give some consideration to 5/8″ QuietRock. QuietRock is made of 2 layers of drywall with a viscoelastic polymer sandwiched between them which performs like Green Glue. (For more information see this Wikipedia article.) If the ceiling is fairly smooth this should work. If not, you could strap it with 1 x 2, or for extra decoupling use Resilient Channel.

      Terry

      Reply
  16. Want to soundproof the outside of a wall next to a busy intersection, where acceleration noises are very high. Now there is only a “thin” decorative panel over 6″ wall studs with fiberglass insulation. What about 1/2″ OSB with painted cuts and surfaces for water proofing, nailed directly to studs, green glue MLV to that, then green glue decorative panel to MLV and offset-screw decorative panel into OSB? Will it reduce the noise significantly, or are there better alternatives, keeping in mind I want to keep the cost low and the wall and windows to look like the original as much as I can..

    Reply
    • Hi Wayne,

      I am not sure what your decorative panel is, but it sounds like you are removing and replacing it, so it has to be somewhat waterproof. To get the best results from Green Glue, it has to be between 2 rigid surfaces. I suggest that once the decorative panel is off, install the MLV directly to the studs. Then the OSB (3/4″ is better if possible). Then Green Glue and you panels–assuming they are rigid.

      Another option, if you are concerned about waterproofing is MLV to studs, 3/8″ OSB, Green Glue, another layer of 3/8 OSB to make the Green Glue sandwich, then tar paper or house wrap, and finally your decorative panels. I would do it this way because it is only 1/4″ thicker than your original 1/2″ OSB and gives you best soundproofing and waterproofing.

      Hope that makes sense,

      Terry

      Reply

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